PROCESSLIST

PROCESSLIST, just like SHOW PROCESSLIST, is used to view the requests that are being handled.

The PROCESSLIST table has additional columns not present in SHOW PROCESSLIST:

  • A DIGEST column to show the digest of the SQL statement.
  • A MEM column to show the memory used by the request that is being processed, in bytes.
  • A DISK column to show the disk usage in bytes.
  • A TxnStart column to show the start time of the transaction.
  • A RESOURCE_GROUP column to show the resource group name.
  1. USE information_schema;
  2. DESC processlist;
  1. +---------------------+---------------------+------+------+---------+-------+
  2. | Field               | Type                | Null | Key  | Default | Extra |
  3. +---------------------+---------------------+------+------+---------+-------+
  4. | ID                  | bigint(21) unsigned | NO   |      | 0       |       |
  5. | USER                | varchar(16)         | NO   |      |         |       |
  6. | HOST                | varchar(64)         | NO   |      |         |       |
  7. | DB                  | varchar(64)         | YES  |      | NULL    |       |
  8. | COMMAND             | varchar(16)         | NO   |      |         |       |
  9. | TIME                | int(7)              | NO   |      | 0       |       |
  10. | STATE               | varchar(7)          | YES  |      | NULL    |       |
  11. | INFO                | longtext            | YES  |      | NULL    |       |
  12. | DIGEST              | varchar(64)         | YES  |      |         |       |
  13. | MEM                 | bigint(21) unsigned | YES  |      | NULL    |       |
  14. | DISK                | bigint(21) unsigned | YES  |      | NULL    |       |
  15. | TxnStart            | varchar(64)         | NO   |      |         |       |
  16. | RESOURCE_GROUP      | varchar(32)         | NO   |      |         |       |
  17. +---------------------+---------------------+------+------+---------+-------+
  18. 13 rows in set (0.00 sec)
  1. SELECT * FROM processlist\G
  1. *************************** 1. row ***************************
  2.                  ID: 2300033189772525975
  3.                USER: root
  4.                HOST: 127.0.0.1:51289
  5.                  DB: NULL
  6.             COMMAND: Query
  7.                TIME: 0
  8.               STATE: autocommit
  9.                INFO: SELECT * FROM processlist
  10.              DIGEST: dbfaa16980ec628011029f0aaf0d160f4b040885240dfc567bf760d96d374f7e
  11.                 MEM: 0
  12.                DISK: 0
  13.            TxnStart:
  14.      RESOURCE_GROUP: rg1
  15. 1 row in set (0.00 sec)

Fields in the PROCESSLIST table are described as follows:

  • ID: The ID of the user connection.
  • USER: The name of the user who is executing PROCESS.
  • HOST: The address that the user is connecting to.
  • DB: The name of the currently connected default database.
  • COMMAND: The command type that PROCESS is executing.
  • TIME: The current execution duration of PROCESS, in seconds.
  • STATE: The current connection state.
  • INFO: The requested statement that is being processed.
  • DIGEST: The digest of the SQL statement.
  • MEM: The memory used by the request that is being processed, in bytes.
  • DISK: The disk usage in bytes.
  • TxnStart: The start time of the transaction.
  • RESOURCE_GROUP: The resource group name.

CLUSTER_PROCESSLIST

CLUSTER_PROCESSLIST is the cluster system table corresponding to PROCESSLIST. It is used to query the PROCESSLIST information of all TiDB nodes in the cluster. The table schema of CLUSTER_PROCESSLIST has one more column than PROCESSLIST, the INSTANCE column, which stores the address of the TiDB node this row of data is from.

  1. SELECT * FROM information_schema.cluster_processlist;
  1. +-----------------+-----+------+----------+------+---------+------+------------+------------------------------------------------------+-----+----------------------------------------+----------------+
  2. | INSTANCE        | ID  | USER | HOST     | DB   | COMMAND | TIME | STATE      | INFO                                                 | MEM | TxnStart                               | RESOURCE_GROUP | 
  3. +-----------------+-----+------+----------+------+---------+------+------------+------------------------------------------------------+-----+----------------------------------------+----------------+
  5. | 10.0.1.22:10080 | 150 | u1   | 10.0.1.1 | test | Query   | 0    | autocommit | select count(*) from usertable                       | 372 | 05-28 03:54:21.230(416976223923077223) | default        |
  6. | 10.0.1.22:10080 | 138 | root | 10.0.1.1 | test | Query   | 0    | autocommit | SELECT * FROM information_schema.cluster_processlist | 0   | 05-28 03:54:21.230(416976223923077220) | rg1            |
  7. | 10.0.1.22:10080 | 151 | u1   | 10.0.1.1 | test | Query   | 0    | autocommit | select count(*) from usertable                       | 372 | 05-28 03:54:21.230(416976223923077224) | rg2            |
  8. | 10.0.1.21:10080 | 15  | u2   | 10.0.1.1 | test | Query   | 0    | autocommit | select max(field0) from usertable                    | 496 | 05-28 03:54:21.230(416976223923077222) | default        |
  9. | 10.0.1.21:10080 | 14  | u2   | 10.0.1.1 | test | Query   | 0    | autocommit | select max(field0) from usertable                    | 496 | 05-28 03:54:21.230(416976223923077225) | default        |
  10. +-----------------+-----+------+----------+------+---------+------+------------+------------------------------------------------------+-----+----------------------------------------+----------------+