In MariaDB, an extra column TIME_MS
has been added to the INFORMATION_SCHEMA.PROCESSLIST table. This column shows the same information as the column 'TIME
', but in units of milliseconds with microsecond precision (the unit and precision of the TIME
column is one second).
For details about microseconds support in MariaDB, see microseconds in MariaDB.
The value displayed in the TIME
and TIME_MS
columns is the period of time that the given thread has been in its current state. Thus it can be used to check for example how long a thread has been executing the current query, or for how long it has been idle.
select id, time, time_ms, command, state from information_schema.processlist, (select sleep(2)) t; +----+------+----------+---------+-----------+ | id | time | time_ms | command | state | +----+------+----------+---------+-----------+ | 37 | 2 | 2000.493 | Query | executing | +----+------+----------+---------+-----------+
Note that as a difference to MySQL, in MariaDB the TIME
column (and also the TIME_MS
column) are not affected by any setting of @TIMESTAMP. This means that it can be reliably used also for threads that change @TIMESTAMP
(such as the replication SQL thread). See also MySQL Bug #22047.
As a consequence of this, the TIME
column of SHOW FULL PROCESSLIST
and INFORMATION_SCHEMA.PROCESSLIST
can not be used to determine if a slave is lagging behind. For this, use instead the Seconds_Behind_Master
column in the output of SHOW SLAVE STATUS.
The addition of the TIME_MS column is based on the microsec_process patch, developed by Percona.
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Licensed under the Creative Commons Attribution 3.0 Unported License and the GNU Free Documentation License.
https://mariadb.com/kb/en/time_ms-column-in-information_schemaprocesslist/