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Re: [Maria-discuss] Pacemaker and mariadb semi-sync
by Pavel Ivanov 23 Aug '17

23 Aug '17

Yes, having processlist while it's hung might be handy. On Tue, Aug 22, 2017 at 3:45 PM, Nils Carlson <nils.carlson(a)ludd.ltu.se> wrote: > On 08/22/2017 10:42 PM, Pavel Ivanov wrote: > >> Can you clarify what SHOW SLAVE STATUS blocks on for you? > > Not really. Basically, just after performing a failover, I run SHOW SLAVE > STATUS on the slave and that can take up to 30 seconds sometimes before the > query returns. Once it does return everything looks like normal. I can try > to dump the thread status maybe. > > /Nils > > > >> On Sun, Aug 20, 2017 at 9:47 AM, Nils Carlson <nils.carlson(a)ludd.ltu.se> >> wrote: >>> >>> Hi Pavel and Kristian, >>> >>> On 08/10/2017 10:58 PM, Pavel Ivanov wrote: >>>> >>>> Note also that you don't want to set rpl_semi_sync_master_enabled='ON' >>>> on all your slaves, it should be set only on the master. With the >>>> setting your slaves' SQL threads will hang waiting for semi-sync ack >>>> as well, and they will hang forever if >>>> rpl_semi_sync_master_wait_no_slave is set to ON too. >>>> >>> Thank you. >>> >>>> On Wed, Aug 9, 2017 at 2:30 AM, Kristian Nielsen >>>> <knielsen(a)knielsen-hq.org> wrote: >>>>> >>>>> Hope this helps, >>> >>> >>> And thank you for all this! >>> >>> I have updated the resource-agent based on this and run some light >>> testing. >>> I will try to write automated tests soon. >>> >>> I was also wondering about one thing, the block SHOW SLAVE STATUS >>> command. >>> Is there any way to ensure this doesn't block? Maybe this is something to >>> suggest to the development mailing list? >>> >>> Thanks again. >>> >>> Cheers, >>> Nils >>> >>> >>>>> - Kristian. >>>>> >>>>> _______________________________________________ >>>>> Mailing list: https://launchpad.net/~maria-discuss >>>>> Post to : maria-discuss(a)lists.launchpad.net >>>>> Unsubscribe : https://launchpad.net/~maria-discuss >>>>> More help : https://help.launchpad.net/ListHelp >>> >>> >

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Re: [Maria-discuss] Pacemaker and mariadb semi-sync
by Pavel Ivanov 23 Aug '17

23 Aug '17

Can you clarify what SHOW SLAVE STATUS blocks on for you? On Sun, Aug 20, 2017 at 9:47 AM, Nils Carlson <nils.carlson(a)ludd.ltu.se> wrote: > Hi Pavel and Kristian, > > On 08/10/2017 10:58 PM, Pavel Ivanov wrote: >> >> Note also that you don't want to set rpl_semi_sync_master_enabled='ON' >> on all your slaves, it should be set only on the master. With the >> setting your slaves' SQL threads will hang waiting for semi-sync ack >> as well, and they will hang forever if >> rpl_semi_sync_master_wait_no_slave is set to ON too. >> > Thank you. > >> On Wed, Aug 9, 2017 at 2:30 AM, Kristian Nielsen >> <knielsen(a)knielsen-hq.org> wrote: >>> >>> Hope this helps, > > > And thank you for all this! > > I have updated the resource-agent based on this and run some light testing. > I will try to write automated tests soon. > > I was also wondering about one thing, the block SHOW SLAVE STATUS command. > Is there any way to ensure this doesn't block? Maybe this is something to > suggest to the development mailing list? > > Thanks again. > > Cheers, > Nils > > >>> >>> - Kristian. >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~maria-discuss >>> Post to : maria-discuss(a)lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~maria-discuss >>> More help : https://help.launchpad.net/ListHelp > >

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[Maria-discuss] connection handling is buggy (HY000/2002): Resource temporarily unavailable)
by Reindl Harald 20 Aug '17

20 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] Pacemaker and mariadb semi-sync
by Nils Carlson 11 Aug '17

11 Aug '17

Hi, I've been working on developing a pacemaker resource-agent for mariadb semi-sync replication. There is a pull request here on github: https://github.com/ClusterLabs/resource-agents/pull/929 I would be very happy for some review (and even testing) of this resource-agent from somebody with expertise in mariadb replication. The general idea is to select the master at startup and failure as the node with the highest GTID. AFTER_SYNC is used to ensure at least one slave will have all the updates. mariadb is started with --log-slave-updates to ensure that slaves log all events, so the binary log on each node should always be complete. The parameter set on each node is as follows: SET GLOBAL rpl_semi_sync_slave_enabled='ON', \ rpl_semi_sync_master_enabled='ON', \ rpl_semi_sync_master_wait_point='AFTER_SYNC', \ gtid_strict_mode='ON', \ sync_binlog=1, \ sync_master_info=1, \ sync_relay_log=1, \ sync_relay_log_info=1; I suspect this may be overkill, but I don't have the competence to judge. I have also found that calling "SHOW SLAVE STATUS;" may take a long time to display data when the slave is very busy (typically replicating after a failure). Is there any way to make sure it doesn't block? All feedback very welcome. Best Regards, Nils Carlson

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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] Debian 9 support for MaxScale
by Martin Toth 03 Aug '17

03 Aug '17

Hi all, I would like to ask if there is some release date for fixing https://jira.mariadb.org/browse/MXS-1292 . Debian 9 should be included as a build target ASAP. I am installing only D9 systems on new servers and I am unable to use builds for MaxScale, so its unusable in D9. Thanks. Martin

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[Maria-discuss] MariaDb 10.2 in RHEL 5.3
by Karthick Subramanian 03 Aug '17

03 Aug '17

Did anyone install the Maria DB 10.2 in RHEL Red Hat Enterprise Linux Server release 5.3 (Tikanga). I am planning to install this in Dev env, its not prod, Shall I try this. Regards, Karthick

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[Maria-discuss] 2nd 2017 Developers Unconference
by Ian Gilfillan 03 Aug '17

03 Aug '17

The 2017 MariaDB Developers Unconference will be our first in Asia, and will be held in Shenzhen, China from 13 November - 17 November. There are 3 related events: 13 November - new contributor day 14-15 November - traditional developers unconference 16-17 November - patch days As always it's free to attend, and open to anyone interested in MariaDB development. Details at https://mariadb.org/2017-2-developers-unconference-and-related-events-shenz…

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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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