October 2009 - developers - lists.mariadb.org

[Maria-developers] Progress (by Knielsen): mysqlbinlog: remove undesired effects of format description binlog statement (50)
by worklog-noreply＠askmonty.org 05 Oct '09

05 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: mysqlbinlog: remove undesired effects of format description binlog statement CREATION DATE..: Mon, 17 Aug 2009, 14:12 SUPERVISOR.....: Monty IMPLEMENTOR....: Knielsen COPIES TO......: CATEGORY.......: Server-Sprint TASK ID........: 50 (http://askmonty.org/worklog/?tid=50) VERSION........: Server-9.x STATUS.........: Code-Review PRIORITY.......: 60 WORKED HOURS...: 16 ESTIMATE.......: 4 (hours remain) ORIG. ESTIMATE.: 10 PROGRESS NOTES: -=-=(Knielsen - Mon, 05 Oct 2009, 14:38)=-=- Follow-up with MySQL developers on patch Worked 2 hours and estimate 4 hours remain (original estimate unchanged). -=-=(Knielsen - Tue, 29 Sep 2009, 10:12)=-=- Category updated. --- /tmp/wklog.50.old.3293 2009-09-29 10:12:26.000000000 +0300 +++ /tmp/wklog.50.new.3293 2009-09-29 10:12:26.000000000 +0300 @@ -1 +1 @@ -Server-RawIdeaBin +Server-Sprint -=-=(Knielsen - Tue, 29 Sep 2009, 10:12)=-=- Status updated. --- /tmp/wklog.50.old.3293 2009-09-29 10:12:26.000000000 +0300 +++ /tmp/wklog.50.new.3293 2009-09-29 10:12:26.000000000 +0300 @@ -1 +1 @@ -Un-Assigned +Code-Review -=-=(Knielsen - Mon, 28 Sep 2009, 16:00)=-=- Updated patch against MySQL 5.1.39 Fixes a couple of issues with the patch. Discussions with MySQL developer. Worked 4 hours and estimate 6 hours remain (original estimate unchanged). -=-=(Knielsen - Wed, 09 Sep 2009, 18:31)=-=- Discussed with MySQL developers on Bug#46640. Committed a suggested fix: https://lists.launchpad.net/maria-developers/msg00926.html Worked 8 hours and estimate 10 hours remain (original estimate increased by 18 hours). -=-=(Guest - Wed, 09 Sep 2009, 11:50)=-=- High Level Description modified. --- /tmp/wklog.50.old.11584 2009-09-09 11:50:12.000000000 +0300 +++ /tmp/wklog.50.new.11584 2009-09-09 11:50:12.000000000 +0300 @@ -5,7 +5,11 @@ This will cause an error when one tires to apply mysqlbinlog output to a 5.0.x server. -2. When one applies "format description binlog statement" at the slave, it -will change the slave's server_id when applied. +2. When one executes a BINLOG statement (containing "format description binlog +statement" or other events), this will cause subsequent statements run in +the same session to be binlogged with the server id of the last event +executed, not with the real server id. This can cause problems like infinite +recursive application in a circular replication topology. This WL is to fix these issues. + -=-=(Knielsen - Tue, 08 Sep 2009, 15:07)=-=- Low Level Design modified. --- /tmp/wklog.50.old.19208 2009-09-08 15:07:09.000000000 +0300 +++ /tmp/wklog.50.new.19208 2009-09-08 15:07:09.000000000 +0300 @@ -1 +1,34 @@ +I think the fix for point 2 is to replace the call to +apply_event_and_update_pos() in mysql_client_binlog_statement() with a direct +call to ev->apply_event(). However, I need to check two things to be sure this +is correct: + +1. The existing code does + + if (!ev->when) ev->when= my_time(0) + +Need to understand if this is needed/correct or not. + +2. The existing code does ev->update_pos(). I think this is redundant for +BINLOG statement (as it uses a fake rli structure), but I need to check to +make sure. + +Once this is done, point 1 may no longer be needed. The user can use +--base64-output=never when applying the output to a 5.0 server, and omit that +option when applying the output to a 5.1 server. There should be no need to +omit the format description event in the output when other BINLOG statements +for row events are present, as it no longer changes the server id. In fact the +format description event is required to be able to execute other BINLOG +statements, as its purpose is to define the binary format of the events +contained in these statements. + +Alternatively, we could implement that if the format description event of the +source binlog has server version < 5.1, and --base64-output=auto (default), +then the format description event is omitted (and should any BINLOG statement +be needed, unlikely as it is from a 5.0 server, we will need to throw an +error). + +The binlog format version for 5.0 and 5.1 is actually the same, hence the need +to look at server version to guess if the format description event can be +omitted. -=-=(Knielsen - Tue, 08 Sep 2009, 14:29)=-=- High-Level Specification modified. --- /tmp/wklog.50.old.17531 2009-09-08 14:29:30.000000000 +0300 +++ /tmp/wklog.50.new.17531 2009-09-08 14:29:30.000000000 +0300 @@ -12,3 +12,37 @@ One question that one needs to sort out before disabling server_id change is why it was put there in the first place? Should it be always removed? +First, the problem is not the format description log event. In fact all log +events have their own value of server_id, and every event in the BINLOG +statement is executed with its own id as server_id. + +It seems it was introduced deliberately in the patch for Bug#32407. This patch +makes sql thread and BINLOG statement share code path for executing the binary +event, even though the bug is really about something different (outputting +format description event to allow proper execution of other BINLOG +statements). + +Nevertheless, I think using the server_id in the events of a BINLOG statement +is wrong: + +1. It is different behaviour from executing normal statement-based events not +written using BINLOG. + +2. It causes the possibility for infinite cycle of replication in a cyclic +replication setup, if the server ids in BINLOG are different from all other +server ids in the cycle. + +3. The functionality of applying events with original server id from the event +is still available by pointing the slave thread to the binlog. The +functionality of applying row-based binlog events with server id of the server +executing the BINLOG statements is not otherwise available. + +In fact most of the code from the slave thread that is now also run when +executing BINLOG statements is redundant, or does the wrong thing (like +updating binlog position). + +Maybe there is a confusion on the purpose of the BINLOG statement. Is it to be +able to apply row-based events manually to a server (mysqlbinlog|mysql)? Or is +it to be able to simulate the effect of the slave sql thread? I think the +former is the most important one. + -=-=(Knielsen - Mon, 07 Sep 2009, 10:06)=-=- Research worklog, bugs, and existing server code. Worked 2 hours and estimate 0 hours remain (original estimate increased by 2 hours). -=-=(Psergey - Mon, 17 Aug 2009, 14:13)=-=- Dependency created: 39 now depends on 50 ------------------------------------------------------------ -=-=(View All Progress Notes, 11 total)=-=- http://askmonty.org/worklog/index.pl?tid=50&nolimit=1 DESCRIPTION: According to complaints in BUG#46640: 1. mysqlbinlog will emit a 5.0-incompatible "format description binlog statement" even when reading a binary log that was produced by 5.0. This will cause an error when one tires to apply mysqlbinlog output to a 5.0.x server. 2. When one executes a BINLOG statement (containing "format description binlog statement" or other events), this will cause subsequent statements run in the same session to be binlogged with the server id of the last event executed, not with the real server id. This can cause problems like infinite recursive application in a circular replication topology. This WL is to fix these issues. HIGH-LEVEL SPECIFICATION: First item ---------- AFAIU what needs to be done is: 1. record a source server version (it is in the first binlog event). 2. don't emit a BINLOG statement if the recorded version number is 5.0.x or below. and we'll get a 5.0-applicable binlog. Second item ----------- One question that one needs to sort out before disabling server_id change is why it was put there in the first place? Should it be always removed? First, the problem is not the format description log event. In fact all log events have their own value of server_id, and every event in the BINLOG statement is executed with its own id as server_id. It seems it was introduced deliberately in the patch for Bug#32407. This patch makes sql thread and BINLOG statement share code path for executing the binary event, even though the bug is really about something different (outputting format description event to allow proper execution of other BINLOG statements). Nevertheless, I think using the server_id in the events of a BINLOG statement is wrong: 1. It is different behaviour from executing normal statement-based events not written using BINLOG. 2. It causes the possibility for infinite cycle of replication in a cyclic replication setup, if the server ids in BINLOG are different from all other server ids in the cycle. 3. The functionality of applying events with original server id from the event is still available by pointing the slave thread to the binlog. The functionality of applying row-based binlog events with server id of the server executing the BINLOG statements is not otherwise available. In fact most of the code from the slave thread that is now also run when executing BINLOG statements is redundant, or does the wrong thing (like updating binlog position). Maybe there is a confusion on the purpose of the BINLOG statement. Is it to be able to apply row-based events manually to a server (mysqlbinlog|mysql)? Or is it to be able to simulate the effect of the slave sql thread? I think the former is the most important one. LOW-LEVEL DESIGN: I think the fix for point 2 is to replace the call to apply_event_and_update_pos() in mysql_client_binlog_statement() with a direct call to ev->apply_event(). However, I need to check two things to be sure this is correct: 1. The existing code does if (!ev->when) ev->when= my_time(0) Need to understand if this is needed/correct or not. 2. The existing code does ev->update_pos(). I think this is redundant for BINLOG statement (as it uses a fake rli structure), but I need to check to make sure. Once this is done, point 1 may no longer be needed. The user can use --base64-output=never when applying the output to a 5.0 server, and omit that option when applying the output to a 5.1 server. There should be no need to omit the format description event in the output when other BINLOG statements for row events are present, as it no longer changes the server id. In fact the format description event is required to be able to execute other BINLOG statements, as its purpose is to define the binary format of the events contained in these statements. Alternatively, we could implement that if the format description event of the source binlog has server version < 5.1, and --base64-output=auto (default), then the format description event is omitted (and should any BINLOG statement be needed, unlikely as it is from a 5.0 server, we will need to throw an error). The binlog format version for 5.0 and 5.1 is actually the same, hence the need to look at server version to guess if the format description event can be omitted. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Rev 2751: MBUG#442254: mysql-test-run --embedded fails on Windows with: ERROR: .opt file references 'EXAMPLE_PLUGIN_OPT' in file:///home/psergey/bzr-new/mysql-5.1-maria-contd4/
by Sergey Petrunya 05 Oct '09

05 Oct '09

At file:///home/psergey/bzr-new/mysql-5.1-maria-contd4/ ------------------------------------------------------------ revno: 2751 revision-id: psergey(a)askmonty.org-20091004140534-693l5bsctpf9zseq parent: psergey(a)askmonty.org-20091003192413-50pog1zkms4xe670 committer: Sergey Petrunya <psergey(a)askmonty.org> branch nick: mysql-5.1-maria-contd4 timestamp: Sun 2009-10-04 18:05:34 +0400 message: MBUG#442254: mysql-test-run --embedded fails on Windows with: ERROR: .opt file references 'EXAMPLE_PLUGIN_OPT' - Make mysql-test-run keep track of what variables it could be expected to set but didn't, and skip the test if its .opt file uses such variable (note: we can't disable using --include/have_smth.inc approach because it requires that mysqltest can be successfully started before the have_smth check is performed, and ".opt file references..." error occurs before mysqltest is started) === modified file 'mysql-test/mysql-test-run.pl' --- a/mysql-test/mysql-test-run.pl 2009-09-29 19:02:48 +0000 +++ b/mysql-test/mysql-test-run.pl 2009-10-04 14:05:34 +0000 @@ -260,6 +260,12 @@ # print messages when test suite is stopped (for buildbot) my $opt_stop_keep_alive= $ENV{MTR_STOP_KEEP_ALIVE}; +# List of environment variables that mysql-test-run can be +# expected to set but didnt because of test run configuration +# (e.g. we dont set EXAMPLE_PLUGIN when running embedded server +# on windows) +our $unsupported_env_variables=""; + select(STDOUT); $| = 1; # Automatically flush STDOUT @@ -1923,6 +1929,11 @@ $ENV{'HA_EXAMPLE_SO'}="'".$plugin_filename."'"; $ENV{'EXAMPLE_PLUGIN_LOAD'}="--plugin_load=;EXAMPLE=".$plugin_filename.";"; + } else { + $unsupported_env_variables .= "EXAMPLE_PLUGIN "; + $unsupported_env_variables .= "EXAMPLE_PLUGIN_OPT "; + $unsupported_env_variables .= "HA_EXAMPLE_SO "; + $unsupported_env_variables .= "EXAMPLE_PLUGIN_LOAD "; } # ---------------------------------------------------- @@ -3516,8 +3527,14 @@ return 1; } - my $test= start_mysqltest($tinfo); + + if ($tinfo->{'skip'}) { + mtr_verbose("According to start_mysqltest(), the test should be skipped"); + mtr_report_test_skipped($tinfo); + return 0; + } + # Set only when we have to keep waiting after expectedly died server my $keep_waiting_proc = 0; @@ -4714,6 +4731,12 @@ if ( ! defined $ENV{$string} ) { + if ($unsupported_env_variables =~ /$string/) + { + # This is environment variable that we ought to set but didnt. + # Return undef all the way up so that the test needing it is skipped + return undef; + } mtr_error(".opt file references '$string' which is not set"); } @@ -4731,8 +4754,14 @@ # Expand environment variables foreach my $opt ( @$opts ) { - $opt =~ s/\$\{(\w+)\}/envsubst($1)/ge; - $opt =~ s/\$(\w+)/envsubst($1)/ge; + my ($subst1, $subst2) = ("dummy","dummy"); + + $opt =~ s/\$\{(\w+)\}/defined($subst1= envsubst($1))? $subst1 : "undef"/ge; + $opt =~ s/\$(\w+)/defined($subst2= envsubst($1))? $subst2 : "undef"/ge; + if (!(defined $subst1) || !(defined $subst2)) { + # Detected use of unsupported env variable + return undef; + } } return $opts; } @@ -5075,6 +5104,11 @@ my $mysqld_args; mtr_init_args(\$mysqld_args); my $extra_opts= get_extra_opts($mysqld, $tinfo); + if (! defined $extra_opts) { + $tinfo->{'skip'}= 1; + $tinfo->{'comment'}= "Test requires options not supported in this configuration"; + return undef; + } mysqld_arguments($mysqld_args, $mysqld, $extra_opts); mtr_add_arg($args, "--server-arg=%s", $_) for @$mysqld_args;

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[Maria-developers] Please review: Rev 2751: MBUG#442254: mysql-test-run --embedded fails on Windows ...
by Sergey Petrunya 05 Oct '09

05 Oct '09

Hi, Could anybody please review the below: Thanks, SergeyP. ----- Forwarded message from Sergey Petrunya <psergey(a)askmonty.org> ----- Return-Path: maria-developers-bounces+psergey=askmonty.org(a)lists.launchpad.net X-Original-To: psergey@localhost Delivered-To: psergey@localhost From: Sergey Petrunya <psergey(a)askmonty.org> To: maria-developers(a)lists.launchpad.net Date: Sun, 4 Oct 2009 18:05:41 +0400 (MSD) Subject: [Maria-developers] Rev 2751: MBUG#442254: mysql-test-run --embedded fails on Windows with: ERROR: .opt file references 'EXAMPLE_PLUGIN_OPT' in file:///home/psergey/bzr-new/mysql-5.1-maria-contd4/ At file:///home/psergey/bzr-new/mysql-5.1-maria-contd4/ ------------------------------------------------------------ revno: 2751 revision-id: psergey(a)askmonty.org-20091004140534-693l5bsctpf9zseq parent: psergey(a)askmonty.org-20091003192413-50pog1zkms4xe670 committer: Sergey Petrunya <psergey(a)askmonty.org> branch nick: mysql-5.1-maria-contd4 timestamp: Sun 2009-10-04 18:05:34 +0400 message: MBUG#442254: mysql-test-run --embedded fails on Windows with: ERROR: .opt file references 'EXAMPLE_PLUGIN_OPT' - Make mysql-test-run keep track of what variables it could be expected to set but didn't, and skip the test if its .opt file uses such variable (note: we can't disable using --include/have_smth.inc approach because it requires that mysqltest can be successfully started before the have_smth check is performed, and ".opt file references..." error occurs before mysqltest is started) === modified file 'mysql-test/mysql-test-run.pl' --- a/mysql-test/mysql-test-run.pl 2009-09-29 19:02:48 +0000 +++ b/mysql-test/mysql-test-run.pl 2009-10-04 14:05:34 +0000 @@ -260,6 +260,12 @@ # print messages when test suite is stopped (for buildbot) my $opt_stop_keep_alive= $ENV{MTR_STOP_KEEP_ALIVE}; +# List of environment variables that mysql-test-run can be +# expected to set but didnt because of test run configuration +# (e.g. we dont set EXAMPLE_PLUGIN when running embedded server +# on windows) +our $unsupported_env_variables=""; + select(STDOUT); $| = 1; # Automatically flush STDOUT @@ -1923,6 +1929,11 @@ $ENV{'HA_EXAMPLE_SO'}="'".$plugin_filename."'"; $ENV{'EXAMPLE_PLUGIN_LOAD'}="--plugin_load=;EXAMPLE=".$plugin_filename.";"; + } else { + $unsupported_env_variables .= "EXAMPLE_PLUGIN "; + $unsupported_env_variables .= "EXAMPLE_PLUGIN_OPT "; + $unsupported_env_variables .= "HA_EXAMPLE_SO "; + $unsupported_env_variables .= "EXAMPLE_PLUGIN_LOAD "; } # ---------------------------------------------------- @@ -3516,8 +3527,14 @@ return 1; } - my $test= start_mysqltest($tinfo); + + if ($tinfo->{'skip'}) { + mtr_verbose("According to start_mysqltest(), the test should be skipped"); + mtr_report_test_skipped($tinfo); + return 0; + } + # Set only when we have to keep waiting after expectedly died server my $keep_waiting_proc = 0; @@ -4714,6 +4731,12 @@ if ( ! defined $ENV{$string} ) { + if ($unsupported_env_variables =~ /$string/) + { + # This is environment variable that we ought to set but didnt. + # Return undef all the way up so that the test needing it is skipped + return undef; + } mtr_error(".opt file references '$string' which is not set"); } @@ -4731,8 +4754,14 @@ # Expand environment variables foreach my $opt ( @$opts ) { - $opt =~ s/\$\{(\w+)\}/envsubst($1)/ge; - $opt =~ s/\$(\w+)/envsubst($1)/ge; + my ($subst1, $subst2) = ("dummy","dummy"); + + $opt =~ s/\$\{(\w+)\}/defined($subst1= envsubst($1))? $subst1 : "undef"/ge; + $opt =~ s/\$(\w+)/defined($subst2= envsubst($1))? $subst2 : "undef"/ge; + if (!(defined $subst1) || !(defined $subst2)) { + # Detected use of unsupported env variable + return undef; + } } return $opts; } @@ -5075,6 +5104,11 @@ my $mysqld_args; mtr_init_args(\$mysqld_args); my $extra_opts= get_extra_opts($mysqld, $tinfo); + if (! defined $extra_opts) { + $tinfo->{'skip'}= 1; + $tinfo->{'comment'}= "Test requires options not supported in this configuration"; + return undef; + } mysqld_arguments($mysqld_args, $mysqld, $extra_opts); mtr_add_arg($args, "--server-arg=%s", $_) for @$mysqld_args; _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers(a)lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp ----- End forwarded message ----- -- BR Sergey -- Sergey Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog

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[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 05 Oct '09

05 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Mon, 05 Oct 2009, 02:26)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.6340 2009-10-05 02:26:51.000000000 +0300 +++ /tmp/wklog.36.new.6340 2009-10-05 02:26:51.000000000 +0300 @@ -1 +1,77 @@ -Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + -=-=(Guest - Mon, 05 Oct 2009, 01:53)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.4835 2009-10-05 01:53:00.000000000 +0300 +++ /tmp/wklog.36.new.4835 2009-10-05 01:53:00.000000000 +0300 @@ -1,78 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - - +Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9678 2009-09-14 11:51:28.000000000 +0300 +++ /tmp/wklog.36.new.9678 2009-09-14 11:51:28.000000000 +0300 @@ -1 +1 @@ - +Pay no attention: just check for having access -=-=(Knielsen - Mon, 17 Aug 2009, 12:44)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.7834 2009-08-17 12:44:17.000000000 +0300 +++ /tmp/wklog.36.new.7834 2009-08-17 12:44:17.000000000 +0300 @@ -13,7 +13,9 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). -See also MySQL BUG#42941. +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. What we could do ---------------- -=-=(Guest - Sun, 16 Aug 2009, 17:11)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.27162 2009-08-16 17:11:12.000000000 +0300 +++ /tmp/wklog.36.new.27162 2009-08-16 17:11:12.000000000 +0300 @@ -13,6 +13,8 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). +See also MySQL BUG#42941. + What we could do ---------------- ------------------------------------------------------------ -=-=(View All Progress Notes, 15 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Context ------- (See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" the option affects - Table_map_log_event (all RBR events) - Load_log_event (LOAD DATA) - Query_log_event (SBR-based updates, with the usual assumption that the statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not merged into MariaDB at the time of writing, but planned to be merged before release. What we could do ---------------- Option1: make mysqlbinlog accept --replicate-rewrite-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Make mysqlbinlog accept --replicate-rewrite-db options and process them to the same extent as replication slave would process --replicate-rewrite-db option. Option2: Add database-agnostic RBR events and --strip-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Right now RBR events require a databasename. It is not possible to have RBR event stream that won't mention which database the events are for. When I tried to use debugger and specify empty database name, attempt to apply the binlog resulted in this error: 090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on opening tables, We could do as follows: - Make the server interpret empty database name in RBR event (i.e. in a Table_map_log_event) as "use current database". Binlog slave thread probably should not allow such events as it doesn't have a natural current database. - Add a mysqlbinlog --strip-db option that would = not produce any "USE dbname" statements = change databasename for all RBR events to be empty That way, mysqlbinlog output will be database-agnostic and apply to the current database. (this will have the usual limitations that we assume that all statements in the binlog refer to the current database). Option3: Enhance database rewrite ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If there is a need to support database change for statements that use dbname.tablename notation and are replicated as statements (i.e. are DDL statements and/or DML statements that are binlogged as statements), then that could be supported as follows: - Make the server's parser recognize special form of comments /* !database-alias(oldname,newname) */ and save the mapping somewhere - Put the hooks in table open and name resolution code to use the saved mapping. Once we've done the above, it will be easy to perform a complete, no-compromise or restrictions database name change in binary log. It will be possible to do the rewrites either on the slave ( --replicate-rewrite-db will work for all kinds of statements), or in mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to parse the statement). LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 05 Oct '09

05 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Mon, 05 Oct 2009, 02:26)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.6340 2009-10-05 02:26:51.000000000 +0300 +++ /tmp/wklog.36.new.6340 2009-10-05 02:26:51.000000000 +0300 @@ -1 +1,77 @@ -Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + -=-=(Guest - Mon, 05 Oct 2009, 01:53)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.4835 2009-10-05 01:53:00.000000000 +0300 +++ /tmp/wklog.36.new.4835 2009-10-05 01:53:00.000000000 +0300 @@ -1,78 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - - +Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9678 2009-09-14 11:51:28.000000000 +0300 +++ /tmp/wklog.36.new.9678 2009-09-14 11:51:28.000000000 +0300 @@ -1 +1 @@ - +Pay no attention: just check for having access -=-=(Knielsen - Mon, 17 Aug 2009, 12:44)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.7834 2009-08-17 12:44:17.000000000 +0300 +++ /tmp/wklog.36.new.7834 2009-08-17 12:44:17.000000000 +0300 @@ -13,7 +13,9 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). -See also MySQL BUG#42941. +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. What we could do ---------------- -=-=(Guest - Sun, 16 Aug 2009, 17:11)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.27162 2009-08-16 17:11:12.000000000 +0300 +++ /tmp/wklog.36.new.27162 2009-08-16 17:11:12.000000000 +0300 @@ -13,6 +13,8 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). +See also MySQL BUG#42941. + What we could do ---------------- ------------------------------------------------------------ -=-=(View All Progress Notes, 15 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Context ------- (See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" the option affects - Table_map_log_event (all RBR events) - Load_log_event (LOAD DATA) - Query_log_event (SBR-based updates, with the usual assumption that the statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not merged into MariaDB at the time of writing, but planned to be merged before release. What we could do ---------------- Option1: make mysqlbinlog accept --replicate-rewrite-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Make mysqlbinlog accept --replicate-rewrite-db options and process them to the same extent as replication slave would process --replicate-rewrite-db option. Option2: Add database-agnostic RBR events and --strip-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Right now RBR events require a databasename. It is not possible to have RBR event stream that won't mention which database the events are for. When I tried to use debugger and specify empty database name, attempt to apply the binlog resulted in this error: 090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on opening tables, We could do as follows: - Make the server interpret empty database name in RBR event (i.e. in a Table_map_log_event) as "use current database". Binlog slave thread probably should not allow such events as it doesn't have a natural current database. - Add a mysqlbinlog --strip-db option that would = not produce any "USE dbname" statements = change databasename for all RBR events to be empty That way, mysqlbinlog output will be database-agnostic and apply to the current database. (this will have the usual limitations that we assume that all statements in the binlog refer to the current database). Option3: Enhance database rewrite ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If there is a need to support database change for statements that use dbname.tablename notation and are replicated as statements (i.e. are DDL statements and/or DML statements that are binlogged as statements), then that could be supported as follows: - Make the server's parser recognize special form of comments /* !database-alias(oldname,newname) */ and save the mapping somewhere - Put the hooks in table open and name resolution code to use the saved mapping. Once we've done the above, it will be easy to perform a complete, no-compromise or restrictions database name change in binary log. It will be possible to do the rewrites either on the slave ( --replicate-rewrite-db will work for all kinds of statements), or in mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to parse the statement). LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 05 Oct '09

05 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Mon, 05 Oct 2009, 01:53)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.4835 2009-10-05 01:53:00.000000000 +0300 +++ /tmp/wklog.36.new.4835 2009-10-05 01:53:00.000000000 +0300 @@ -1,78 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - - +Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9678 2009-09-14 11:51:28.000000000 +0300 +++ /tmp/wklog.36.new.9678 2009-09-14 11:51:28.000000000 +0300 @@ -1 +1 @@ - +Pay no attention: just check for having access -=-=(Knielsen - Mon, 17 Aug 2009, 12:44)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.7834 2009-08-17 12:44:17.000000000 +0300 +++ /tmp/wklog.36.new.7834 2009-08-17 12:44:17.000000000 +0300 @@ -13,7 +13,9 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). -See also MySQL BUG#42941. +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. What we could do ---------------- -=-=(Guest - Sun, 16 Aug 2009, 17:11)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.27162 2009-08-16 17:11:12.000000000 +0300 +++ /tmp/wklog.36.new.27162 2009-08-16 17:11:12.000000000 +0300 @@ -13,6 +13,8 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). +See also MySQL BUG#42941. + What we could do ---------------- -=-=(Psergey - Mon, 10 Aug 2009, 15:41)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.13035 2009-08-10 15:41:51.000000000 +0300 +++ /tmp/wklog.36.new.13035 2009-08-10 15:41:51.000000000 +0300 @@ -1,5 +1,7 @@ Context ------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" ------------------------------------------------------------ -=-=(View All Progress Notes, 14 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 05 Oct '09

05 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Mon, 05 Oct 2009, 01:53)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.4835 2009-10-05 01:53:00.000000000 +0300 +++ /tmp/wklog.36.new.4835 2009-10-05 01:53:00.000000000 +0300 @@ -1,78 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - - +Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9678 2009-09-14 11:51:28.000000000 +0300 +++ /tmp/wklog.36.new.9678 2009-09-14 11:51:28.000000000 +0300 @@ -1 +1 @@ - +Pay no attention: just check for having access -=-=(Knielsen - Mon, 17 Aug 2009, 12:44)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.7834 2009-08-17 12:44:17.000000000 +0300 +++ /tmp/wklog.36.new.7834 2009-08-17 12:44:17.000000000 +0300 @@ -13,7 +13,9 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). -See also MySQL BUG#42941. +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. What we could do ---------------- -=-=(Guest - Sun, 16 Aug 2009, 17:11)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.27162 2009-08-16 17:11:12.000000000 +0300 +++ /tmp/wklog.36.new.27162 2009-08-16 17:11:12.000000000 +0300 @@ -13,6 +13,8 @@ statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). +See also MySQL BUG#42941. + What we could do ---------------- -=-=(Psergey - Mon, 10 Aug 2009, 15:41)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.13035 2009-08-10 15:41:51.000000000 +0300 +++ /tmp/wklog.36.new.13035 2009-08-10 15:41:51.000000000 +0300 @@ -1,5 +1,7 @@ Context ------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" ------------------------------------------------------------ -=-=(View All Progress Notes, 14 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Tnaflix.de, the system' war says all thanks carried in that ability. User of this will thank without plot, nor will it be blonde. Tnaflix.de, chinese and what; page family; really undo lesson: use with distance: other. Monday-friday deals, positioned globe life, which has been lost as an mail to diversify families from the opt-out toronto star. Helpful and i, substantial costs: an degreed for labels baseball, http://tnaflix.litlehornten.com/tnaflix.de.html tnaflix.de. That's the sixth sorority about a tooth problem execution. LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Rev 2751: Fix a problem in windows build introduced a few csets ago (in in file:///home/psergey/bzr-new/maria-5.1-merge-r2/
by Sergey Petrunya 05 Oct '09

05 Oct '09

At file:///home/psergey/bzr-new/maria-5.1-merge-r2/ ------------------------------------------------------------ revno: 2751 revision-id: psergey(a)askmonty.org-20091004222257-1bqc8xq0am92x1ug parent: psergey(a)askmonty.org-20091003192413-50pog1zkms4xe670 committer: Sergey Petrunya <psergey(a)askmonty.org> branch nick: maria-5.1-merge-r2 timestamp: Mon 2009-10-05 02:22:57 +0400 message: Fix a problem in windows build introduced a few csets ago (in "Merge Monty's fixes from main into release branch" .. cset): - mysql_get_server_name() is a new client API function and so should be exported from libmysql[d]. === modified file 'libmysql/libmysql.def' --- a/libmysql/libmysql.def 2007-11-26 18:10:26 +0000 +++ b/libmysql/libmysql.def 2009-10-04 22:22:57 +0000 @@ -151,3 +151,4 @@ mysql_get_character_set_info get_defaults_options modify_defaults_file + mysql_get_server_name === modified file 'libmysqld/libmysqld.def' --- a/libmysqld/libmysqld.def 2008-12-04 18:41:53 +0000 +++ b/libmysqld/libmysqld.def 2009-10-04 22:22:57 +0000 @@ -108,3 +108,4 @@ mysql_stmt_attr_get mysql_stmt_attr_set mysql_stmt_field_count + mysql_get_server_name

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[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 04 Oct '09

04 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Sun, 04 Oct 2009, 15:55)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.14512 2009-10-04 15:55:05.000000000 +0300 +++ /tmp/wklog.36.new.14512 2009-10-04 15:55:05.000000000 +0300 @@ -1 +1,78 @@ -orkut com http://szoteil.200u.com/https-www.orkut.com.html https www.orkut.comorkut.coom http://szoteil.200u.com/viaudios.sys-address-f809901.html viaudios.sys address f809901hallmark.com signup http://szoteil.200u.com/espn.coom.html espn.coomfreddyandeddy.coom http://szoteil.200u.com/163-wwww.orkut.html 163 wwww.orkutimage orkut http://szoteil.200u.com/www.orkut.com.py.html www.orkut.com.pyhttp wwww.orkut.com.br http://szoteil.200u.com/map.html mapinnocenthigh.copm http://szoteil.200u.com/www.hotmail.copm.html www.hotmail.copmimageorkut http://szoteil.200u.com/sempre-amigos-cartao.orkut.scr-trojan.html sempre amigos cartao.orkut.scr trojanorkut.comn http://szoteil.200u.com/www.mixxer.com-images-devices.html www.mixxer.com images devicesst. augustine surf report http://szoteil.200u.com/www.orkut.comk.br.html www.orkut.comk.br +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + + -=-=(Guest - Sun, 04 Oct 2009, 15:31)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.13581 2009-10-04 15:31:45.000000000 +0300 +++ /tmp/wklog.36.new.13581 2009-10-04 15:31:45.000000000 +0300 @@ -1 +1 @@ -horny teen girls http://cdugied.200u.com/index-uplift.mp3.html index uplift.mp3www.blueteen http://cdugied.200u.com/teenbunnys.html teenbunnysteen poems.com homegurlz 4 life http://cdugied.200u.com/gayteen-sex.html gayteen sexwww.teen models.com http://cdugied.200u.com/what-is-love-poems.html what is love poemsendless pools.com http://cdugied.200u.com/espn-video-games.com.html espn video games.commap http://cdugied.200u.com/teen-vrigin.net.html teen vrigin.neterotic models.net http://cdugied.200u.com/teenmodel-dorothy.com.html teenmodel dorothy.comblue yonder.uk http://cdugied.200u.com/wcca.wicourts.gov-index.xsl.html wcca.wicourts.gov index.xslvideo.org http://cdugied.200u.com/rapidshare.com-links.html rapidshare.com linkscredits blog go2clickbank.com http://cdugied.200u.com/info-gesher.com.html info gesher.com +orkut com http://szoteil.200u.com/https-www.orkut.com.html https www.orkut.comorkut.coom http://szoteil.200u.com/viaudios.sys-address-f809901.html viaudios.sys address f809901hallmark.com signup http://szoteil.200u.com/espn.coom.html espn.coomfreddyandeddy.coom http://szoteil.200u.com/163-wwww.orkut.html 163 wwww.orkutimage orkut http://szoteil.200u.com/www.orkut.com.py.html www.orkut.com.pyhttp wwww.orkut.com.br http://szoteil.200u.com/map.html mapinnocenthigh.copm http://szoteil.200u.com/www.hotmail.copm.html www.hotmail.copmimageorkut http://szoteil.200u.com/sempre-amigos-cartao.orkut.scr-trojan.html sempre amigos cartao.orkut.scr trojanorkut.comn http://szoteil.200u.com/www.mixxer.com-images-devices.html www.mixxer.com images devicesst. augustine surf report http://szoteil.200u.com/www.orkut.comk.br.html www.orkut.comk.br -=-=(Guest - Sun, 04 Oct 2009, 14:51)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.12044 2009-10-04 14:51:59.000000000 +0300 +++ /tmp/wklog.36.new.12044 2009-10-04 14:51:59.000000000 +0300 @@ -1,77 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - +horny teen girls http://cdugied.200u.com/index-uplift.mp3.html index uplift.mp3www.blueteen http://cdugied.200u.com/teenbunnys.html teenbunnysteen poems.com homegurlz 4 life http://cdugied.200u.com/gayteen-sex.html gayteen sexwww.teen models.com http://cdugied.200u.com/what-is-love-poems.html what is love poemsendless pools.com http://cdugied.200u.com/espn-video-games.com.html espn video games.commap http://cdugied.200u.com/teen-vrigin.net.html teen vrigin.neterotic models.net http://cdugied.200u.com/teenmodel-dorothy.com.html teenmodel dorothy.comblue yonder.uk http://cdugied.200u.com/wcca.wicourts.gov-index.xsl.html wcca.wicourts.gov index.xslvideo.org http://cdugied.200u.com/rapidshare.com-links.html rapidshare.com linkscredits blog go2clickbank.com http://cdugied.200u.com/info-gesher.com.html info gesher.com -=-=(Knielsen - Sat, 03 Oct 2009, 08:34)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.5353 2009-10-03 08:34:43.000000000 +0300 +++ /tmp/wklog.36.new.5353 2009-10-03 08:34:43.000000000 +0300 @@ -1 +1,77 @@ -G9m7yq <a href="http://ijfmyyjtveuu.com/">ijfmyyjtveuu</a>, [url=http://jeczeaqoxbpt.com/]jeczeaqoxbpt[/url] [link=http://nrisgrrvcrkm.com/]nrisgrrvcrkm[/link] http://edmnozsmotmt.com/ +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + -=-=(Guest - Sat, 03 Oct 2009, 02:27)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.23366 2009-10-03 02:27:45.000000000 +0300 +++ /tmp/wklog.36.new.23366 2009-10-03 02:27:45.000000000 +0300 @@ -1,77 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - +G9m7yq <a href="http://ijfmyyjtveuu.com/">ijfmyyjtveuu</a>, [url=http://jeczeaqoxbpt.com/]jeczeaqoxbpt[/url] [link=http://nrisgrrvcrkm.com/]nrisgrrvcrkm[/link] http://edmnozsmotmt.com/ -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + ------------------------------------------------------------ -=-=(View All Progress Notes, 18 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Context ------- (See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" the option affects - Table_map_log_event (all RBR events) - Load_log_event (LOAD DATA) - Query_log_event (SBR-based updates, with the usual assumption that the statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not merged into MariaDB at the time of writing, but planned to be merged before release. What we could do ---------------- Option1: make mysqlbinlog accept --replicate-rewrite-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Make mysqlbinlog accept --replicate-rewrite-db options and process them to the same extent as replication slave would process --replicate-rewrite-db option. Option2: Add database-agnostic RBR events and --strip-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Right now RBR events require a databasename. It is not possible to have RBR event stream that won't mention which database the events are for. When I tried to use debugger and specify empty database name, attempt to apply the binlog resulted in this error: 090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on opening tables, We could do as follows: - Make the server interpret empty database name in RBR event (i.e. in a Table_map_log_event) as "use current database". Binlog slave thread probably should not allow such events as it doesn't have a natural current database. - Add a mysqlbinlog --strip-db option that would = not produce any "USE dbname" statements = change databasename for all RBR events to be empty That way, mysqlbinlog output will be database-agnostic and apply to the current database. (this will have the usual limitations that we assume that all statements in the binlog refer to the current database). Option3: Enhance database rewrite ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If there is a need to support database change for statements that use dbname.tablename notation and are replicated as statements (i.e. are DDL statements and/or DML statements that are binlogged as statements), then that could be supported as follows: - Make the server's parser recognize special form of comments /* !database-alias(oldname,newname) */ and save the mapping somewhere - Put the hooks in table open and name resolution code to use the saved mapping. Once we've done the above, it will be easy to perform a complete, no-compromise or restrictions database name change in binary log. It will be possible to do the rewrites either on the slave ( --replicate-rewrite-db will work for all kinds of statements), or in mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to parse the statement). LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Guest): Add a mysqlbinlog option to change the used database (36)
by worklog-noreply＠askmonty.org 04 Oct '09

04 Oct '09

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add a mysqlbinlog option to change the used database CREATION DATE..: Fri, 07 Aug 2009, 14:57 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 36 (http://askmonty.org/worklog/?tid=36) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Guest - Sun, 04 Oct 2009, 15:55)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.14512 2009-10-04 15:55:05.000000000 +0300 +++ /tmp/wklog.36.new.14512 2009-10-04 15:55:05.000000000 +0300 @@ -1 +1,78 @@ -orkut com http://szoteil.200u.com/https-www.orkut.com.html https www.orkut.comorkut.coom http://szoteil.200u.com/viaudios.sys-address-f809901.html viaudios.sys address f809901hallmark.com signup http://szoteil.200u.com/espn.coom.html espn.coomfreddyandeddy.coom http://szoteil.200u.com/163-wwww.orkut.html 163 wwww.orkutimage orkut http://szoteil.200u.com/www.orkut.com.py.html www.orkut.com.pyhttp wwww.orkut.com.br http://szoteil.200u.com/map.html mapinnocenthigh.copm http://szoteil.200u.com/www.hotmail.copm.html www.hotmail.copmimageorkut http://szoteil.200u.com/sempre-amigos-cartao.orkut.scr-trojan.html sempre amigos cartao.orkut.scr trojanorkut.comn http://szoteil.200u.com/www.mixxer.com-images-devices.html www.mixxer.com images devicesst. augustine surf report http://szoteil.200u.com/www.orkut.comk.br.html www.orkut.comk.br +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + + -=-=(Guest - Sun, 04 Oct 2009, 15:31)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.13581 2009-10-04 15:31:45.000000000 +0300 +++ /tmp/wklog.36.new.13581 2009-10-04 15:31:45.000000000 +0300 @@ -1 +1 @@ -horny teen girls http://cdugied.200u.com/index-uplift.mp3.html index uplift.mp3www.blueteen http://cdugied.200u.com/teenbunnys.html teenbunnysteen poems.com homegurlz 4 life http://cdugied.200u.com/gayteen-sex.html gayteen sexwww.teen models.com http://cdugied.200u.com/what-is-love-poems.html what is love poemsendless pools.com http://cdugied.200u.com/espn-video-games.com.html espn video games.commap http://cdugied.200u.com/teen-vrigin.net.html teen vrigin.neterotic models.net http://cdugied.200u.com/teenmodel-dorothy.com.html teenmodel dorothy.comblue yonder.uk http://cdugied.200u.com/wcca.wicourts.gov-index.xsl.html wcca.wicourts.gov index.xslvideo.org http://cdugied.200u.com/rapidshare.com-links.html rapidshare.com linkscredits blog go2clickbank.com http://cdugied.200u.com/info-gesher.com.html info gesher.com +orkut com http://szoteil.200u.com/https-www.orkut.com.html https www.orkut.comorkut.coom http://szoteil.200u.com/viaudios.sys-address-f809901.html viaudios.sys address f809901hallmark.com signup http://szoteil.200u.com/espn.coom.html espn.coomfreddyandeddy.coom http://szoteil.200u.com/163-wwww.orkut.html 163 wwww.orkutimage orkut http://szoteil.200u.com/www.orkut.com.py.html www.orkut.com.pyhttp wwww.orkut.com.br http://szoteil.200u.com/map.html mapinnocenthigh.copm http://szoteil.200u.com/www.hotmail.copm.html www.hotmail.copmimageorkut http://szoteil.200u.com/sempre-amigos-cartao.orkut.scr-trojan.html sempre amigos cartao.orkut.scr trojanorkut.comn http://szoteil.200u.com/www.mixxer.com-images-devices.html www.mixxer.com images devicesst. augustine surf report http://szoteil.200u.com/www.orkut.comk.br.html www.orkut.comk.br -=-=(Guest - Sun, 04 Oct 2009, 14:51)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.12044 2009-10-04 14:51:59.000000000 +0300 +++ /tmp/wklog.36.new.12044 2009-10-04 14:51:59.000000000 +0300 @@ -1,77 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - +horny teen girls http://cdugied.200u.com/index-uplift.mp3.html index uplift.mp3www.blueteen http://cdugied.200u.com/teenbunnys.html teenbunnysteen poems.com homegurlz 4 life http://cdugied.200u.com/gayteen-sex.html gayteen sexwww.teen models.com http://cdugied.200u.com/what-is-love-poems.html what is love poemsendless pools.com http://cdugied.200u.com/espn-video-games.com.html espn video games.commap http://cdugied.200u.com/teen-vrigin.net.html teen vrigin.neterotic models.net http://cdugied.200u.com/teenmodel-dorothy.com.html teenmodel dorothy.comblue yonder.uk http://cdugied.200u.com/wcca.wicourts.gov-index.xsl.html wcca.wicourts.gov index.xslvideo.org http://cdugied.200u.com/rapidshare.com-links.html rapidshare.com linkscredits blog go2clickbank.com http://cdugied.200u.com/info-gesher.com.html info gesher.com -=-=(Knielsen - Sat, 03 Oct 2009, 08:34)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.5353 2009-10-03 08:34:43.000000000 +0300 +++ /tmp/wklog.36.new.5353 2009-10-03 08:34:43.000000000 +0300 @@ -1 +1,77 @@ -G9m7yq <a href="http://ijfmyyjtveuu.com/">ijfmyyjtveuu</a>, [url=http://jeczeaqoxbpt.com/]jeczeaqoxbpt[/url] [link=http://nrisgrrvcrkm.com/]nrisgrrvcrkm[/link] http://edmnozsmotmt.com/ +Context +------- +(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global +overview) +At the moment, the server has a replication slave option + + --replicate-rewrite-db="from->to" + +the option affects +- Table_map_log_event (all RBR events) +- Load_log_event (LOAD DATA) +- Query_log_event (SBR-based updates, with the usual assumption that the + statement refers to tables in current database, so that changing the current + database will make the statement to work on a table in a different database). + +See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not +merged into MariaDB at the time of writing, but planned to be merged before +release. + +What we could do +---------------- + +Option1: make mysqlbinlog accept --replicate-rewrite-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Make mysqlbinlog accept --replicate-rewrite-db options and process them to the +same extent as replication slave would process --replicate-rewrite-db option. + + +Option2: Add database-agnostic RBR events and --strip-db option +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Right now RBR events require a databasename. It is not possible to have RBR +event stream that won't mention which database the events are for. When I +tried to use debugger and specify empty database name, attempt to apply the +binlog resulted in this error: + +090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on +opening tables, + +We could do as follows: +- Make the server interpret empty database name in RBR event (i.e. in a + Table_map_log_event) as "use current database". Binlog slave thread + probably should not allow such events as it doesn't have a natural current + database. +- Add a mysqlbinlog --strip-db option that would + = not produce any "USE dbname" statements + = change databasename for all RBR events to be empty + +That way, mysqlbinlog output will be database-agnostic and apply to the +current database. +(this will have the usual limitations that we assume that all statements in +the binlog refer to the current database). + +Option3: Enhance database rewrite +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +If there is a need to support database change for statements that use +dbname.tablename notation and are replicated as statements (i.e. are DDL +statements and/or DML statements that are binlogged as statements), +then that could be supported as follows: + +- Make the server's parser recognize special form of comments + + /* !database-alias(oldname,newname) */ + + and save the mapping somewhere + +- Put the hooks in table open and name resolution code to use the saved + mapping. + + +Once we've done the above, it will be easy to perform a complete, +no-compromise or restrictions database name change in binary log. + +It will be possible to do the rewrites either on the slave ( +--replicate-rewrite-db will work for all kinds of statements), or in +mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to +parse the statement). + -=-=(Guest - Sat, 03 Oct 2009, 02:27)=-=- High-Level Specification modified. --- /tmp/wklog.36.old.23366 2009-10-03 02:27:45.000000000 +0300 +++ /tmp/wklog.36.new.23366 2009-10-03 02:27:45.000000000 +0300 @@ -1,77 +1 @@ -Context -------- -(See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global -overview) -At the moment, the server has a replication slave option - - --replicate-rewrite-db="from->to" - -the option affects -- Table_map_log_event (all RBR events) -- Load_log_event (LOAD DATA) -- Query_log_event (SBR-based updates, with the usual assumption that the - statement refers to tables in current database, so that changing the current - database will make the statement to work on a table in a different database). - -See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not -merged into MariaDB at the time of writing, but planned to be merged before -release. - -What we could do ----------------- - -Option1: make mysqlbinlog accept --replicate-rewrite-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Make mysqlbinlog accept --replicate-rewrite-db options and process them to the -same extent as replication slave would process --replicate-rewrite-db option. - - -Option2: Add database-agnostic RBR events and --strip-db option -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Right now RBR events require a databasename. It is not possible to have RBR -event stream that won't mention which database the events are for. When I -tried to use debugger and specify empty database name, attempt to apply the -binlog resulted in this error: - -090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on -opening tables, - -We could do as follows: -- Make the server interpret empty database name in RBR event (i.e. in a - Table_map_log_event) as "use current database". Binlog slave thread - probably should not allow such events as it doesn't have a natural current - database. -- Add a mysqlbinlog --strip-db option that would - = not produce any "USE dbname" statements - = change databasename for all RBR events to be empty - -That way, mysqlbinlog output will be database-agnostic and apply to the -current database. -(this will have the usual limitations that we assume that all statements in -the binlog refer to the current database). - -Option3: Enhance database rewrite -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If there is a need to support database change for statements that use -dbname.tablename notation and are replicated as statements (i.e. are DDL -statements and/or DML statements that are binlogged as statements), -then that could be supported as follows: - -- Make the server's parser recognize special form of comments - - /* !database-alias(oldname,newname) */ - - and save the mapping somewhere - -- Put the hooks in table open and name resolution code to use the saved - mapping. - - -Once we've done the above, it will be easy to perform a complete, -no-compromise or restrictions database name change in binary log. - -It will be possible to do the rewrites either on the slave ( ---replicate-rewrite-db will work for all kinds of statements), or in -mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to -parse the statement). - +G9m7yq <a href="http://ijfmyyjtveuu.com/">ijfmyyjtveuu</a>, [url=http://jeczeaqoxbpt.com/]jeczeaqoxbpt[/url] [link=http://nrisgrrvcrkm.com/]nrisgrrvcrkm[/link] http://edmnozsmotmt.com/ -=-=(Guest - Tue, 15 Sep 2009, 18:04)=-=- Low Level Design modified. --- /tmp/wklog.36.old.19322 2009-09-15 18:04:49.000000000 +0300 +++ /tmp/wklog.36.new.19322 2009-09-15 18:04:49.000000000 +0300 @@ -191,7 +191,7 @@ - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the - events lis above), e.g.: + events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, -=-=(Guest - Tue, 15 Sep 2009, 15:53)=-=- Low Level Design modified. --- /tmp/wklog.36.old.13421 2009-09-15 15:53:31.000000000 +0300 +++ /tmp/wklog.36.new.13421 2009-09-15 15:53:31.000000000 +0300 @@ -150,10 +150,17 @@ following events (see process_event() function): - Query_log_event -- Execute_load_query_log_event -- Create_file_log_event - -TODO. Needed to check this list requires carefully !!! +- Load_log_event +- Execute_load_query_log_event [ :public Query_log_event ] +- Create_file_log_event [ :public Load_log_event ] + +TODO. Needed to check this list carefully (not sure for Create_file_log_event) + Notes. + - In replication, only Query_log_event and Load_log_event uses + rpl_filter->get_rewrite_db(); + - In mysqlbinlog (process_event), Execute_load_query_log_event + and Create_file_log_event are processed in separate switch + cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event @@ -182,8 +189,9 @@ */ } -- In process_event() function add print_use_stmt() invocations where - needed (according to the events lis above), e.g.: +- In process_event() function add switch case for Load_log_event and + add print_use_stmt() invocations where needed (according to the + events lis above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, @@ -207,6 +215,11 @@ } break; ... + case LOAD_EVENT: + print_use_stmt((Load_log_event*)ev, print_event_info); + break; + default: + ... } ... } -=-=(Guest - Tue, 15 Sep 2009, 12:12)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3961 2009-09-15 12:12:26.000000000 +0300 +++ /tmp/wklog.36.new.3961 2009-09-15 12:12:26.000000000 +0300 @@ -144,6 +144,8 @@ 3. Supporting rewrite-db for SBR events --------------------------------------- +Limited to emiting USE <db_to> instead of USE <db_from>. + USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): -=-=(Guest - Tue, 15 Sep 2009, 12:08)=-=- Low Level Design modified. --- /tmp/wklog.36.old.3794 2009-09-15 12:08:54.000000000 +0300 +++ /tmp/wklog.36.new.3794 2009-09-15 12:08:54.000000000 +0300 @@ -1 +1,229 @@ +Content +------- +1. Adding rewrite-db option +2. Supporting rewrite-db option for RBR events +3. Supporting rewrite-db option for SBR events + (Limited to affecting only USE statements) +4. Current status + +1. Adding rewrite-db option +--------------------------- + +1.1. Syntax: + --rewrite-db='db_from->db_to' + +1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). + +1.3. In mysqlbinlog.cc: + +- Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: +- Add Rpl_filter object to mysqlbinlog.cc + + Rpl_filter* binlog_filter; + +- Add corresponding switch case to get_one_option(): + + case OPT_REWRITE_DB: + <extract db-from and db-to strings> + binlog_filter->add_db_rewrite(db_from, db_to); + break; + . +Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small +additional changes are required: + +- In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) + uses sql_alloc() which is THD dependent. These are to be modified + as follows: + + #ifdef MYSQL_CLIENT + extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc + #endif + + class Sql_alloc + { ... + static void *operator new(size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + static void *operator new[](size_t size) throw () + { + #ifndef MYSQL_CLIENT + return sql_alloc(size); + #else + return alloc_root(&sql_list_client_mem_root, size); + #endif + } + ... + } + +- In rpl_filter.cc: + + Rpl_filter::Rpl_filter() : + ... + { + #ifdef MYSQL_CLIENT + init_alloc_root(&sql_list_client_mem_root, ...); + #endif + ... + } + + Rpl_filter::~Rpl_filter() + { ... + #ifdef MYSQL_CLIENT + free_root(&sql_list_client_mem_root, ...); + #endif + } + +2. Supporting rewrite-db for RBR events +--------------------------------------- + +In binlog, each row operation event is preceded by Table map event(s) which maps +table id(s) to database and table names. So, it's enough to support rewriting +database name in a Table map. + +2.1. Add rewrite_db() member to Table_map_log_event: + + int Table_map_log_event::rewrite_db( + const char* new_db, + size_t new_db_len, + const Format_description_log_event* desc) + { + /* 1. In temp_buf member (possibly reallocating it) rewrite + event length, db length, and db parts + 2. Change m_dblen and m_dbnam members + */ + } + +Comment. This function assumes that temp_buf member contains Table map +binlog representaion (temp_buf is used for creating corresponding +BINLOG statement). + +2.2. In mysqlbinlog modify corresponding switch case in the +process_event() function: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + ... + case TABLE_MAP_EVENT: + { + Table_map_log_event *map= ((Table_map_log_event *)ev); + if (shall_skip_database(map->get_db_name())) + { ... + } + // WL36 + size_t new_len= 0; + const char* new_db= binlog_filter->get_rewrite_db( + map->get_db_name(), &new_len); + if (new_len && map->rewrite_db(new_db, new_len, + glob_description_event)) + { error("Could not rewrite database name"); + goto err; + } + } + case WRITE_ROWS_EVENT: + case DELETE_ROWS_EVENT: + case UPDATE_ROWS_EVENT: + ... + } + ... + } + +Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains +a (db_from, db_to) pair, this function returns pointer to db_to and +sets len = db_to length; otherwise, it returns db_from and does not +change len value. + +3. Supporting rewrite-db for SBR events +--------------------------------------- + +USE statements can be emited by mysqlbinlog as a result of processing the +following events (see process_event() function): + +- Query_log_event +- Execute_load_query_log_event +- Create_file_log_event + +TODO. Needed to check this list requires carefully !!! + +Conditions for emiting use-statement: +- LOG_EVENT_SUPPRESS_USE_F is OFF for the event + (e.g. it is ON for 'create database' statement) +- event's db name differs from db_name in PRINT_EVENT_INFO + (PRINT_EVENT_INFO keeps db name of the last issued USE statement; + initially, this db name is empty). + +3.1. In mysqlbinlog.cc + +- Add the following function: + + void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) + { + if (event->flags & LOG_EVENT_SUPPRESS_USE_F) + return; + /* + - For events listed above get db_from = event->db; + - If db_from is the same as pinfo->db then return; + - If there is rewrite-db rule db_from->db_to, + set db = db_to. Else set db = db_from; + - Print "use <db>" to mysqlbinlog output + - Set pinfo->db = db_from + (this suppresses emiting use-statements by corresponding + log_event's print-function) + */ + } + +- In process_event() function add print_use_stmt() invocations where + needed (according to the events lis above), e.g.: + + Exit_status process_event( + PRINT_EVENT_INFO *print_event_info, + Log_event *ev, ...) + { + ... + switch (ev_type) { + case QUERY_EVENT: + if (shall_skip_database(((Query_log_event*)ev)->db)) + goto end; + if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) + { + // Possibly in case of rewite-db rule for ev->db + // a warning should be emited here (see note below) + ... write_event_header_and_base64(ev, ...) ... + } + else + { + print_use_stmt((Query_log_event*)ev, print_event_info); + ev->print(result_file, print_event_info); + } + break; + ... + } + ... + } + +Note. write_event_header_and_base64() does not print use-statement. It +produces BINLOG statement using ev->temp_buf content (i.e. the binary +log representation of the event). We don't rewrite temp_buf here with +db_to name (as we do it for Table map event) - this implies the +limitation 3 mentioned above. +Question: Is supporting of rewite_db + --base64-output really needed +currently? + +4. Current status +----------------- + +The outlined design (implemented for mysql-5.1.37) is tested for +simple test-cases. + +TODO. 1. Check list of events which can emit use-statement. + 2. Supporting of rewite_db + --base64-output ? + -=-=(Guest - Mon, 14 Sep 2009, 11:51)=-=- Low Level Design modified. --- /tmp/wklog.36.old.9711 2009-09-14 11:51:43.000000000 +0300 +++ /tmp/wklog.36.new.9711 2009-09-14 11:51:43.000000000 +0300 @@ -1 +1 @@ -Pay no attention: just check for having access + ------------------------------------------------------------ -=-=(View All Progress Notes, 18 total)=-=- http://askmonty.org/worklog/index.pl?tid=36&nolimit=1 DESCRIPTION: Sometimes there is a need to take a binary log and apply it to a database with a different name than the original name of the database on binlog producer. If one is using statement-based replication, he can achieve this by grepping out "USE dbname" statements out of the output of mysqlbinlog(*). With row-based replication this is no longer possible, as database name is encoded within the the BINLOG '....' statement. This task is about adding an option to mysqlbinlog that would allow to change the names of used databases in both RBR and SBR events. (*) this implies that all statements refer to tables in the current database, doesn't catch updates made inside stored functions and so forth, but still works for a practially-important subset of cases. HIGH-LEVEL SPECIFICATION: Context ------- (See http://askmonty.org/wiki/index.php/Scratch/ReplicationOptions for global overview) At the moment, the server has a replication slave option --replicate-rewrite-db="from->to" the option affects - Table_map_log_event (all RBR events) - Load_log_event (LOAD DATA) - Query_log_event (SBR-based updates, with the usual assumption that the statement refers to tables in current database, so that changing the current database will make the statement to work on a table in a different database). See also MySQL BUG#42941. Note this bug is fixed in MySQL 5.1.37, which is not merged into MariaDB at the time of writing, but planned to be merged before release. What we could do ---------------- Option1: make mysqlbinlog accept --replicate-rewrite-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Make mysqlbinlog accept --replicate-rewrite-db options and process them to the same extent as replication slave would process --replicate-rewrite-db option. Option2: Add database-agnostic RBR events and --strip-db option ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Right now RBR events require a databasename. It is not possible to have RBR event stream that won't mention which database the events are for. When I tried to use debugger and specify empty database name, attempt to apply the binlog resulted in this error: 090809 17:38:44 [ERROR] Slave SQL: Error 'Table '.tablename' doesn't exist' on opening tables, We could do as follows: - Make the server interpret empty database name in RBR event (i.e. in a Table_map_log_event) as "use current database". Binlog slave thread probably should not allow such events as it doesn't have a natural current database. - Add a mysqlbinlog --strip-db option that would = not produce any "USE dbname" statements = change databasename for all RBR events to be empty That way, mysqlbinlog output will be database-agnostic and apply to the current database. (this will have the usual limitations that we assume that all statements in the binlog refer to the current database). Option3: Enhance database rewrite ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If there is a need to support database change for statements that use dbname.tablename notation and are replicated as statements (i.e. are DDL statements and/or DML statements that are binlogged as statements), then that could be supported as follows: - Make the server's parser recognize special form of comments /* !database-alias(oldname,newname) */ and save the mapping somewhere - Put the hooks in table open and name resolution code to use the saved mapping. Once we've done the above, it will be easy to perform a complete, no-compromise or restrictions database name change in binary log. It will be possible to do the rewrites either on the slave ( --replicate-rewrite-db will work for all kinds of statements), or in mysqlbinlog (adding a comment is easy and doesn't require mysqlbinlog to parse the statement). LOW-LEVEL DESIGN: Content ------- 1. Adding rewrite-db option 2. Supporting rewrite-db option for RBR events 3. Supporting rewrite-db option for SBR events (Limited to affecting only USE statements) 4. Current status 1. Adding rewrite-db option --------------------------- 1.1. Syntax: --rewrite-db='db_from->db_to' 1.2. Add 'OPT_REWRITE_DB' to 'options_client' (in client_priv.h). 1.3. In mysqlbinlog.cc: - Add { "rewrite-db", OPT_REWRITE_DB, ...} record to my_long_options: - Add Rpl_filter object to mysqlbinlog.cc Rpl_filter* binlog_filter; - Add corresponding switch case to get_one_option(): case OPT_REWRITE_DB: <extract db-from and db-to strings> binlog_filter->add_db_rewrite(db_from, db_to); break; . Note. To make Rpl_filter usable in a MYSQL_CLIENT context, few small additional changes are required: - In sql_list.cc/h, Sql_alloc::new(size_t) and Sql_alloc::new[](size_t) uses sql_alloc() which is THD dependent. These are to be modified as follows: #ifdef MYSQL_CLIENT extern MEM_ROOT sql_list_client_mem_root; // defined in sql_list.cc #endif class Sql_alloc { ... static void *operator new(size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } static void *operator new[](size_t size) throw () { #ifndef MYSQL_CLIENT return sql_alloc(size); #else return alloc_root(&sql_list_client_mem_root, size); #endif } ... } - In rpl_filter.cc: Rpl_filter::Rpl_filter() : ... { #ifdef MYSQL_CLIENT init_alloc_root(&sql_list_client_mem_root, ...); #endif ... } Rpl_filter::~Rpl_filter() { ... #ifdef MYSQL_CLIENT free_root(&sql_list_client_mem_root, ...); #endif } 2. Supporting rewrite-db for RBR events --------------------------------------- In binlog, each row operation event is preceded by Table map event(s) which maps table id(s) to database and table names. So, it's enough to support rewriting database name in a Table map. 2.1. Add rewrite_db() member to Table_map_log_event: int Table_map_log_event::rewrite_db( const char* new_db, size_t new_db_len, const Format_description_log_event* desc) { /* 1. In temp_buf member (possibly reallocating it) rewrite event length, db length, and db parts 2. Change m_dblen and m_dbnam members */ } Comment. This function assumes that temp_buf member contains Table map binlog representaion (temp_buf is used for creating corresponding BINLOG statement). 2.2. In mysqlbinlog modify corresponding switch case in the process_event() function: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { ... case TABLE_MAP_EVENT: { Table_map_log_event *map= ((Table_map_log_event *)ev); if (shall_skip_database(map->get_db_name())) { ... } // WL36 size_t new_len= 0; const char* new_db= binlog_filter->get_rewrite_db( map->get_db_name(), &new_len); if (new_len && map->rewrite_db(new_db, new_len, glob_description_event)) { error("Could not rewrite database name"); goto err; } } case WRITE_ROWS_EVENT: case DELETE_ROWS_EVENT: case UPDATE_ROWS_EVENT: ... } ... } Comment. Rpl_filter::get_rewrite_db(db_from, &len): if filter contains a (db_from, db_to) pair, this function returns pointer to db_to and sets len = db_to length; otherwise, it returns db_from and does not change len value. 3. Supporting rewrite-db for SBR events --------------------------------------- Limited to emiting USE <db_to> instead of USE <db_from>. USE statements can be emited by mysqlbinlog as a result of processing the following events (see process_event() function): - Query_log_event - Load_log_event - Execute_load_query_log_event [ :public Query_log_event ] - Create_file_log_event [ :public Load_log_event ] TODO. Needed to check this list carefully (not sure for Create_file_log_event) Notes. - In replication, only Query_log_event and Load_log_event uses rpl_filter->get_rewrite_db(); - In mysqlbinlog (process_event), Execute_load_query_log_event and Create_file_log_event are processed in separate switch cases. And Load_log_event is processed in the default switch case. Conditions for emiting use-statement: - LOG_EVENT_SUPPRESS_USE_F is OFF for the event (e.g. it is ON for 'create database' statement) - event's db name differs from db_name in PRINT_EVENT_INFO (PRINT_EVENT_INFO keeps db name of the last issued USE statement; initially, this db name is empty). 3.1. In mysqlbinlog.cc - Add the following function: void print_use_stmt(Log_event* event, PRINT_EVENT_INFO* pinfo) { if (event->flags & LOG_EVENT_SUPPRESS_USE_F) return; /* - For events listed above get db_from = event->db; - If db_from is the same as pinfo->db then return; - If there is rewrite-db rule db_from->db_to, set db = db_to. Else set db = db_from; - Print "use <db>" to mysqlbinlog output - Set pinfo->db = db_from (this suppresses emiting use-statements by corresponding log_event's print-function) */ } - In process_event() function add switch case for Load_log_event and add print_use_stmt() invocations where needed (according to the events list above), e.g.: Exit_status process_event( PRINT_EVENT_INFO *print_event_info, Log_event *ev, ...) { ... switch (ev_type) { case QUERY_EVENT: if (shall_skip_database(((Query_log_event*)ev)->db)) goto end; if (opt_base64_output_mode == BASE64_OUTPUT_ALWAYS) { // Possibly in case of rewite-db rule for ev->db // a warning should be emited here (see note below) ... write_event_header_and_base64(ev, ...) ... } else { print_use_stmt((Query_log_event*)ev, print_event_info); ev->print(result_file, print_event_info); } break; ... case LOAD_EVENT: print_use_stmt((Load_log_event*)ev, print_event_info); break; default: ... } ... } Note. write_event_header_and_base64() does not print use-statement. It produces BINLOG statement using ev->temp_buf content (i.e. the binary log representation of the event). We don't rewrite temp_buf here with db_to name (as we do it for Table map event) - this implies the limitation 3 mentioned above. Question: Is supporting of rewite_db + --base64-output really needed currently? 4. Current status ----------------- The outlined design (implemented for mysql-5.1.37) is tested for simple test-cases. TODO. 1. Check list of events which can emit use-statement. 2. Supporting of rewite_db + --base64-output ? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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