February 2010 - developers - lists.mariadb.org

[Maria-developers] Ideas for improving MariaDB/MySQL replication
by Kristian Nielsen 06 Jul '10

06 Jul '10

The three companies Continuent, Codership, and Monty Program are planning to start working on some enhancements to the replication system in MariaDB, together with anyone interested in joining in. At this stage, there are no fixed directions for the project, and to do this in as open a way possible with the maximum community involvement and interest, we agreed to start with an email discussion on the maria-developers@ mailing list. So consider it started! The plan so far is: 1) The parties taking this initiative, MP, Continuent, and Codership, present their own ideas in this thread on maria-developers@ (and everyone else who wants to chime in at this stage). 2) Once we have some concrete suggestions as a starting point, we use this to reach out in a broader way with some blog posts on planetmysql / planetmariadb to encourage further input and discussions for possible directions of the project. Eventually we want to end up with a list of the most important goals and a possible roadmap for replication enhancements. (It is best to have something concrete as a basis of a broad community discussion/process). To start of, here are some points of interest that I collected. Everyone please chime in with your own additional points, as well as comments and further details on these one. Three areas in particular seem to be of high interest in the community currently (not excluding any other areas): - High Availability * Most seems to focus on building HA solutions on top of MySQL replication, eg. MMM and Tungsten. * For this project, seems mainly to be to implement improvements to replication that help facilitate improving these on-top HA solutions. * Tools to automate (or help automate) failover from a master. * Better facilities to do initial setup of new slave without downtime, or re-sync of an old master or slave that has been outside of the replication topology for some period of time. - Performance, especially scalability * Multi-threaded slave SQL thread. * Store the binlog inside a transactional engine (eg. InnoDB) to reduce I/O, solve problems like group commit, and simplify crash recovery. - More pluggable replication * Make the replication code and APIs be more suitable for people to build extra functionality into or on top of the stock MySQL replication. * Better documentation of C++ APIs and binlog format. * Adding extra information to binlog that can be useful for non-standard replication stuff. For example column names (for RBR), checksums. * Refactoring the server code to be more modular with APIs more suitable for external usage. * Add support for replication plugins, types to be determined. For example binlog filtering plugins? It is also very important to consider the work that the replication team at MySQL is doing (and has done). I found a good deal of interesting information about this here: http://forge.mysql.com/wiki/MySQL_Replication:_Walk-through_of_the_new_5.1_…) This describes a number of 6.0/5.4 and preview features that we could merge and/or contribute to. Here are the highlights that I found: - Features included in 6.0/5.4 (which are cancelled I think, but presumably this will go in a milestone release): * CHANGE MASTER ... IGNORE_SERVER_IDS for better support of circular replication. * Replication heartbeat. * sync_relay_log_info, sync_master_info, sync_relay_log, relay_log_recovery for crash recovery on slave. * Binlog Performance Optimization (lock contention improvement). * Semi-synchronous Replication, with Pluggable Replication Architecture. http://forge.mysql.com/wiki/ReplicationFeatures/SemiSyncReplication - Feature previews: * Parallel slave application: WL#4648 http://forge.mysql.com/wiki/ReplicationFeatures/ParallelSlave * Time-delayed replication: WL#344 http://forge.mysql.com/wiki/ReplicationFeatures/DelayedReplication * Scriptable Replication: WL#4008 http://forge.mysql.com/wiki/ReplicationFeatures/ScriptableReplication * Synchronous Replication. Drizzle is also doing work on a new replication system. I read through the series of blog posts that Jay Pipes wrote on this subject. They mostly deal with how this is designed in terms of the Drizzle server code, and is low on detail about how the replication will actually work (the only thing I could really extract was that it is a form of row-based replication). If someone has links to information about this that I missed, it could be interesting. Let the discussion begin! - Kristian.

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[Maria-developers] LIMIT optimisations
by Jocelyn Fournier 11 Mar '10

11 Mar '10

Hi, Following this discussion in 2007 : http://lists.mysql.com/internals/34287 Is there any plan to implement such an optimisation in MariaDB ? (I think a lot of web app using pagination could take benefit of such an optimisation, although there are some workarounds to avoid big LIMIT for pagination) Thanks ! Jocelyn

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[Maria-developers] Rev 2818: Increased loop counts of sql-bench tests to get run times around in file:///Users/hakan/work/monty_program/maria/
by Hakan Kuecuekyilmaz 10 Mar '10

10 Mar '10

At file:///Users/hakan/work/monty_program/maria/ ------------------------------------------------------------ revno: 2818 revision-id: hakan(a)askmonty.org-20100217201002-gax8y3ts7yf6u50a parent: monty(a)askmonty.org-20100212142113-wdv50xx19quursaf committer: Hakan Kuecuekyilmaz <hakan(a)askmonty.org> branch nick: maria timestamp: Wed 2010-02-17 21:10:02 +0100 message: Increased loop counts of sql-bench tests to get run times around 5 minutes on current machines. Tested on a Xeon machine and a new dual core laptop. === modified file 'sql-bench/test-ATIS.sh' --- a/sql-bench/test-ATIS.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-ATIS.sh 2010-02-17 20:10:02 +0000 @@ -28,7 +28,7 @@ use DBI; use Benchmark; -$opt_loop_count=100; # Run selects this many times +$opt_loop_count=5000; # Run selects this many times $pwd = cwd(); $pwd = "." if ($pwd eq ''); require "$pwd/bench-init.pl" || die "Can't read Configuration file: $!\n"; === modified file 'sql-bench/test-alter-table.sh' --- a/sql-bench/test-alter-table.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-alter-table.sh 2010-02-17 20:10:02 +0000 @@ -25,7 +25,7 @@ use Benchmark; $opt_start_field_count=8; # start with this many fields -$opt_loop_count=100; # How many tests to do +$opt_loop_count=10000; # How many tests to do $opt_row_count=1000; # Rows in the table $opt_field_count=1000; # Add until this many fields. $opt_time_limit=10*60; # Don't wait more than 10 min for some tests === modified file 'sql-bench/test-big-tables.sh' --- a/sql-bench/test-big-tables.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-big-tables.sh 2010-02-17 20:10:02 +0000 @@ -25,7 +25,7 @@ use DBI; use Benchmark; -$opt_loop_count=1000; # Change this to make test harder/easier +$opt_loop_count=70000; # Change this to make test harder/easier $opt_field_count=1000; $pwd = cwd(); $pwd = "." if ($pwd eq ''); === modified file 'sql-bench/test-connect.sh' --- a/sql-bench/test-connect.sh 2010-02-10 21:26:06 +0000 +++ b/sql-bench/test-connect.sh 2010-02-17 20:10:02 +0000 @@ -28,7 +28,7 @@ use DBI; use Benchmark; -$opt_loop_count=100000; # Change this to make test harder/easier +$opt_loop_count=500000; # Change this to make test harder/easier $str_length=65000; # This is the length of blob strings in PART:5 $max_test=20; # How many times to test if the server is busy === modified file 'sql-bench/test-select.sh' --- a/sql-bench/test-select.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-select.sh 2010-02-17 20:10:02 +0000 @@ -26,7 +26,7 @@ use Benchmark; $opt_loop_count=10000; -$opt_medium_loop_count=1000; +$opt_medium_loop_count=7000; $opt_small_loop_count=10; $opt_regions=6; $opt_groups=100; === modified file 'sql-bench/test-transactions.sh' --- a/sql-bench/test-transactions.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-transactions.sh 2010-02-17 20:10:02 +0000 @@ -28,8 +28,8 @@ $opt_groups=27; # Characters are 'A' -> Z -$opt_loop_count=10000; # Change this to make test harder/easier -$opt_medium_loop_count=100; # Change this to make test harder/easier +$opt_loop_count=500000; # Change this to make test harder/easier +$opt_medium_loop_count=10000; # Change this to make test harder/easier $pwd = cwd(); $pwd = "." if ($pwd eq ''); require "$pwd/bench-init.pl" || die "Can't read Configuration file: $!\n"; === modified file 'sql-bench/test-wisconsin.sh' --- a/sql-bench/test-wisconsin.sh 2009-05-29 13:40:55 +0000 +++ b/sql-bench/test-wisconsin.sh 2010-02-17 20:10:02 +0000 @@ -21,7 +21,7 @@ use DBI; use Benchmark; -$opt_loop_count=10; +$opt_loop_count=5000; $pwd = cwd(); $pwd = "." if ($pwd eq ''); require "$pwd/bench-init.pl" || die "Can't read Configuration file: $!\n";

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[Maria-developers] Fwd: DELAY_KEY_WRITE und MariaDB
by Hakan Kuecuekyilmaz 10 Mar '10

10 Mar '10

Hi, Oli Sennhauser is asking how DELAY_KEY_WRITE is working in MariDB? Is it different or better performing than the MySQL one? Best regards, Hakan Begin forwarded message: > From: "oli.sennhauser(a)bluewin.ch" <oli.sennhauser(a)bluewin.ch> > Date: 16. Februar 2010 11:41:26 MEZ > To: hakan(a)askmonty.org > Subject: DELAY_KEY_WRITE und MariaDB > Reply-To: oli.sennhauser(a)bluewin.ch > > Hoi Hakan, > > Hast Du infos wie sich DELAY_KEY_WRITE auf MariaDB auswirkt? Alles gleich oder viel bessert/schlechter? Performance? > > Danke und Gruss, > Oli -- Hakan Küçükyılmaz, QA/Benchmark Engineer, Stuttgart/Germany Monty Program Ab, http://askmonty.org/ Skype: hakank_ Phone: +49 171 1919839

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[Maria-developers] LOCK_plugin in pbxt_init()
by Sergei Golubchik 04 Mar '10

04 Mar '10

Hi, Paul, I was backporting libservices to MariaDB, and with a related test case found a bug in MariaDB - mutexes were locked in the wrong order. I've fixed that some time ago in mysql-next, so I took the fix from there - the fix was to not lock LOCK_plugin over the plugin initialization code. After that pbxt started crashing here: #if MYSQL_VERSION_ID < 60014 myxt_mutex_unlock(&LOCK_plugin); #endif as it was unlocking the mutex that was not locked. For now I simply commented out your locking/unlocking of this mutex in the MariaDB tree. But probably you may want a better fix, may be even your FREERER-HANG problem will go away too ? I've submitted http://bugs.mysql.com/51591 hopefully it will be fixed in MySQL too. Regards, Sergei

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[Maria-developers] request for advice on managing a mysql patch in bzr
by MARK CALLAGHAN 01 Mar '10

01 Mar '10

I know this question is more about official MySQL than MariaDB, but it is also about sharing code we write at Facebook and all of the patches we publish can be reused by others as long as others accept BSD contributions. I am getting ready to publish facebook patches for mysql 5.1. We use git internally and are based on MySQL 5.1.44. We intend to stay current with 5.1 releases. What is the best way to manage the code in launchpad across new releases of official MySQL. My current plan is: 1) import MySQL 5.1.44, commit 2) apply patches from my git repo to my bzr repo, commit after each one 3) publish But there will soon be a release of 5.1.45 or 5.1.46 and I don't want to repeat the steps above each time that happens. Do I just publish a large patch for 5.1.44 -> 5.1.4X and get on with my work? Is there a better way? -- Mark Callaghan mdcallag(a)gmail.com

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[Maria-developers] Updated (by Psergey): Subqueries backport: fix known semi-join subquery bugs (92)
by worklog-noreply＠askmonty.org 28 Feb '10

28 Feb '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Subqueries backport: fix known semi-join subquery bugs CREATION DATE..: Sun, 28 Feb 2010, 14:02 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: Igor, Psergey, Timour CATEGORY.......: Server-RawIdeaBin TASK ID........: 92 (http://askmonty.org/worklog/?tid=92) VERSION........: WorkLog-3.4 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 28 Feb 2010, 16:41)=-=- High Level Description modified. --- /tmp/wklog.92.old.24539 2010-02-28 16:41:06.000000000 +0000 +++ /tmp/wklog.92.new.24539 2010-02-28 16:41:06.000000000 +0000 @@ -1 +1,4 @@ We must fix known subquery semi-join bugs. +* outer join + semi join problem +* Duplicate Weedout + join caching problem. + -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- High Level Description modified. --- /tmp/wklog.92.old.22593 2010-02-28 15:06:23.000000000 +0000 +++ /tmp/wklog.92.new.22593 2010-02-28 15:06:23.000000000 +0000 @@ -1 +1 @@ - +We must fix known subquery semi-join bugs. -=-=(Psergey - Sun, 28 Feb 2010, 15:03)=-=- Title modified. --- /tmp/wklog.92.old.22572 2010-02-28 15:03:51.000000000 +0000 +++ /tmp/wklog.92.new.22572 2010-02-28 15:03:51.000000000 +0000 @@ -1 +1 @@ -Unused +Subqueries backport: fix known semi-join subquery bugs -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency deleted: 91 no longer depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- High Level Description modified. --- /tmp/wklog.92.old.22267 2010-02-28 14:57:52.000000000 +0000 +++ /tmp/wklog.92.new.22267 2010-02-28 14:57:52.000000000 +0000 @@ -1 +1 @@ -We must fix known semi-join subquery bugs. + -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- Title modified. --- /tmp/wklog.92.old.22249 2010-02-28 14:57:41.000000000 +0000 +++ /tmp/wklog.92.new.22249 2010-02-28 14:57:41.000000000 +0000 @@ -1 +1 @@ -Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE +Unused -=-=(Psergey - Sun, 28 Feb 2010, 14:51)=-=- High Level Description modified. --- /tmp/wklog.92.old.21961 2010-02-28 14:51:06.000000000 +0000 +++ /tmp/wklog.92.new.21961 2010-02-28 14:51:06.000000000 +0000 @@ -1,18 +1 @@ -Consider the following case: - -SELECT * FROM big_table -WHERE oe IN (SELECT ie FROM table_with_few_groups - WHERE ... - GROUP BY group_col) AND ... - -Here the best way to execute the query is: - - Materialize the subquery; - # now run the join: - for each record R1 in materialized table - for each record R2 in big_table such that oe=R1 - pass R2 to output - -Semi-join materialization supports such strategy with SJM-Scan strategy. This WL -entry is about adding support for such strategies for non-semijoin subqueries. - +We must fix known semi-join subquery bugs. -=-=(Psergey - Sun, 28 Feb 2010, 14:03)=-=- Observers changed: Psergey,Igor,Timour DESCRIPTION: We must fix known subquery semi-join bugs. * outer join + semi join problem * Duplicate Weedout + join caching problem. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Updated (by Psergey): Subqueries backport: fix known semi-join subquery bugs (92)
by worklog-noreply＠askmonty.org 28 Feb '10

28 Feb '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Subqueries backport: fix known semi-join subquery bugs CREATION DATE..: Sun, 28 Feb 2010, 14:02 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: Igor, Psergey, Timour CATEGORY.......: Server-RawIdeaBin TASK ID........: 92 (http://askmonty.org/worklog/?tid=92) VERSION........: WorkLog-3.4 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 28 Feb 2010, 16:41)=-=- High Level Description modified. --- /tmp/wklog.92.old.24539 2010-02-28 16:41:06.000000000 +0000 +++ /tmp/wklog.92.new.24539 2010-02-28 16:41:06.000000000 +0000 @@ -1 +1,4 @@ We must fix known subquery semi-join bugs. +* outer join + semi join problem +* Duplicate Weedout + join caching problem. + -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- High Level Description modified. --- /tmp/wklog.92.old.22593 2010-02-28 15:06:23.000000000 +0000 +++ /tmp/wklog.92.new.22593 2010-02-28 15:06:23.000000000 +0000 @@ -1 +1 @@ - +We must fix known subquery semi-join bugs. -=-=(Psergey - Sun, 28 Feb 2010, 15:03)=-=- Title modified. --- /tmp/wklog.92.old.22572 2010-02-28 15:03:51.000000000 +0000 +++ /tmp/wklog.92.new.22572 2010-02-28 15:03:51.000000000 +0000 @@ -1 +1 @@ -Unused +Subqueries backport: fix known semi-join subquery bugs -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency deleted: 91 no longer depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- High Level Description modified. --- /tmp/wklog.92.old.22267 2010-02-28 14:57:52.000000000 +0000 +++ /tmp/wklog.92.new.22267 2010-02-28 14:57:52.000000000 +0000 @@ -1 +1 @@ -We must fix known semi-join subquery bugs. + -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- Title modified. --- /tmp/wklog.92.old.22249 2010-02-28 14:57:41.000000000 +0000 +++ /tmp/wklog.92.new.22249 2010-02-28 14:57:41.000000000 +0000 @@ -1 +1 @@ -Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE +Unused -=-=(Psergey - Sun, 28 Feb 2010, 14:51)=-=- High Level Description modified. --- /tmp/wklog.92.old.21961 2010-02-28 14:51:06.000000000 +0000 +++ /tmp/wklog.92.new.21961 2010-02-28 14:51:06.000000000 +0000 @@ -1,18 +1 @@ -Consider the following case: - -SELECT * FROM big_table -WHERE oe IN (SELECT ie FROM table_with_few_groups - WHERE ... - GROUP BY group_col) AND ... - -Here the best way to execute the query is: - - Materialize the subquery; - # now run the join: - for each record R1 in materialized table - for each record R2 in big_table such that oe=R1 - pass R2 to output - -Semi-join materialization supports such strategy with SJM-Scan strategy. This WL -entry is about adding support for such strategies for non-semijoin subqueries. - +We must fix known semi-join subquery bugs. -=-=(Psergey - Sun, 28 Feb 2010, 14:03)=-=- Observers changed: Psergey,Igor,Timour DESCRIPTION: We must fix known subquery semi-join bugs. * outer join + semi join problem * Duplicate Weedout + join caching problem. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Updated (by Psergey): Subqueries backport: fix known semi-join subquery bugs (92)
by worklog-noreply＠askmonty.org 28 Feb '10

28 Feb '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Subqueries backport: fix known semi-join subquery bugs CREATION DATE..: Sun, 28 Feb 2010, 14:02 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: Igor, Psergey, Timour CATEGORY.......: Server-RawIdeaBin TASK ID........: 92 (http://askmonty.org/worklog/?tid=92) VERSION........: WorkLog-3.4 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 28 Feb 2010, 16:41)=-=- High Level Description modified. --- /tmp/wklog.92.old.24539 2010-02-28 16:41:06.000000000 +0000 +++ /tmp/wklog.92.new.24539 2010-02-28 16:41:06.000000000 +0000 @@ -1 +1,4 @@ We must fix known subquery semi-join bugs. +* outer join + semi join problem +* Duplicate Weedout + join caching problem. + -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- High Level Description modified. --- /tmp/wklog.92.old.22593 2010-02-28 15:06:23.000000000 +0000 +++ /tmp/wklog.92.new.22593 2010-02-28 15:06:23.000000000 +0000 @@ -1 +1 @@ - +We must fix known subquery semi-join bugs. -=-=(Psergey - Sun, 28 Feb 2010, 15:03)=-=- Title modified. --- /tmp/wklog.92.old.22572 2010-02-28 15:03:51.000000000 +0000 +++ /tmp/wklog.92.new.22572 2010-02-28 15:03:51.000000000 +0000 @@ -1 +1 @@ -Unused +Subqueries backport: fix known semi-join subquery bugs -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency deleted: 91 no longer depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- High Level Description modified. --- /tmp/wklog.92.old.22267 2010-02-28 14:57:52.000000000 +0000 +++ /tmp/wklog.92.new.22267 2010-02-28 14:57:52.000000000 +0000 @@ -1 +1 @@ -We must fix known semi-join subquery bugs. + -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- Title modified. --- /tmp/wklog.92.old.22249 2010-02-28 14:57:41.000000000 +0000 +++ /tmp/wklog.92.new.22249 2010-02-28 14:57:41.000000000 +0000 @@ -1 +1 @@ -Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE +Unused -=-=(Psergey - Sun, 28 Feb 2010, 14:51)=-=- High Level Description modified. --- /tmp/wklog.92.old.21961 2010-02-28 14:51:06.000000000 +0000 +++ /tmp/wklog.92.new.21961 2010-02-28 14:51:06.000000000 +0000 @@ -1,18 +1 @@ -Consider the following case: - -SELECT * FROM big_table -WHERE oe IN (SELECT ie FROM table_with_few_groups - WHERE ... - GROUP BY group_col) AND ... - -Here the best way to execute the query is: - - Materialize the subquery; - # now run the join: - for each record R1 in materialized table - for each record R2 in big_table such that oe=R1 - pass R2 to output - -Semi-join materialization supports such strategy with SJM-Scan strategy. This WL -entry is about adding support for such strategies for non-semijoin subqueries. - +We must fix known semi-join subquery bugs. -=-=(Psergey - Sun, 28 Feb 2010, 14:03)=-=- Observers changed: Psergey,Igor,Timour DESCRIPTION: We must fix known subquery semi-join bugs. * outer join + semi join problem * Duplicate Weedout + join caching problem. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Updated (by Psergey): Subqueries backport: fix known semi-join subquery bugs (92)
by worklog-noreply＠askmonty.org 28 Feb '10

28 Feb '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Subqueries backport: fix known semi-join subquery bugs CREATION DATE..: Sun, 28 Feb 2010, 14:02 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: Igor, Psergey, Timour CATEGORY.......: Server-RawIdeaBin TASK ID........: 92 (http://askmonty.org/worklog/?tid=92) VERSION........: WorkLog-3.4 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 28 Feb 2010, 16:41)=-=- High Level Description modified. --- /tmp/wklog.92.old.24539 2010-02-28 16:41:06.000000000 +0000 +++ /tmp/wklog.92.new.24539 2010-02-28 16:41:06.000000000 +0000 @@ -1 +1,4 @@ We must fix known subquery semi-join bugs. +* outer join + semi join problem +* Duplicate Weedout + join caching problem. + -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 15:06)=-=- High Level Description modified. --- /tmp/wklog.92.old.22593 2010-02-28 15:06:23.000000000 +0000 +++ /tmp/wklog.92.new.22593 2010-02-28 15:06:23.000000000 +0000 @@ -1 +1 @@ - +We must fix known subquery semi-join bugs. -=-=(Psergey - Sun, 28 Feb 2010, 15:03)=-=- Title modified. --- /tmp/wklog.92.old.22572 2010-02-28 15:03:51.000000000 +0000 +++ /tmp/wklog.92.new.22572 2010-02-28 15:03:51.000000000 +0000 @@ -1 +1 @@ -Unused +Subqueries backport: fix known semi-join subquery bugs -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency deleted: 91 no longer depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:58)=-=- Dependency created: 91 now depends on 92 -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- High Level Description modified. --- /tmp/wklog.92.old.22267 2010-02-28 14:57:52.000000000 +0000 +++ /tmp/wklog.92.new.22267 2010-02-28 14:57:52.000000000 +0000 @@ -1 +1 @@ -We must fix known semi-join subquery bugs. + -=-=(Psergey - Sun, 28 Feb 2010, 14:57)=-=- Title modified. --- /tmp/wklog.92.old.22249 2010-02-28 14:57:41.000000000 +0000 +++ /tmp/wklog.92.new.22249 2010-02-28 14:57:41.000000000 +0000 @@ -1 +1 @@ -Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE +Unused -=-=(Psergey - Sun, 28 Feb 2010, 14:51)=-=- High Level Description modified. --- /tmp/wklog.92.old.21961 2010-02-28 14:51:06.000000000 +0000 +++ /tmp/wklog.92.new.21961 2010-02-28 14:51:06.000000000 +0000 @@ -1,18 +1 @@ -Consider the following case: - -SELECT * FROM big_table -WHERE oe IN (SELECT ie FROM table_with_few_groups - WHERE ... - GROUP BY group_col) AND ... - -Here the best way to execute the query is: - - Materialize the subquery; - # now run the join: - for each record R1 in materialized table - for each record R2 in big_table such that oe=R1 - pass R2 to output - -Semi-join materialization supports such strategy with SJM-Scan strategy. This WL -entry is about adding support for such strategies for non-semijoin subqueries. - +We must fix known semi-join subquery bugs. -=-=(Psergey - Sun, 28 Feb 2010, 14:03)=-=- Observers changed: Psergey,Igor,Timour DESCRIPTION: We must fix known subquery semi-join bugs. * outer join + semi join problem * Duplicate Weedout + join caching problem. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0