mariadb 10.1查看per connection内存消耗
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在mariadb 10.1版本中,在information_schema.processlist表中,新增了几个字段,其中有一个memory_used,其记录的是连接的内存消耗。
同时新增了一个状态变量memory_used,其记录的应该是所有连接加起来消耗的内存(官方并没有特别详细地解释https://mariadb.com/kb/en/mariadb/show-processlist/),应该类似于oracle pga的概念。
为了再检查下mysql占用内存远超过buffer pool的原因,我们特地让运维将某个线上实例从percona切换到了mariadb 10.1.21进行观察。如下:
[root@iZbp13xgu1d7hpg1gca4ndZ ~]# mysql -uroot -pmysql Welcome to the MariaDB monitor. Commands end with ; or \\g. Your MariaDB connection id is 1046786 Server version: 10.1.20-MariaDB MariaDB Server Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others. Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement. MariaDB [(none)]> show status like \'%memory_used%\'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | Memory_used | 67464 | +---------------+-------+ 1 row in set (0.00 sec) MariaDB [(none)]> show global status like \'%memory_used%\'; +---------------+-----------+ | Variable_name | Value | +---------------+-----------+ | Memory_used | 568761128 | +---------------+-----------+ 1 row in set (0.00 sec) MariaDB [(none)]> select user,host,memory_used from information_schema.processlist; +-----------------+----------------------+-------------+ | user | host | memory_used | +-----------------+----------------------+-------------+ | root | localhost | 84576 | | osm | 10.253.106.167:47847 | 95376 | | osm | 10.253.106.167:47843 | 94616 | | osm | 10.253.106.167:47845 | 94224 | | osm | 10.253.106.167:47841 | 93856 | | osm | 10.253.106.167:47835 | 94224 | | osm | 10.253.106.167:47836 | 94616 | | osm | 10.253.106.167:47831 | 67464 | | osm | 10.253.106.167:47832 | 67464 | | osm | 10.253.106.167:47815 | 71312 | | osm | 10.253.106.167:47791 | 67464 | | osm | 10.253.106.167:47792 | 67464 | | osm | 10.253.106.167:47780 | 67464 | | event_scheduler | localhost | 39784 | +-----------------+----------------------+-------------+ 14 rows in set (0.00 sec)
在其内存输出中,没有办法得出global memory_used是如何组成的?processlist汇总起来也不是这个值,这确实比较奇怪,官方和各种forum也没找到各种解释。。。
该服务器buffer pool配置的是4GB,外有一些临时表在用,当前的进程内存消耗如下:
所以,就算4GB+memory_used也差不多4.55G差不多,和实际的6.4G差距还是蛮大的,看来mysql在这方面还是需要有较大的改进。
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