November 2017 - developers - lists.mariadb.org

[Maria-developers] Windows line endings in MariaDB sources again (
by Otto Kekäläinen 24 Jul '19

24 Jul '19

Hello! While trying to release 10.0.26 for Debian and Ubuntu I noticed git chokes again on Windows line endings. As our .gitattributes states that by default git should clean up the line endings, why do we keep getting new Windows line endings in new code? mariadb-10.0$ cat .gitattributes # Set the default behavior, in case people don't have core.autocrlf set. * text=auto ... storage/connect/mysql-test/connect/std_data/*.txt -text mariadb-10.0.26$ find . | xargs file | grep CRLF ./storage/connect/mysql-test/connect/std_data/boyswin.txt: ASCII text, with CRLF line terminators ./storage/connect/mysql-test/connect/std_data/expenses.txt: ASCII text, with CRLF line terminators ./storage/connect/mysql-test/connect/std_data/emp.txt: ASCII text, with CRLF line terminators ./mysql-test/std_data/loaddata7.dat: ASCII text, with CRLF line terminators ./mysql-test/r/loadxml.result: ASCII text, with CRLF, LF line terminators ./mysql-test/r/perror-win.result: ASCII text, with CRLF, LF line terminators ./mysql-test/r/mysql_binary_mode.result: ASCII English text, with CRLF, LF line terminators ./mysql-test/r/func_regexp_pcre.result: UTF-8 Unicode C++ program text, with CRLF, CR, LF line terminators ./pcre/testdata/grepoutputN: ASCII text, with CRLF, CR, LF line terminators ./pcre/testdata/greppatN4: ASCII text, with CRLF line terminators This leads for me to: dpkg-source: info: building mariadb-10.0 using existing ./mariadb-10.0_10.0.26.orig.tar.gz dpkg-source: info: local changes detected, the modified files are: mariadb-10.0/storage/connect/mysql-test/connect/std_data/boyswin.txt mariadb-10.0/storage/connect/mysql-test/connect/std_data/emp.txt mariadb-10.0/storage/connect/mysql-test/connect/std_data/expenses.txt dpkg-source: error: aborting due to unexpected upstream changes, see /tmp/mariadb-10.0_10.0.26-1.diff.Yzwwhw Which means I have to do extra work with importing the upstream sources.. - Otto

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[Maria-developers] 10.2 and merges (e.g. TokuDB)
by Phil Sweeney 28 Aug '18

28 Aug '18

Hi there, It seems 10.2.6 is still shipping with TokuDB from PS 5.6.35-80 (Feb 8th 2017). I can't see a jira issue for a 10.2 merge since 10.2.4. Perhaps intentional to help stabilise 10.2 for release? 10.0.30 also shipped with the same Feb version (in March). 10.1.23 however was released in May and still has this version from Feb, which seems unfortunate, but I know it's because it has to flow through 10.0 first. I see 10.0.31 is due to get TokuDB from PS 5.6.36-82 And that should flow into 10.1.24 soon too. However, 10.2.7 isn't due until July, so by then TokuDB version will be 5 months old in 10.2 I'm waiting on a fairly important row count fix that should appear in the next Percona Server release. When it does, if the current merging strategy continues, do I have to first wait for 10.0.32 to get it in late July, then 10.1.26 in August, then 10.2 after that? Or with 10.0, 10.1 and 10.2 all being supported and needing merges, is there a new strategy on the cards to shorten this lag? Thanks! Phil

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[Maria-developers] MDEV-13118 Wrong results with LOWER and UPPER and subquery
by Alexander Barkov 12 Jul '18

12 Jul '18

Hello Sergei, Please review a patch for MDEV-13118. Thanks!

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Re: [Maria-developers] Mdev-10664 Add statuses about optimistic parallel replication stalls.
by Sachin Setiya 19 Apr '18

19 Apr '18

Hi Kristian! Sorry for late reply , I was on vacations. On Tue, Jan 10, 2017 at 7:31 PM, Kristian Nielsen <knielsen(a)knielsen-hq.org> wrote: > Sachin Setiya <sachin.setiya(a)mariadb.com> writes: > > >> Right, but you still need _some_ way to synchronise multiple threads > > > I used atomic builtins my_atomic_add64_explicit. > > That seems fine (but see comment below). > > > Documentation:- > > > > Slave_DDL_Events:- > > > > Description: Number of DDL statements slave have executed in > > replication channel X. > > Scope: Per Replication Channel > > Data Type: numeric > > Introduced: MariaDB 10.1 > > > > Slave_Non_Transactional_Events:- > > > > Description: Number of Non Transactional "no idea what should be the > > next word " slave have executed in replication channel X. > > Scope: Per Replication Channel > > Data Type: numeric > > Introduced: MariaDB 10.1 > > I checked, the term "event group" is used already multiple places in the > documentation, so I think it can be used here also. An event group can be a > transaction (possibly with multiple transactional DML statements), or a DDL > or non-transactional statement. > > What you are doing is introducing status variables to help understand > optimistic (and aggressive) parallel replication modes. > > In optimistic parallel replication, a non-transactional event group is not > safe to run in parallel with other non-transactional events. So that event > is made to wait for all prior event groups to reach commit state, before > being allowed to execute. However, other transactional events are not > delayed by the non-transactional event group. > > Slave_Non_Transactional_Events counts the occurences of this. > > Then in case of a DDL statement, this can potentially be unsafe to run in > parallel even with other transactional events. So for a DDL, the DDL has to > wait for all prior event groups, _and_ subsequent event groups have to wait > for the DDL. > > Slave_DDL_Events counts these occurences. > > This is what the documentation, and commit messages, should explain, I > think. > > I think the status variables describe the values for > @@default_master_connection?, this should also be explained in the > documentation. > > Why did you decide to put this information into a status variable? > Normally, > slave status is seen in SHOW SLAVE STATUS, which supports showing status > for > a particular connection without using @@default_master_connection. > > Sorry for this , I guess It was a confusion I was looking at Slave_Running this is avaliable in show status as well as show slave status. So I thought for if I want to show some information in SHOW slave status this has to be in show status. And this is wrong. Now we can see non trans events / ddl events in show slave status. Show I remove this vars from Show Status, or it is okay ? > > diff --git a/sql/log_event.h b/sql/log_event.h > > index 90900f6..579607f 100644 > > --- a/sql/log_event.h > > +++ b/sql/log_event.h > > @@ -50,6 +50,7 @@ > > #endif > > > > #include "rpl_gtid.h" > > +#include "my_atomic.h" > > Why include my_atomic.h in the header file, when you only use it in the .cc > file? > Changed. > > > + mysql_mutex_lock(&LOCK_active_mi); > > + if (master_info_index) > > + { > > + mi= master_info_index-> > > + get_master_info(&thd->variables.default_master_connection, > > + Sql_condition::WARN_LEVEL_NOTE); > > + if (mi) > > + tmp= mi->total_ddl_events; > > > + if (mi) > > + tmp= mi->total_non_trans_events; > > Better use an atomic primitive here to read the value. Taking a mutex does > not help synchronise against my_atomic_add64_explicit(). > > Changed. > > + } > > + mysql_mutex_unlock(&LOCK_active_mi); > > + if (mi) > > + *((longlong *)buff)= tmp; > > + else > > + var->type= SHOW_UNDEF; > > + > > + return 0; > > +} > > #endif /* HAVE_REPLICATION */ > > > > static int show_open_tables(THD *thd, SHOW_VAR *var, char *buff, > > > index 9365c06..a474aa5 100644 > > --- a/sql/rpl_mi.h > > +++ b/sql/rpl_mi.h > > @@ -303,6 +303,12 @@ class Master_info : public > Slave_reporting_capability > > > > /* The parallel replication mode. */ > > enum_slave_parallel_mode parallel_mode; > > + > > + /* No of DDL statements */ > > + long total_ddl_events; > > + > > + /* No of non-transactional statements*/ > > + long total_non_trans_events; > > "long" is not the appropriate type here. Certainly not since you are using > my_atomic_add64_explicit(). Use a type that is the same size on all > platforms (and why use a signed type?). > > Changed to uint64. > - Kristian. > Attached a newer version of patch , please review it. -- Regards Sachin

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[Maria-developers] CREATE SEQUENCE is coming
by Michael Widenius 18 Apr '18

18 Apr '18

Hi! For those that are trying to port applications to MariaDB from other databases or need more features than the current AUTO_INCREMENT provides, the following may be of interest: First version of sequence is pushed to bb-10.2-sequence. It should be merged to bb-10.2-compatilbity and then to 10.3 shortly (1-2 weeks). What is working for the moment: CREATE OR REPLACE [TEMPORARY] SEQUENCE [IF NOT EXISTS] name [ INCREMENT [ BY | = ] increment ] [ MINVALUE [=] minvalue | NO MINVALUE ] [ MAXVALUE [=] maxvalue | NO MAXVALUE ] [ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ] ENGINE=xxx COMMENT=".." SELECT NEXT VALUE FOR sequence_name; SELECT NEXTVAL(sequence_name); SELECT PREVIOUS VALUE FOR sequence_name; SELECT LASTVAL(sequence_name); SHOW CREATE SEQUENCE sequence_name; SHOW CREATE TABLE sequence_name; CREATE TABLE sequence-structure ... SEQUENCE=1 ALTER TABLE sequence RENAME TO sequence2; RENAME TABLE sequence RENAME TO sequence2; DROP [TEMPORARY] SEQUENCE sequence_name [IF EXISTS] See https://jira.mariadb.org/browse/MDEV-10139 for progress. See commit messages in bb-10.2-sequence for what is still to be done. Some documentation can be found at: https://mariadb.com/kb/en/mariadb/create-sequence/ This will be improved as the work progress. One of the goals with the SEQUENCE implementation is that all old tools, like mysqldump, should work unchanged, while still keeping normal usage of sequence standard compatibly. The make this possible, the sequence is currently implemented as a table with a few exclusive properties. The main disadvantage of having sequence as a table is that it uses the same name space as tables. In other words, you can't have a table and a sequence of the same name. The benefit is that sequences shows up in 'show tables', one can create a sequence also with 'create table' and drop it with 'drop table'. One can select from it as from any other table. This ensures that all old tools that works with tables should work with sequences. The special properties for sequence tables are: - A sequence table has always one row. - When one creates a sequence, either with CREATE TABLE or CREATE SEQUENCE, one row will be inserted. - Normal table options works for CREATE SEQUENCE. One can use ENGINE=xxx, COMMENT=xxx etc. - If one tries to insert into a sequence table, the single row will be updated. This allows mysqldump to work but also gives the additional benefit that one can change all properties of a sequence with a single insert. New applications can of course also use ALTER SEQUENCE. - Updates to the sequence table will change the single row. - Doing a select on the sequence shows the current state of the sequence, except the values that are reserved in the cache. The column 'next_value' shows the next value not reserved by the cache. - Truncate on a sequence table will give an error. - Alter table and rename works on sequences. - If one creates a sequence with INCREMENT 0, then the sequence will use auto_increment_increment and auto_increment_offset for the sequence, just like AUTO_INCREMENT. This allows sequences to work reliable in a master-master environment and with Galera. Internally sequence tables are created as a normal table without rollback (InnoDB, Aria and MySAM supports this) with is wrapped by a sequence engine. This allowed me to create sequences with almost no performance impact for normal tables. (The cost is one 'if' per insert if binary log is enabled). MariaDB 10.3 will support both the ANSI SQL and Oracle syntax for creating and accessing sequences. As ANSI SQL doesn't have an easy access to the last generated value, 103 also supports 'PREVIOUS VALUE FOR sequence_name', like IBM DB2, and LASTVAL(sequence_name) as PostgreSQL. I want to thank Jianwe Zhao from Aliyun for his work on SEQUENCE in AliSQL which gave me ideas and inspiration for this work. I also want to thank Marko Mäkelä for his help in the InnoDB part of the code. There is still a lot of work to fix edge cases, but in the current implementation most major things seams to work... Comments, suggestions or questions? Regards, Monty

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[Maria-developers] MDEV-13790 UNHEX() of a somewhat complicated CONCAT() returns NULL
by Alexander Barkov 29 Jan '18

29 Jan '18

Hello Sergei, Please review a patch for MDEV-13790. It removes the attempt to search the best suitable buffer and just returns the result in "str" passed to val_str(). I'm quite sure this optimization gives nothing. In can be useful only under very rare conditions, but generates so many bugs. Moreover, in 10.3 (or 10.4) we'll work on reentrant items. So all Item_xxx::tmp_buffer will be gone anyway, together with this optimization. I think an optimization proposal. Why not to introduce a new method: class Item { public: .. virtual append_to_string(String *str); .. } So for example Field_varchar could write directly to "str" passed to Item_func_concat::val_str(). This will make sure that the first allocation is done on the target "str", and "str" will always be the best buffer instead of any Item_xxx::tmp_value. Thanks!

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[Maria-developers] a doubt about locks on supremum
by hongxiang jiang 18 Jan '18

18 Jan '18

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[Maria-developers] Fwd: Need Help
by Deepak Gupta 20 Dec '17

20 Dec '17

Hi There, I am working on a project where I have some wired requirement for my project. Issue : I am looking for the generic script that I can run with the help of Admin rights on the data base and I want the return output in such a way that it will give me the complete data base structure along with the table relation ship. For an example , there is one HR schema , with in that schema there might be 100 tables example , Employee / Salary / Address / Department etc and every table has primary and foreign key concept. So I need the script should be such a way that it will fetch all these information and as soon as I run the same script in my local system it will replicate the same data base structure for me in my local system. Kindly suggest how can I achieve this requirement ? Any help or suggestions are more than welcome. Looking foreword to here you soon. Thanks D

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[Maria-developers] Review for MDEV-8320 Allow index usage for DATE(datetime_column) = const
by Alexander Barkov 30 Nov '17

30 Nov '17

Hello Sergey, I generally like your patch for MDEV-8320: http://lists.askmonty.org/pipermail/commits/2017-November/011680.html However, there is one problem with it. We're changing the code to have data type plugins. Every data type plugin will provide its own list of SQL functions. Those data type specific functions should be able to use the same optimization approach without having to change the server code. Therefore, everything related to YEAR(field) transformation should reside inside Item_func_year, everything related to DATE(field) transformation should reside inside Item_date_typecast. I reorganized the code to implement this idea. Note, also I changed the logic behind DATE(indexed_date_field) transformation slightly. The DATE() just gets removed. DATE(indexed_date_field) = const is changed to: indexed_date_field = const instead of: indexed_date_field BETWEEN ... AND ... Please have a look: sargable_date_cond.result is slightly different in my version. Greetings.

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[Maria-developers] Delete vs multi_delete performance issue
by jerome brauge 29 Nov '17

29 Nov '17

Hi All, I've a question on kind of delete on whose we have performance issues. Consider two tables: CREATE TABLE `gapfl` ( `pgegapfl` varchar(150) COLLATE utf8_bin NOT NULL, `blkgapfl` varchar(30) COLLATE utf8_bin NOT NULL, `fldgapfl` varchar(30) COLLATE utf8_bin NOT NULL, `ordgapfl` int(11) NOT NULL, ... `stlgapfl` varchar(30) COLLATE utf8_bin DEFAULT NULL, UNIQUE KEY `gapfl_fld` (`pgegapfl`,`blkgapfl`,`fldgapfl`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin and CREATE TABLE `gapge` ( `nuugapge` varchar(150) COLLATE utf8_bin NOT NULL, `nuigapge` int(11) NOT NULL, `frmgapge` varchar(30) COLLATE utf8_bin NOT NULL, `prsgapge` varchar(60) COLLATE utf8_bin NOT NULL, `typgapge` varchar(2) COLLATE utf8_bin NOT NULL, `catgapge` varchar(1) COLLATE utf8_bin NOT NULL, `numgapge` int(11) NOT NULL, `aplgapge` varchar(8) COLLATE utf8_bin DEFAULT NULL, `tragapge` varchar(8) COLLATE utf8_bin DEFAULT NULL, ... `mafgapge` varchar(1) COLLATE utf8_bin NOT NULL, UNIQUE KEY `gapge_nuu` (`nuugapge`), UNIQUE KEY `gapge_frm` (`frmgapge`,`prsgapge`,`typgapge`,`numgapge`,`tragapge`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin Table "gapfl " contains 364740 rows Table "gapge " contains 25423 rows The following delete tooks more than 38 seconds to delete 0 rows . DELETE FROM gapfl WHERE pgegapfl IN ( SELECT nuugapge FROM gapge WHERE frmgapge = 'AMCEVA' AND prsgapge = 'QUALIAC.*.*') It explain plan is : +------+--------------------+-------+-----------------+---------------------+-----------+---------+------+--------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+--------------------+-------+-----------------+---------------------+-----------+---------+------+--------+-------------+ | 1 | PRIMARY | gapfl | ALL | NULL | NULL | NULL | NULL | 356417 | Using where | | 2 | DEPENDENT SUBQUERY | gapge | unique_subquery | gapge_nuu,gapge_frm | gapge_nuu | 452 | func | 1 | Using where | +------+--------------------+-------+-----------------+---------------------+-----------+---------+------+--------+-------------+ It's not really good and I don't understand why the subselect is consider as a "DEPENDENT SUBQUERY" (there is no correlation columns). Now, I convert this delete into a multi_delete : DELETE gapfl FROM gapfl WHERE pgegapfl IN ( SELECT nuugapge FROM gapge WHERE frmgapge = 'AMCEVA' AND prsgapge = 'QUALIAC.*.*') It tooks 0.00 second and it explain plan is : +------+-------------+-------+------+---------------------+-----------+---------+--------------------+------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------+------+---------------------+-----------+---------+--------------------+------+--------------------------+ | 1 | PRIMARY | gapge | ref | gapge_nuu,gapge_frm | gapge_frm | 274 | const,const | 1 | Using where; Using index | | 1 | PRIMARY | gapfl | ref | gapfl_fld | gapfl_fld | 452 | dvt.gapge.nuugapge | 7 | | +------+-------------+-------+------+---------------------+-----------+---------+--------------------+------+--------------------------+ as expected. Is there any way to have the right plan with single delete ? Or do we must convert all our complex update to multi_update ? Sorry if it's not the right place to post this query. Regards.

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