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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. The returned result fields are described as follows:

  • 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\G;

*************************** 1. row ***************************
   SCHEMA_VER: 26
     OWNER_ID: 2d1982af-fa63-43ad-a3d5-73710683cc63
OWNER_ADDRESS: 0.0.0.0:4000
 RUNNING_JOBS:
      SELF_ID: 2d1982af-fa63-43ad-a3d5-73710683cc63
        QUERY:
1 row in set (0.00 sec)

ADMIN SHOW DDL JOBS

The ADMIN SHOW DDL JOBS statement is used to view the 10 jobs in the current DDL job queue, including running and pending jobs (if any), and the last 10 jobs in the executed DDL job queue (if any). 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:
  • 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.
  • CREATE_TIME: the creation time of the DDL operation.
  • START_TIME: the start time of the DDL operation.
  • END_TIME: the end time of the DDL operation.
  • STATE: the state of the DDL operation. Common states include the following:
    • none: indicates that the operation has not started yet.
    • 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, the queueing state will become the done 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.
    • cancelled: indicates that the operation has been canceled.
    • pausing: indicates that the operation is being paused.
    • paused: 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.
    • done: indicates that the operation has been successfully executed on the TiDB owner node, but other TiDB nodes have not yet synchronized the changes performed by this DDL job.
  • COMMENTS: contains additional information for diagnostic purposes.
    • ingest: ingest tasks for accelerated adding index backfill configured via tidb_ddl_enable_fast_reorg。
    • txn: transaction-based index backfill after tidb_ddl_enable_fast_reorg is disabled.
    • txn-merge: transactional backfilling with a temporary index that gets merged with the original index when the backfilling is finished.
    • DXF: tasks executed with Distributed eXecution Framework (DXF) configured via tidb_enable_dist_task.
    • service_scope: the service scope of the TiDB node configured via tidb_service_scope.
    • thread: the concurrency of backfill tasks. You can set the initial value by tidb_ddl_reorg_worker_cnt. It supports dynamic modification via ADMIN ALTER DDL JOBS.
    • batch_size: the batch size of backfill tasks. You can set the initial value by tidb_ddl_reorg_batch_size. It supports dynamic modification via ADMIN ALTER DDL JOBS.
    • max_write_speed: flow control during ingest task import. The initial value can be set with tidb_ddl_reorg_max_write_speed. It supports dynamic modification via ADMIN ALTER DDL JOBS.

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

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    | COMMENTS    |
+--------+---------+------------+---------------------------------+----------------------+-----------+----------+-----------+----------------------------+----------------------------+----------------------------+----------+-------------+
|    565 | test    | sbtest1    | add index                       | write reorganization |       554 |      556 |         0 | 2024-11-22 12:39:25.475000 | 2024-11-22 12:39:25.524000 | NULL                       | running  | ingest, DXF |
|    566 | test    | sbtest1    | add index                       | none                 |       554 |      556 |         0 | 2024-11-22 12:39:26.425000 | NULL                       | NULL                       | queueing |             |
|    564 | test    | sbtest1    | alter table multi-schema change | none                 |       554 |      556 |         0 | 2024-11-22 12:39:02.925000 | 2024-11-22 12:39:02.925000 | 2024-11-22 12:39:03.275000 | synced   |             |
|    564 | test    | sbtest1    | drop index /* subjob */         | none                 |       554 |      556 |         0 | 2024-11-22 12:39:02.925000 | 2024-11-22 12:39:02.925000 | 2024-11-22 12:39:03.275000 | done     |             |
|    564 | test    | sbtest1    | drop index /* subjob */         | none                 |       554 |      556 |         0 | 2024-11-22 12:39:02.925000 | 2024-11-22 12:39:02.975000 | 2024-11-22 12:39:03.275000 | done     |             |
|    563 | test    | sbtest1    | modify column                   | public               |       554 |      556 |         0 | 2024-11-22 12:38:35.624000 | 2024-11-22 12:38:35.624000 | 2024-11-22 12:38:35.674000 | synced   |             |
|    562 | test    | sbtest1    | add index                       | public               |       554 |      556 |   1580334 | 2024-11-22 12:36:58.471000 | 2024-11-22 12:37:05.271000 | 2024-11-22 12:37:13.374000 | synced   | ingest, DXF |
|    561 | test    | sbtest1    | add index                       | public               |       554 |      556 |   1580334 | 2024-11-22 12:36:57.771000 | 2024-11-22 12:36:57.771000 | 2024-11-22 12:37:04.671000 | synced   | ingest, DXF |
|    560 | test    | sbtest1    | add index                       | public               |       554 |      556 |   1580334 | 2024-11-22 12:34:53.314000 | 2024-11-22 12:34:53.314000 | 2024-11-22 12:34:57.114000 | synced   | ingest      |
|    559 | test    | sbtest1    | drop index                      | none                 |       554 |      556 |         0 | 2024-11-22 12:34:43.565000 | 2024-11-22 12:34:43.565000 | 2024-11-22 12:34:43.764000 | synced   |             |
|    558 | test    | sbtest1    | add index                       | public               |       554 |      556 |   1580334 | 2024-11-22 12:34:06.215000 | 2024-11-22 12:34:06.215000 | 2024-11-22 12:34:14.314000 | synced   | ingest, DXF |
|    557 | test    | sbtest1    | create table                    | public               |       554 |      556 |         0 | 2024-11-22 12:32:09.515000 | 2024-11-22 12:32:09.915000 | 2024-11-22 12:32:10.015000 | synced   |             |
|    555 | test    |            | create schema                   | public               |       554 |        0 |         0 | 2024-11-22 12:31:51.215000 | 2024-11-22 12:31:51.264000 | 2024-11-22 12:31:51.264000 | synced   |             |
|    553 | test    |            | drop schema                     | none                 |         2 |        0 |         0 | 2024-11-22 12:31:48.615000 | 2024-11-22 12:31:48.615000 | 2024-11-22 12:31:48.865000 | synced   |             |
+--------+---------+------------+---------------------------------+----------------------+-----------+----------+-----------+----------------------------+----------------------------+----------------------------+----------+-------------+
14 rows in set (0.00 sec)

From the output above:

  • Job 565 is currently in progress (STATE of running). The schema state is currently in write reorganization, but will switch to public once the job 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.

  • The STATE for job_id 566 is shown as queueing, indicating that it is queuing. When job 565 completes and job 566 begins execution, the STATE for job 566 will change 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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