TIME_MS column in INFORMATION_SCHEMA.PROCESSLIST

The TIME_MS column in the INFORMATION_SCHEMA.PROCESSLIST table displays the time a thread has been in its current state in milliseconds, offering higher precision than the standard TIME column.

In MariaDB, an extra column TIME_MS was 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 theTIME column is one second).

For details about microseconds support in MariaDB, see microseconds in MariaDB.

The value displayed in the TIME andTIME_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 ofSHOW FULL PROCESSLIST andINFORMATION_SCHEMA.PROCESSLIST cannot be used to determine if a slave is lagging behind. For this, use instead theSeconds_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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