Hello Karl. Thanks for your help. Unfortunately, we have many databases with many MyISAM tables.... I guess we can't use the --no-lock option. Kind Regards Riccardo 15/06/2021, 18:43 Karl Levik ha scritto:
Hi Riccardo,
Are you able to use the --no-lock option?
According to "mariabackup --help":
--no-lock Use this option to disable table lock with "FLUSH TABLES
WITH READ LOCK". Use it only if ALL your tables are
InnoDB and you DO NOT CARE about the binary log position
of the backup. This option shouldn't be used if there are
any DDL statements being executed or if any updates are
happening on non-InnoDB tables (this includes the system
MyISAM tables in the mysql database), otherwise it could
lead to an inconsistent backup. If you are considering to
use --no-lock because your backups are failing to acquire
the lock, this could be because of incoming replication
events preventing the lock from succeeding. Please try
using --safe-slave-backup to momentarily stop the
replication slave thread, this may help the backup to
succeed and you then don't need to resort to using this
option.
Cheers,
Karl
On Tue, 15 Jun 2021 at 14:00, Riccardo Brunetti <riccardo.brunetti@host.it> wrote:
Hello.
We are using the mariabackup tool to stream to a remote server the backup of our databases.
We are having some issue because in the middle of the operation the db server stops responding for many minutes until we ultimately kill the mariabackup process.
During the lock, we can see the following:
MariaDB [(none)]> show processlist;
+--------+----------------------------+-----------------+--------------------------+---------+------+------------------------------+------------------------------------------------------------------------------------------------------+----------+
| Id | User | Host | db | Command | Time | State | Info | Progress |
+--------+----------------------------+-----------------+--------------------------+---------+------+------------------------------+------------------------------------------------------------------------------------------------------+----------+
| 3 | system user | | NULL | Daemon | NULL | InnoDB purge worker | NULL | 0.000 |
| 4 | system user | | NULL | Daemon | NULL | InnoDB purge worker | NULL | 0.000 |
| 1 | system user | | NULL | Daemon | NULL | InnoDB purge coordinator | NULL | 0.000 |
| 2 | system user | | NULL | Daemon | NULL | InnoDB purge worker | NULL | 0.000 |
| 5 | system user | | NULL | Daemon | NULL | InnoDB shutdown handler | NULL | 0.000 |
| 274355 | root | localhost:42512 | NULL | Sleep | 407 | | NULL | 0.000 |
| 297631 | udaww4uw_gsut | localhost:39784 | udaww4uw_gsprod | Query | 17 | Waiting for global read lock | UPDATE `wp_litespeed_crawler` SET reason = CONCAT( SUBSTRING_INDEX( reason, ',', 0 ), '200', SUBSTRI | 0.000 |
| 302083 | ud4k9xsm_pres633 | localhost | ud4k9xsm_pres633 | Query | 47 | Waiting for global read lock | DELETE FROM `ps4d_marketplace_product_action`
WHERE `id_product` = 7356 AND `id_lan | 0.000 |
| 302391 | udaww4uw_gsut | localhost:50748 | udaww4uw_gsprod | Query | 46 | Waiting for global read lock | INSERT INTO wp_post_views (id, type, period, count)
VALUES (62075, 3, '2021', 1)
ON DUPLIC | 0.000 |
| 302395 | uqlugtoj_enedina.it | localhost | uqlugtoj_enedina | Query | 44 | Waiting for global read lock | UPDATE `wp_options` SET `option_value` = '1623829414' WHERE `option_name` = '_transient_timeout_wc_r | 0.000 |
| 302404 | udlah5r1_remigio | localhost:50782 | udlah5r1_vtiger71 | Query | 44 | Waiting for global read lock | insert into vtiger_pbxmanager(pbxmanagerid,direction,callstatus,starttime,endtime,totalduration,bill | 0.000 |
| 302431 | utlmb6ko_6M0oD0 | localhost | utlmb6ko_6M0oD0 | Query | 38 | Waiting for global read lock | UPDATE `wp_options` SET `option_value` = '1623743080' WHERE `option_name` = 'action_scheduler_lock_a | 0.000 |
| 302432 | uml1gkxr_58IJ3 | localhost:50836 | uml1gkxr_prod | Query | 38 | Waiting for global read lock | UPDATE `wp_options` SET `option_value` = 'a:13835:{i:1226;s:32:\"ab7050de2954be1e369e358a15a17c48\"; | 0.000 |
| 302433 | uml1gkxr_58IJ3 | localhost:50838 | uml1gkxr_prod | Query | 38 | Waiting for global read lock | UPDATE `wp_options` SET `option_value` = 'a:13835:{i:1226;s:32:\"ab7050de2954be1e369e358a15a17c48\"; | 0.000 |
| 302440 | uqtx0c94_giorgio | localhost:50848 | uqtx0c94_due | Query | 38 | Waiting for global read lock | UPDATE `wp_options` SET `option_value` = '[]' WHERE `option_name` = '_transient_adsforwp_transient_a | 0.000 |
| 302473 | uw6vnwff_helpdesk | localhost:50932 | uw6vnwff_helpassist | Query | 30 | Waiting for global read lock | INSERT INTO ost_syslog SET created=NOW(), updated=NOW() ,title='DB Error #1205',log_type='Error',log | 0.000 |
At the same time, we see messages like these in the system log:
Executing FLUSH NO_WRITE_TO_BINLOG TABLES...
Executing FLUSH TABLES WITH READ LOCK...
This is the command we launch to backup data:
mariabackup --backup --stream=xbstream --user=root --extra-lsndir=${BCKDBDIR} -u${MYSQLUSER} -p${MYSQLPW} -H ${MYSQLHOST}"
Is it somehow an expected behavior (some of the db are quite heavily used)?
How can we avoid those locks?
Thanks
Riccardo
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