ADMIN

This statement is a TiDB extension syntax, used to view the status of TiDB and check the data of tables in TiDB. This document introduces the following ADMIN related statements:

• ADMIN RELOAD
• ADMIN PLUGINS
• ADMIN ... BINDINGS
• ADMIN REPAIR
• ADMIN SHOW NEXT_ROW_ID
• ADMIN SHOW SLOW

DDL related statement

ADMIN RELOAD statement

ADMIN RELOAD expr_pushdown_blacklist;

The above statement is used to reload the blocklist pushed down by the expression.

ADMIN RELOAD opt_rule_blacklist;

The above statement is used to reload the blocklist of logic optimization rules.

ADMIN PLUGINS related statement

ADMIN PLUGINS ENABLE plugin_name [, plugin_name] ...;

The above statement is used to enable the plugin_name plugin.

ADMIN PLUGINS DISABLE plugin_name [, plugin_name] ...;

The above statement is used to disable the plugin_name plugin.

ADMIN BINDINGS related statement

ADMIN FLUSH BINDINGS;

The above statement is used to persist SQL Plan binding information.

ADMIN CAPTURE BINDINGS;

The above statement can generate the binding of SQL Plan from the SELECT statement that occurs more than once.

ADMIN EVOLVE BINDINGS;

After the automatic binding feature is enabled, the evolution of SQL Plan binding information is triggered every bind-info-leave (the default value is 3s). The above statement is used to proactively trigger this evolution.

ADMIN RELOAD BINDINGS;

The above statement is used to reload SQL Plan binding information.

ADMIN REPAIR statement

To overwrite the metadata of the stored table in an untrusted way in extreme cases, use ADMIN REPAIR TABLE:

ADMIN REPAIR TABLE tbl_name CREATE TABLE STATEMENT;

ADMIN SHOW NEXT_ROW_ID statement

ADMIN SHOW t NEXT_ROW_ID;

The above statement is used to view the details of some special columns of a table. The output is the same as SHOW TABLE NEXT_ROW_ID.

ADMIN SHOW SLOW statement

ADMIN SHOW SLOW RECENT N;

ADMIN SHOW SLOW TOP [INTERNAL | ALL] N;

Synopsis

AdminStmt ::=
    'ADMIN' ( 'SHOW' ( 'DDL' ( 'JOBS' Int64Num? WhereClauseOptional | 'JOB' 'QUERIES' NumList )? | TableName 'NEXT_ROW_ID' | 'SLOW' AdminShowSlow ) | 'CHECK' ( 'TABLE' TableNameList | 'INDEX' TableName Identifier ( HandleRange ( ',' HandleRange )* )? ) | 'RECOVER' 'INDEX' TableName Identifier | 'CLEANUP' ( 'INDEX' TableName Identifier | 'TABLE' 'LOCK' TableNameList ) | 'CHECKSUM' 'TABLE' TableNameList | 'CANCEL' 'DDL' 'JOBS' NumList | 'RELOAD' ( 'EXPR_PUSHDOWN_BLACKLIST' | 'OPT_RULE_BLACKLIST' | 'BINDINGS' ) | 'PLUGINS' ( 'ENABLE' | 'DISABLE' ) PluginNameList | 'REPAIR' 'TABLE' TableName CreateTableStmt | ( 'FLUSH' | 'CAPTURE' | 'EVOLVE' ) 'BINDINGS' )

Examples

Run the following command to view the last 10 completed DDL jobs in the currently running DDL job queue. When NUM is not specified, only the last 10 completed DDL jobs is presented by default.

ADMIN SHOW DDL JOBS;

+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| JOB_ID | DB_NAME | TABLE_NAME | JOB_TYPE            | SCHEMA_STATE   | SCHEMA_ID | TABLE_ID | ROW_COUNT | START_TIME                        | END_TIME                          | STATE         |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| 45     | test    | t1         | add index     | write reorganization | 32        | 37       | 0         | 2019-01-10 12:38:36.501 +0800 CST |                                   | running       |
| 44     | test    | t1         | add index     | none                 | 32        | 37       | 0         | 2019-01-10 12:36:55.18 +0800 CST  | 2019-01-10 12:36:55.852 +0800 CST | rollback done |
| 43     | test    | t1         | add index     | public               | 32        | 37       | 6         | 2019-01-10 12:35:13.66 +0800 CST  | 2019-01-10 12:35:14.925 +0800 CST | synced        |
| 42     | test    | t1         | drop index    | none                 | 32        | 37       | 0         | 2019-01-10 12:34:35.204 +0800 CST | 2019-01-10 12:34:36.958 +0800 CST | synced        |
| 41     | test    | t1         | add index     | public               | 32        | 37       | 0         | 2019-01-10 12:33:22.62 +0800 CST  | 2019-01-10 12:33:24.625 +0800 CST | synced        |
| 40     | test    | t1         | drop column   | none                 | 32        | 37       | 0         | 2019-01-10 12:33:08.212 +0800 CST | 2019-01-10 12:33:09.78 +0800 CST  | synced        |
| 39     | test    | t1         | add column    | public               | 32        | 37       | 0         | 2019-01-10 12:32:55.42 +0800 CST  | 2019-01-10 12:32:56.24 +0800 CST  | synced        |
| 38     | test    | t1         | create table  | public               | 32        | 37       | 0         | 2019-01-10 12:32:41.956 +0800 CST | 2019-01-10 12:32:43.956 +0800 CST | synced        |
| 36     | test    |            | drop table    | none                 | 32        | 34       | 0         | 2019-01-10 11:29:59.982 +0800 CST | 2019-01-10 11:30:00.45 +0800  CST | synced        |
| 35     | test    |            | create table  | public               | 32        | 34       | 0         | 2019-01-10 11:29:40.741 +0800 CST | 2019-01-10 11:29:41.682 +0800 CST | synced        |
| 33     | test    |            | create schema | public               | 32        | 0        | 0         | 2019-01-10 11:29:22.813 +0800 CST | 2019-01-10 11:29:23.954 +0800 CST | synced        |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+

Run the following command to view the last 5 completed DDL jobs in the currently running DDL job queue:

ADMIN SHOW DDL JOBS 5;

+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| JOB_ID | DB_NAME | TABLE_NAME | JOB_TYPE            | SCHEMA_STATE   | SCHEMA_ID | TABLE_ID | ROW_COUNT | START_TIME                        | END_TIME                          | STATE         |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| 45     | test    | t1         | add index     | write reorganization | 32        | 37       | 0         | 2019-01-10 12:38:36.501 +0800 CST |                                   | running       |
| 44     | test    | t1         | add index     | none                 | 32        | 37       | 0         | 2019-01-10 12:36:55.18 +0800 CST  | 2019-01-10 12:36:55.852 +0800 CST | rollback done |
| 43     | test    | t1         | add index     | public               | 32        | 37       | 6         | 2019-01-10 12:35:13.66 +0800 CST  | 2019-01-10 12:35:14.925 +0800 CST | synced        |
| 42     | test    | t1         | drop index    | none                 | 32        | 37       | 0         | 2019-01-10 12:34:35.204 +0800 CST | 2019-01-10 12:34:36.958 +0800 CST | synced        |
| 41     | test    | t1         | add index     | public               | 32        | 37       | 0         | 2019-01-10 12:33:22.62 +0800 CST  | 2019-01-10 12:33:24.625 +0800 CST | synced        |
| 40     | test    | t1         | drop column   | none                 | 32        | 37       | 0         | 2019-01-10 12:33:08.212 +0800 CST | 2019-01-10 12:33:09.78 +0800 CST  | synced        |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+

Run the following command to view the details of some special columns of a table. The output is the same as SHOW TABLE NEXT_ROW_ID.

ADMIN SHOW t NEXT_ROW_ID;

+---------+------------+-------------+--------------------+----------------+
| DB_NAME | TABLE_NAME | COLUMN_NAME | NEXT_GLOBAL_ROW_ID | ID_TYPE        |
+---------+------------+-------------+--------------------+----------------+
| test    | t          | _tidb_rowid |                101 | _TIDB_ROWID    |
| test    | t          | _tidb_rowid |                  1 | AUTO_INCREMENT |
+---------+------------+-------------+--------------------+----------------+
2 rows in set (0.01 sec)

Run the following command to view the uncompleted DDL jobs in the test database. The results include the DDL jobs that are running and the last 5 DDL jobs that are completed but failed.

ADMIN SHOW DDL JOBS 5 WHERE state != 'synced' AND db_name = 'test';

+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| JOB_ID | DB_NAME | TABLE_NAME | JOB_TYPE            | SCHEMA_STATE   | SCHEMA_ID | TABLE_ID | ROW_COUNT | START_TIME                        | END_TIME                          | STATE         |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+
| 45     | test    | t1         | add index     | write reorganization | 32        | 37       | 0         | 2019-01-10 12:38:36.501 +0800 CST |                                   | running       |
| 44     | test    | t1         | add index     | none                 | 32        | 37       | 0         | 2019-01-10 12:36:55.18 +0800 CST  | 2019-01-10 12:36:55.852 +0800 CST | rollback done |
+--------+---------+------------+---------------------+----------------+-----------+----------+-----------+-----------------------------------+-----------------------------------+---------------+

• JOB_ID: each DDL operation corresponds to one DDL job. JOB_ID is globally unique.
• DB_NAME: the name of the database on which the DDL operations are performed.
• TABLE_NAME: the name of the table on which the DDL operations are performed.
• JOB_TYPE: the type of the DDL operations.
• SCHEMA_STATE: the current state of the schema. If the JOB_TYPE is add index, it is the state of the index; if the JOB_TYPE is add column, it is the state of the column; if the JOB_TYPE is create table, it is the state of the table. The common states include:
  • none: it indicates not existing. When the drop or create operation fails and rolls back, it usually becomes the none state.
  • delete only, write only, delete reorganization, write reorganization: these four states are intermediate states. These states are not visible in common operations, because the conversion from the intermediate states is so quick. You can see the write reorganization state only in add index operations, which means that the index data is being added.
  • public: it indicates existing and usable. When operations like create table and add index/column are finished, it usually becomes the public state, which means that the created table/column/index can be normally read and written now.
• SCHEMA_ID: the ID of the database on which the DDL operations are performed.
• TABLE_ID: the ID of the table on which the DDL operations are performed.
• ROW_COUNT: the number of the data rows that have been added when running the add index operation.
• START_TIME: the start time of the DDL operations.
• END_TIME: the end time of the DDL operations.
• STATE: the state of the DDL operations. The common states include:
  • none: it indicates that the operation task has been put in the DDL job queue but has not been performed yet, because it is waiting for the previous tasks to complete. Another reason might be that it becomes the none state after running the drop operation, but it will soon be updated to the synced state, which means that all TiDB instances have been synced to this state.
  • running: it indicates that the operation is being performed.
  • synced: it indicates that the operation has been performed successfully and all TiDB instances have been synced to this state.
  • rollback done: it indicates that the operation has failed and has finished rolling back.
  • rollingback: it indicates that the operation has failed and is rolling back.
  • cancelling: it indicates that the operation is being cancelled. This state only occurs when you cancel DDL jobs using the ADMIN CANCEL DDL JOBS command.
  • paused: it indicates that the operation has been paused. This state only appears when you use the ADMIN PAUSED DDL JOBS command to pause the DDL job. You can use the ADMIN RESUME DDL JOBS command to resume the DDL job.

MySQL compatibility

This statement is a TiDB extension to MySQL syntax.