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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