July 2017 - discuss - lists.mariadb.org

[Maria-discuss] explain for insert/update/delete
by MARK CALLAGHAN 11 Jul '25

11 Jul '25

Does MariaDB have any plans to support explain for insert/update/delete/replace/CTAS? There have been feature requests open for a very long time on official MySQL without any progress. I have had a few problems in production from 'bad' delete statements that had a very different plan than the select statement with the same where clause. The only way to check for a bad plan today is to use SHOW INNODB STATUS to determine whether the statement locks all rows in a table. http://bugs.mysql.com/bug.php?id=14745 http://bugs.mysql.com/bug.php?id=35355 -- Mark Callaghan mdcallag(a)gmail.com

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[Maria-discuss] Galera 23.2.7 mariadb 5.5.33a msvc 1600 binaries available
by Yann Nayn 21 May '25

21 May '25

Binaries have been uploaded for both x86 and amd64 platforms. due to github file size limitations , the directories have been uploaded unarchived. for Win33 binaries , please checkout https://github.com/YannNayn/galera-mariadb-win32.git and for Win64(amd64) binaries (being uploaded/pushed): https://github.com/YannNayn/galera-mariadb-win64.git they are not recommended for a production environment. in the my.cnf file: _________ wsrep_provider=galera_smm.dll wsrep_sst_method=msqldump # percona xtrabackup will be tested soon _________ libevent and openssl(the provided binaries use respectively 2.1.3-alpha and 1.1.0-dev versions ) will be added next on github some limitations are stated on openssl website copied here for convenience: ____________ from http://www.openssl.org/ ____________ This software package uses strong cryptography, so even if it is created, maintained and distributed from liberal countries in Europe (where it is legal to do this), it falls under certain export/import and/or use restrictions in some other parts of the world. PLEASE REMEMBER THAT EXPORT/IMPORT AND/OR USE OF STRONG CRYPTOGRAPHY SOFTWARE, PROVIDING CRYPTOGRAPHY HOOKS OR EVEN JUST COMMUNICATING TECHNICAL DETAILS ABOUT CRYPTOGRAPHY SOFTWARE IS ILLEGAL IN SOME PARTS OF THE WORLD. SO, WHEN YOU IMPORT THIS PACKAGE TO YOUR COUNTRY, RE-DISTRIBUTE IT FROM THERE OR EVEN JUST EMAIL TECHNICAL SUGGESTIONS OR EVEN SOURCE PATCHES TO THE AUTHOR OR OTHER PEOPLE YOU ARE STRONGLY ADVISED TO PAY CLOSE ATTENTION TO ANY EXPORT/IMPORT AND/OR USE LAWS WHICH APPLY TO YOU. THE AUTHORS OF OPENSSL ARE NOT LIABLE FOR ANY VIOLATIONS YOU MAKE HERE. SO BE CAREFUL, IT IS YOUR RESPONSIBILITY. ________________________________________________ msvc 1600 redistributables SP1 need to be installed/available on the target machine: vcredist_x86.exe : http://www.microsoft.com/en-us/download/details.aspx?id=8328 vcredist_x64.exe : http://www.microsoft.com/en-us/download/details.aspx?id=13523 MSys binaries are provided and msqld.bat should then be used instead of mysqld.exe (e.g. mysld.bat --console --wsrep_cluster_address=gcomm:// ) in order to have a working sh shell(cygwin has been proved to do it as well) Please note that oqgraph is disabled (boost trunk is used , that is 1.55) Comments and suggestions are welcome.

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[Maria-discuss] why stdout? -> [Note] /usr/libexec/mysqld (mysqld 10.0.20-MariaDB) starting as process 115096
by Reindl Harald 05 Jul '20

05 Jul '20

Aug 6 12:24:24 testserver mysqld: 150806 12:24:24 [Note] /usr/libexec/mysqld (mysqld 10.0.20-MariaDB) starting as process 115096 ... why is this now stdout instead mysql logs? on systemd based distributions that spits now to the global syslog and finally on machines restarting 2 instances every hour for backup reasons it annoys until 10.0.19 or 10.0.20 that was not this way

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[Maria-discuss] Charsets and collations
by Peter Laursen 20 Apr '18

20 Apr '18

Does anybody know if there are any plans to bring collations added in MySQL 8 - refer http://mysqlserverteam.com/new-collations-in-mysql-8-0-0/ - to MariaDB and are there any plans to change the default charset to a unicode-based one? -- Peter -- Webyog

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[Maria-discuss] connection handling is buggy (HY000/2002): Resource temporarily unavailable)
by Reindl Harald 19 Aug '17

19 Aug '17

i started to play around with "thread_handling = pool-of-threads" with 10.2.7 and removed at that time the @mysqli_real_connect() error supression of my database-layer which also has a usleep() and retry-loop in case connection failed on so completly burried the issue PHP Warning: mysqli_real_connect() [<a href='http://at.php.net/manual/de/function.mysqli-real-connect.php'>function.mysqli-real-connect.php</a>]: (HY000/2002): Resource temporarily unavailable you should not see such messages when run a "ab -c 200 -n 500000 -k http://corecms/show_content.php?sid=2" with "max_connections = 300" _____________________________________ thread_handling = one-thread-per-connection [root@srv-rhsoft:~]$ cat php_error.log | wc -l 52596 thread_handling = pool-of-threads thread_pool_idle_timeout = 900 [root@srv-rhsoft:~]$ cat php_error.log | wc -l 39282 thread_handling = pool-of-threads thread_pool_oversubscribe = 10 thread_pool_idle_timeout = 900 thread_pool_priority = high [root@srv-rhsoft:~]$ cat php_error.log | wc -l 24849 since my database-layer makes a usleep(100000) before each retry and the retry-lop still has error-supression that means the cms waits 10% of all requests at least 0.1 seconds for the mariadb server which means the 4300 Requests/Second could be much higher if every connection suceeds at the first try (at least the thread pool seems to work slightly better then without) _____________________________________ what makes me really worry here is while the load is running (mysqld each time restartet before start apache-benchmark) +-------------------------+-------+ | Variable_name | Value | +-------------------------+-------+ | Threadpool_idle_threads | 181 | | Threadpool_threads | 189 | +-------------------------+-------+ after the benchmark has finished and the machine is idle: +-------------------------+-------+ | Variable_name | Value | +-------------------------+-------+ | Threadpool_idle_threads | 207 | | Threadpool_threads | 208 | +-------------------------+-------+ frankly i would expect at least that this numbers are going up while the load is running to at least 200 or not going up that high at all but don't refuse conncetions which is IMHO the point of a pool _____________________________________ the core-cms itself makes exactly two queries per request over 3 MyISAM tables, one cache-table with a pirmary key and the second one is a simple join on two tables with only 2 records, so not really something one should call real load select SQL_NO_CACHE * from cms1_cache where `hash`='fullmenu_1_2_0de0_0' select SQL_NO_CACHE * from `cms1_sub` join `cms1_haupt` on sid=2 and hid=shid mysqld as well as httpd had "LimitNOFILE=infinity" in the systemd-unit, the connection type is unix socket, so that all should not be a problem on a i7-3770 CPU @ 3.40GHz with 32 GB RAM it takes some time until the errors start to appear in the log, likely after httpd (mod_prefork) had forked enough worker to introduce real concurrency to the database

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[Maria-discuss] question about fast path for TRUNCATE TABLE
by MARK CALLAGHAN 06 Aug '17

06 Aug '17

This started as a question on a MyRocks list. MyRocks comes from MariaDB in this case and the code that determines whether the truncate table fast path is used looks different in MariaDB than in FB MySQL. By "fast path" for truncate I mean the use of drop/recreate for truncate. The slow path is delete one row at a time. In this case, truncate is doing delete one row at a time for MyRocks in MariaDB but drop/recreate in FB MySQL. https://groups.google.com/forum/#!topic/myrocks-dev/dhweTwN-9xg -- Mark Callaghan mdcallag(a)gmail.com

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[Maria-discuss] Tokudb 5.7.18-16 fixes in Mariadb 10.2.8
by Reinis Rozitis 02 Aug '17

02 Aug '17

Hello, is there any chance/possibility for these fixes from Percona Server 5.7.18-16 to land in 10.2.8 release? Row counts in TokuDB could be lost intermittently after restarts ( https://jira.percona.com/browse/TDB-2 ) In TokuDB, two races in the fractal tree lock manager .. ( https://jira.percona.com/browse/TDB-3 ) rr

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[Maria-discuss] 10.2.7 - Specified key was too long; max key length is 1000 bytes
by Reindl Harald 31 Jul '17

31 Jul '17

what the hell is this when the MYISAM database has a utf8 charset while this don't happen with latin1_german1_ci - this seems to be a regression in 10.2 and wasted an hour of time to realize what is going on just because anotehr guy did not take care of the database charset create table `cms1_formmailer_generic_cc` (`fg_key` mediumint(7) unsigned not null auto_increment, `fg_form` varchar(255) not null default '', `fg_email` varchar(255) not null default '', primary key(`fg_key`), key`fg_key` (`fg_form`, `fg_email`)) - Specified key was too long; max key length is 1000 bytes

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[Maria-discuss] MariaDB unable to read the /etc/krb5.keytab
by Ali, Saqib 24 Jul '17

24 Jul '17

I am trying to setup MariaDB 10 with GSSAPI support. I following the instructions here: https://mariadb.com/kb/en/mariadb/gssapi-authentication-plugin/ However, whenever I try to start Maria DB I get the following [Warning] mysqld: GSSAPI plugin : default principal 'mariadb/hostname.tld@REALM' not found in keytab [ERROR] mysqld: Server GSSAPI error (major 851968, minor 2529639093) : gss_acquire_cred failed -Unspecified GSS failure. Minor code may provide more information. Keytab FILE:/etc/krb5.keytab is nonexistent or empty. [ERROR] Plugin 'gssapi' init function returned error. Sincerely, Saqib http://saqib.org

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[Maria-discuss] TokuDB performance hit after 10.0.25
by Alessandro Ren 24 Jul '17

24 Jul '17

Hello, I've noticed a great performance hit after I upgraded my MariaDB install to 10.0.28, 10.0.29, 10.0.30 and 10.0.31. I even tried upgrading to MariaDB 10.2.7 and had the same problem. Bellow de details. MariaDB 10.0.25 - 13 rows in set (1.67 sec) MariaDB 10.0.31 - 13 rows in set (29.06 sec) The query: SELECT metric_id,date_format(entry_time, '%m:%Y') as date_group, unix_timestamp(entry_time) as entry_time, entry_time as datetime, avg(perf_value) as perf_value, warning, critical, baseline, lower_limit, upper_limit from service_perf_651 where service_id='56551' and metric_id='90183701' and entry_time>='2016-07-24 09:41:42' and entry_time<='2017-07-24 09:41:42' and ( (date_format(entry_time,'%w')=0 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H') < 24))) or (date_format(entry_time,'%w')=1 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) or (date_format(entry_time,'%w')=2 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) or (date_format(entry_time,'%w')=3 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) or (date_format(entry_time,'%w')=4 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) or (date_format(entry_time,'%w')=5 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) or (date_format(entry_time,'%w')=6 and ((date_format(entry_time,'%H')>=0 and date_format(entry_time,'%H')<24) )) ) group by date_group order by entry_time Explain query: +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+ | 1 | SIMPLE | service_perf_651 | range | PRIMARY,service_perf_1_idx | PRIMARY | 16 | NULL | 1 | Using where; Using temporary; Using filesort | +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+ 1 row in set (0.06 sec) The table: CREATE TABLE `service_perf_651` ( `entry_time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00', `service_id` int(11) unsigned NOT NULL DEFAULT '0', `metric_id` int(11) unsigned NOT NULL DEFAULT '0', `perf_value` float(13,3) DEFAULT NULL, `warning` float(13,3) DEFAULT NULL, `critical` float(13,3) DEFAULT NULL, `baseline` float(13,3) DEFAULT NULL, `lower_limit` float(13,3) DEFAULT NULL, `upper_limit` float(13,3) DEFAULT NULL, `reserved0` float(13,3) DEFAULT NULL, `reserved1` float(13,3) DEFAULT NULL, `reserved2` float(13,3) DEFAULT NULL, PRIMARY KEY (`entry_time`,`service_id`,`metric_id`), KEY `service_perf_1_idx` (`service_id`,`metric_id`,`entry_time`) ) ENGINE=TokuDB DEFAULT CHARSET=utf8 `compression`='tokudb_snappy' The size: 32497415 records Any idea what could be wrong? I even tried everything above on a different HW where the databse fit in memory in TokuDB, with the same performance hit. Tks for the help Alessandro Ren

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