ADMIN

This statement is a TiDB extension syntax, used to view the status of TiDB and check the data of tables in TiDB.

To view the currently running DDL jobs, use ADMIN SHOW DDL:

ADMIN SHOW DDL;

To view all the results in the current DDL job queue (including tasks that are running and waiting to be run) and the last ten results in the completed DDL job queue, use ADMIN SHOW DDL JOBS:

ADMIN SHOW DDL JOBS [NUM] [WHERE where_condition];
  • NUM: to view the last NUM results in the completed DDL job queue. If not specified, NUM is by default 10.
  • WHERE: to add filter conditions.

To view the original SQL statements of the DDL job corresponding to job_id, use ADMIN SHOW DDL JOB QUERIES:

ADMIN SHOW DDL JOB QUERIES job_id [, job_id] ...;

To cancel the running DDL job corresponding to job_id, use ADMIN CANCEL DDL JOBS. Executing this statement returns the message that indicates whether the job has been cancelled.

ADMIN CANCEL DDL JOBS job_id [, job_id] ...;

To check the consistency of all the data and corresponding indexes in the tbl_name table, use ADMIN CHECK TABLE. If the consistency check is passed, an empty result is returned. Otherwise, an error message is returned indicating that the data is inconsistent.

ADMIN CHECK TABLE tbl_name [, tbl_name] ...;

To overwrite the metadata of the stored table in an untrusted way in extreme cases, use ADMIN REPAIR TABLE. Here “untrusted” means that you need to manually ensure that the metadata of the original table can be covered by the CREATE TABLE STATEMENT operation. To use this REPAIR statement, enable the repair-mode configuration item, and make sure that the tables to be repaired are listed in the repair-table-list.

ADMIN REPAIR TABLE tbl_name CREATE TABLE STATEMENT;

Synopsis

AdminStmt:

AdminStmt

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 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. For details, see the paper Online, Asynchronous Schema Change in F1. 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.
  • ADMIN SHOW DDL JOB QUERIES job_id [, job_id] ...: To view the original SQL statement of the DDL job corresponding to the job_id; the job_id only searches the running DDL job and the last ten results in the DDL history job queue

  • ADMIN CANCEL DDL JOBS job_id [, job_id] ...: To cancel the currently running DDL jobs and return whether the corresponding jobs are successfully cancelled. If the operation fails to cancel the jobs, specific reasons are displayed.

    Note:

    • Only this operation can cancel DDL jobs. All other operations and environment changes (such as machine restart and cluster restart) cannot cancel these jobs.
    • This operation can cancel multiple DDL jobs at the same time. You can get the ID of DDL jobs using the ADMIN SHOW DDL JOBS statement.
    • If the jobs you want to cancel are finished, the cancellation operation fails.
  • ADMIN CHECK TABLE tbl_name [, tbl_name] ...: To check the consistency of all the data in the specified table and corresponding indexes. If the check is passed, an empty result is returned. Otherwise, an error message is returned indicating that the data is inconsistent.

  • ADMIN REPAIR TABLE tbl_name CREATE TABLE STATEMENT: In extreme cases, this statement is used to overwrite the metadata of the stored table in an untrusted way. Here “untrusted” means that you need to manually ensure that the metadata of the original table can be covered by the CREATE TABLE STATEMENT operation. To use this REPAIR statement, enable the repair-mode configuration item, and make sure that the tables to be repaired are listed in the repair-table-list.

MySQL compatibility

This statement is a TiDB extension to MySQL syntax.