Process List

Process List

This page describes Percona changes to both the standard MySQL SHOW PROCESSLIST command and the standard MySQL INFORMATION_SCHEMA table PROCESSLIST.

The changes that have been made as of version 5.5 of the server are:

  • SHOW PROCESSLIST command:
    • added columns ROWS_EXAMINED, ROWS_SENT, and ROWS_READ
  • PROCESSLIST table:
    • added columns TIME_MS, ROWS_EXAMINED, ROWS_SENT, and ROWS_READ

Version Specific Information

  • 5.5.10-20.1:
    • Added columns ROWS_EXAMINED, ROWS_SENT, and ROWS_READ to SHOW PROCESSLIST command.
    • Added columns ROWS_EXAMINED, ROWS_SENT, and ROWS_READ to PROCESSLIST table.

INFORMATION_SCHEMA Tables

table INFORMATION_SCHEMA.PROCESSLIST

This table implements modifications to the standard MySQL INFORMATION_SCHEMA table PROCESSLIST.

Columns:
  • ID – The connection identifier.
  • USER – The MySQL user who issued the statement.
  • HOST – The host name of the client issuing the statement.
  • DB – The default database, if one is selected, otherwise NULL.
  • COMMAND – The type of command the thread is executing.
  • TIME – The time in seconds that the thread has been in its current state.
  • STATE – An action, event, or state that indicates what the thread is doing.
  • INFO – The statement that the thread is executing, or NULL if it is not executing any statement.
  • TIME_MS – The time in milliseconds that the thread has been in its current state.
  • ROWS_EXAMINED – The number of rows examined by the statement being executed (NOTE: This column is not updated for each examined row so it does not necessarily show an up-to-date value while the statement is executing. It only shows a correct value after the statement has completed.).
  • ROWS_SENT – The number of rows sent by the statement being executed.
  • ROWS_READ – The number of rows read by the statement being executed.

Example Output

SHOW PROCESSLIST Command:

mysql> show processlist;
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+-----------+---------------+-----------+
| Id   | User      | Host      | db     | Command | Time | State      | Info                                         | ROWS_SENT | ROWS_EXAMINED | ROWS_READ |
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+-----------+---------------+-----------+
|    2 | root      | localhost | test   | Query   |    0 | NULL       | SHOW PROCESSLIST                             |         0 |             0 |         1 |
|   14 | root      | localhost | test   | Query   |    0 | User lock  | SELECT GET_LOCK(``t``,1000)                    |         0 |             0 |         1 |
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+-----------+---------------+-----------+

Table PROCESSLIST:

mysql> select * from information_schema.PROCESSLIST;
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+----------+---------------+-----------+-----------+
| ID   | USER      | HOST      | DB     | COMMAND | TIME | STATE      | INFO                                         | TIME_MS  | ROWS_EXAMINED | ROWS_SENT | ROWS_READ |
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+----------+---------------+-----------+-----------+
|   14 | root      | localhost | test   | Query   |    0 | User lock  | SELECT GET_LOCK(``t``,1000)                    |        1 |             0 |         0   |         1 |
|    2 | root      | localhost | test   | Query   |    0 | executing  | SELECT * from INFORMATION_SCHEMA.PROCESSLIST |        0 |             0 |         0 |         1 |
+------+-----------+-----------+--------+---------+------+------------+----------------------------------------------+----------+---------------+-----------+-----------+
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