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information-schema-processlist.md

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PROCESSLIST
Learn the `PROCESSLIST` information_schema table.

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.
  • A SESSION_ALIAS column to show the alias of the current session.
  • A ROWS_AFFECTED column to show the number of rows currently affected by the statement.
  • A TIDB_CPU column to show the amount of time in nanoseconds that the statement consumes the TiDB server CPU. This column shows meaningful value only when the Top SQL feature is enabled. Otherwise the value will be 0.
  • A TIKV_CPU column to show the amount of time in nanoseconds that the statement consumes the TiKV server CPU.
  • 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.
  • A SESSION_ALIAS column to show the alias of the current session.
  • A ROWS_AFFECTED column to show the number of rows currently affected by the statement.
  • A TIDB_CPU column to show the amount of time in nanoseconds that the statement consumes the TiDB server CPU. This column shows meaningful value only when the Top SQL feature is enabled. Otherwise the value will be 0.
  • A TIKV_CPU column to show the amount of time in nanoseconds that the statement consumes the TiKV server CPU.
USE information_schema;
DESC processlist;
+----------------+---------------------+------+------+---------+-------+
| Field          | Type                | Null | Key  | Default | Extra |
+----------------+---------------------+------+------+---------+-------+
| ID             | bigint(21) unsigned | NO   |      | 0       |       |
| USER           | varchar(16)         | NO   |      |         |       |
| HOST           | varchar(64)         | NO   |      |         |       |
| DB             | varchar(64)         | YES  |      | NULL    |       |
| COMMAND        | varchar(16)         | NO   |      |         |       |
| TIME           | int(7)              | NO   |      | 0       |       |
| STATE          | varchar(7)          | YES  |      | NULL    |       |
| INFO           | longtext            | YES  |      | NULL    |       |
| DIGEST         | varchar(64)         | YES  |      |         |       |
| MEM            | bigint(21) unsigned | YES  |      | NULL    |       |
| DISK           | bigint(21) unsigned | YES  |      | NULL    |       |
| TxnStart       | varchar(64)         | NO   |      |         |       |
| RESOURCE_GROUP | varchar(32)         | NO   |      |         |       |
| SESSION_ALIAS  | varchar(64)         | NO   |      |         |       |
| ROWS_AFFECTED  | bigint(21) unsigned | YES  |      | NULL    |       |
| TIDB_CPU       | bigint(21)          | NO   |      | 0       |       |
| TIKV_CPU       | bigint(21)          | NO   |      | 0       |       |
+----------------+---------------------+------+------+---------+-------+
SELECT * FROM information_schema.processlist\G
*************************** 1. row ***************************
            ID: 1268776964
          USER: root
          HOST: 127.0.0.1:59922
            DB: NULL
       COMMAND: Query
          TIME: 0
         STATE: autocommit
          INFO: SELECT * FROM information_schema.processlist
        DIGEST: 4b5e7cdd5d3ed84d6c1a6d56403a3d512554b534313caf296268abdec1c9ea99
           MEM: 0
          DISK: 0
      TxnStart:
RESOURCE_GROUP: default
 SESSION_ALIAS:
 ROWS_AFFECTED: 0
      TIDB_CPU: 0
      TIKV_CPU: 0

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.
  • SESSION_ALIAS: The alias of the current session.
  • ROWS_AFFECTED: The number of rows currently affected by the statement.
  • TIDB_CPU: The amount of time in nanoseconds that the statement consumes the TiDB server CPU. This column shows meaningful value only when the Top SQL feature is enabled. Otherwise the value will be 0.
  • TIKV_CPU: The amount of time in nanoseconds that the statement consumes the TiKV server CPU.
  • 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.
  • SESSION_ALIAS: The alias of the current session.
  • ROWS_AFFECTED: The number of rows currently affected by the statement.
  • TIDB_CPU: The amount of time in nanoseconds that the statement consumes the TiDB server CPU. This column shows meaningful value only when the Top SQL feature is enabled. Otherwise the value will be 0.
  • TIKV_CPU: The amount of time in nanoseconds that the statement consumes the TiKV server CPU.

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.

SELECT * FROM information_schema.cluster_processlist;
+-----------------+------------+------+-----------------+------+---------+------+------------+------------------------------------------------------+------------------------------------------------------------------+------+------+----------------------------------------+----------------+---------------+---------------+----------+----------+
| INSTANCE        | ID         | USER | HOST            | DB   | COMMAND | TIME | STATE      | INFO                                                 | DIGEST                                                           | MEM  | DISK | TxnStart                               | RESOURCE_GROUP | SESSION_ALIAS | ROWS_AFFECTED | TIDB_CPU | TIKV_CPU |
+-----------------+------------+------+-----------------+------+---------+------+------------+------------------------------------------------------+------------------------------------------------------------------+------+------+----------------------------------------+----------------+---------------+---------------+----------+----------+
| 127.0.0.1:10080 | 1268776964 | root | 127.0.0.1:59922 | NULL | Query   |    0 | autocommit | SELECT * FROM information_schema.cluster_processlist | b1e38e59fbbc3e2b35546db5c8053040db989a497ac6cd71ff8dd4394395701a |    0 |    0 | 07-29 12:39:24.282(451471727468740609) | default        |               |             0 |        0 |        0 |
+-----------------+------------+------+-----------------+------+---------+------+------------+------------------------------------------------------+------------------------------------------------------------------+------+------+----------------------------------------+----------------+---------------+---------------+----------+----------+