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ADMIN SHOW DDL [JOBS|JOB QUERIES]

The ADMIN SHOW DDL [JOBS|JOB QUERIES] statement shows information about running and recently completed DDL jobs.

Synopsis

AdminShowDDLStmt
ADMINSHOWDDLJOBSInt64NumWhereClauseOptionalJOBQUERIESNumListJOBQUERIESLIMITmOFFSET,n
NumList
Int64Num,
WhereClauseOptional
WhereClause

Examples

ADMIN SHOW DDL

To view the status of the currently running DDL jobs, use ADMIN SHOW DDL. The output includes the current schema version, the DDL ID and address of the owner, the running DDL jobs and SQL statements, and the DDL ID of the current TiDB instance.

  • SCHEMA_VER: a number indicating the version of the schema.
  • OWNER_ID: the UUID of the DDL owner. See also TIDB_IS_DDL_OWNER().
  • OWNER_ADDRESS: the IP address of the DDL owner.
  • RUNNING_JOBS: details about the running DDL job.
  • SELF_ID: the UUID of the TiDB node to which you are currently connected. If SELF_ID is the same as the OWNER_ID, it means that you are connected to the DDL owner.
  • QUERY: the statements of the queries.
ADMIN SHOW DDL;

mysql> ADMIN SHOW DDL;
+------------+--------------------------------------+---------------+--------------+--------------------------------------+-------+
| SCHEMA_VER | OWNER_ID                             | OWNER_ADDRESS | RUNNING_JOBS | SELF_ID                              | QUERY |
+------------+--------------------------------------+---------------+--------------+--------------------------------------+-------+
|         26 | 2d1982af-fa63-43ad-a3d5-73710683cc63 | 0.0.0.0:4000  |              | 2d1982af-fa63-43ad-a3d5-73710683cc63 |       |
+------------+--------------------------------------+---------------+--------------+--------------------------------------+-------+
1 row in set (0.00 sec)

ADMIN SHOW DDL JOBS

The ADMIN SHOW DDL JOBS statement is used to view all the results in the current DDL job queue, including running and queuing tasks, as well as the latest ten results in the completed DDL job queue. The returned result fields are described as follows:

  • JOB_ID: each DDL operation corresponds to a DDL job. JOB_ID is globally unique.
  • DB_NAME: the name of the database where the DDL operation is performed.
  • TABLE_NAME: the name of the table where the DDL operation is performed.
  • JOB_TYPE: the type of DDL operation. Common job types include the following:
    • ingest: Ingestion with accelerated index backfilling as configured by tidb_ddl_enable_fast_reorg.
    • txn: Basic transactional backfill.
    • txn-merge: Transactional backfill with a temporary index that gets merged with the original index when the backfill is finished.
  • SCHEMA_STATE: the current state of the schema object that the DDL operates on. If JOB_TYPE is ADD INDEX, it is the state of the index; if JOB_TYPE is ADD COLUMN, it is the state of the column; if JOB_TYPE is CREATE TABLE, it is the state of the table. Common states include the following:
    • none: indicates that it does not exist. Generally, after the DROP operation or after the CREATE operation fails and rolls back, it will become the none state.
    • delete only, write only, delete reorganization, write reorganization: these four states are intermediate states. For their specific meanings, see How the Online DDL Asynchronous Change Works in TiDB. As the intermediate state conversion is fast, these states are generally not visible during operation. Only when performing ADD INDEX operation can the write reorganization state be seen, indicating that index data is being added.
    • public: indicates that it exists and is available to users. Generally, after CREATE TABLE and ADD INDEX (or ADD COLUMN) operations are completed, it will become the public state, indicating that the newly created table, column, and index can be read and written normally.
  • SCHEMA_ID: the ID of the database where the DDL operation is performed.
  • TABLE_ID: the ID of the table where the DDL operation is performed.
  • ROW_COUNT: when performing the ADD INDEX operation, it is the number of data rows that have been added.
  • START_TIME: the start time of the DDL operation.
  • STATE: the state of the DDL operation. Common states include the following:
    • queueing: indicates that the operation job has entered the DDL job queue but has not been executed because it is still waiting for an earlier DDL job to complete. Another reason might be that after executing the DROP operation, it will become the none state, but it will soon be updated to the synced state, indicating that all TiDB instances have been synchronized to that state.
    • running: indicates that the operation is being executed.
    • synced: indicates that the operation has been executed successfully and all TiDB instances have been synchronized to this state.
    • rollback done: indicates that the operation has failed and the rollback has been completed.
    • rollingback: indicates that the operation has failed and is rolling back.
    • cancelling: indicates that the operation is being canceled. This state only appears when you use the ADMIN CANCEL DDL JOBS command to cancel the DDL job.

The following example shows the results of ADMIN SHOW DDL JOBS:

ADMIN SHOW DDL JOBS;

mysql> ADMIN SHOW DDL JOBS;
+--------+---------+--------------------+--------------+----------------------+-----------+----------+-----------+-----------------------------------------------------------------+---------+
| JOB_ID | DB_NAME | TABLE_NAME         | JOB_TYPE     | SCHEMA_STATE         | SCHEMA_ID | TABLE_ID | ROW_COUNT | CREATE_TIME         | START_TIME          | END_TIME            | STATE   |
+--------+---------+--------------------+--------------+----------------------+-----------+----------+-----------+---------------------+-------------------------------------------+---------+
|     59 | test    | t1                 | add index    | write reorganization |         1 |       55 |     88576 | 2020-08-17 07:51:58 | 2020-08-17 07:51:58 | NULL                | running |
|     60 | test    | t2                 | add index    | none                 |         1 |       57 |         0 | 2020-08-17 07:51:59 | 2020-08-17 07:51:59 | NULL                | none    |
|     58 | test    | t2                 | create table | public               |         1 |       57 |         0 | 2020-08-17 07:41:28 | 2020-08-17 07:41:28 | 2020-08-17 07:41:28 | synced  |
|     56 | test    | t1                 | create table | public               |         1 |       55 |         0 | 2020-08-17 07:41:02 | 2020-08-17 07:41:02 | 2020-08-17 07:41:02 | synced  |
|     54 | test    | t1                 | drop table   | none                 |         1 |       50 |         0 | 2020-08-17 07:41:02 | 2020-08-17 07:41:02 | 2020-08-17 07:41:02 | synced  |
|     53 | test    | t1                 | drop index   | none                 |         1 |       50 |         0 | 2020-08-17 07:35:44 | 2020-08-17 07:35:44 | 2020-08-17 07:35:44 | synced  |
|     52 | test    | t1                 | add index    | public               |         1 |       50 |    451010 | 2020-08-17 07:34:43 | 2020-08-17 07:34:43 | 2020-08-17 07:35:16 | synced  |
|     51 | test    | t1                 | create table | public               |         1 |       50 |         0 | 2020-08-17 07:34:02 | 2020-08-17 07:34:02 | 2020-08-17 07:34:02 | synced  |
|     49 | test    | t1                 | drop table   | none                 |         1 |       47 |         0 | 2020-08-17 07:34:02 | 2020-08-17 07:34:02 | 2020-08-17 07:34:02 | synced  |
|     48 | test    | t1                 | create table | public               |         1 |       47 |         0 | 2020-08-17 07:33:37 | 2020-08-17 07:33:37 | 2020-08-17 07:33:37 | synced  |
|     46 | mysql   | stats_extended     | create table | public               |         3 |       45 |         0 | 2020-08-17 06:42:38 | 2020-08-17 06:42:38 | 2020-08-17 06:42:38 | synced  |
|     44 | mysql   | opt_rule_blacklist | create table | public               |         3 |       43 |         0 | 2020-08-17 06:42:38 | 2020-08-17 06:42:38 | 2020-08-17 06:42:38 | synced  |
+--------+---------+--------------------+--------------+----------------------+-----------+----------+-----------+---------------------+---------------------+-------------------------------+
12 rows in set (0.00 sec)

From the output above:

  • Job 59 is currently in progress (STATE of running). The schema state is currently in write reorganization, but will switch to public once the task is completed to note that the change can be observed publicly by user sessions. The end_time column is also NULL indicating that the completion time for the job is currently not known.

  • Job 60 is an add index job, which is currently queued waiting for job 59 to complete. When job 59 completes, the STATE of job 60 will switch to running.

  • For destructive changes such as dropping an index or dropping a table, the SCHEMA_STATE will change to none when the job is complete. For additive changes, the SCHEMA_STATE will change to public.

To limit the number of rows shown, specify a number and a where condition:

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.

ADMIN SHOW DDL JOB QUERIES

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

ADMIN SHOW DDL JOBS;
ADMIN SHOW DDL JOB QUERIES 51;

mysql> ADMIN SHOW DDL JOB QUERIES 51;
+--------------------------------------------------------------+
| QUERY                                                        |
+--------------------------------------------------------------+
| CREATE TABLE t1 (id INT NOT NULL PRIMARY KEY auto_increment) |
+--------------------------------------------------------------+
1 row in set (0.02 sec)

You can only search the running DDL job corresponding to job_id within the last ten results in the DDL history job queue.

ADMIN SHOW DDL JOB QUERIES LIMIT m OFFSET n

To view the original SQL statements of the DDL job within a specified range [n+1, n+m] corresponding to job_id, use ADMIN SHOW DDL JOB QUERIES LIMIT m OFFSET n:

 ADMIN SHOW DDL JOB QUERIES LIMIT m;  # Retrieve first m rows
 ADMIN SHOW DDL JOB QUERIES LIMIT n, m;  # Retrieve rows [n+1, n+m]
 ADMIN SHOW DDL JOB QUERIES LIMIT m OFFSET n;  # Retrieve rows [n+1, n+m]

where n and m are integers greater or equal to 0.

ADMIN SHOW DDL JOB QUERIES LIMIT 3;  # Retrieve first 3 rows
+--------+--------------------------------------------------------------+
| JOB_ID | QUERY                                                        |
+--------+--------------------------------------------------------------+
|     59 | ALTER TABLE t1 ADD INDEX index2 (col2)                       |
|     60 | ALTER TABLE t2 ADD INDEX index1 (col1)                       |
|     58 | CREATE TABLE t2 (id INT NOT NULL PRIMARY KEY auto_increment) |
+--------+--------------------------------------------------------------+
3 rows in set (0.00 sec)

ADMIN SHOW DDL JOB QUERIES LIMIT 6, 2;  # Retrieve rows 7-8
+--------+----------------------------------------------------------------------------+
| JOB_ID | QUERY                                                                      |
+--------+----------------------------------------------------------------------------+
|     52 | ALTER TABLE t1 ADD INDEX index1 (col1)                                     |
|     51 | CREATE TABLE IF NOT EXISTS t1 (id INT NOT NULL PRIMARY KEY auto_increment) |
+--------+----------------------------------------------------------------------------+
3 rows in set (0.00 sec)

ADMIN SHOW DDL JOB QUERIES LIMIT 3 OFFSET 4;  # Retrieve rows 5-7
+--------+----------------------------------------+
| JOB_ID | QUERY                                  |
+--------+----------------------------------------+
|     54 | DROP TABLE IF EXISTS t3                |
|     53 | ALTER TABLE t1 DROP INDEX index1       |
|     52 | ALTER TABLE t1 ADD INDEX index1 (col1) |
+--------+----------------------------------------+
3 rows in set (0.00 sec)

You can search the running DDL job corresponding to job_id within an arbitrarily specified range of results in the DDL history job queue. This syntax does not have the limitation of the last ten results of ADMIN SHOW DDL JOB QUERIES.

MySQL compatibility

This statement is a TiDB extension to MySQL syntax.

See also

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