SHOW ALTER

Description

This statement is used to display the execution status of various ongoing modification tasks.

SHOW ALTER [TABLE [COLUMN | ROLLUP] [FROM db_name]];

Notes:

1. TABLE COLUMN: Displays ALTER tasks for modifying columns.
2. Supported syntax: [WHERE TableName|CreateTime|FinishTime|State] [ORDER BY] [LIMIT].
3. TABLE ROLLUP: Displays tasks for creating or deleting ROLLUP.
4. If db_name is not specified, the current default database is used.

Result

SHOW ALTER TABLE COLUMN

Field Name	Description
JobId	Unique ID for each Schema Change job.
TableName	The name of the base table corresponding to the Schema Change.
CreateTime	Job creation time.
FinishedTime	Job completion time. If not completed, shows "N/A".
IndexName	The name of a base table/synchronized materialized view involved in this modification.
IndexId	ID of the new base table/synchronized materialized view.
OriginIndexId	ID of a base table/synchronized materialized view involved in this modification.
SchemaVersion	Displays in M:N format. M represents the version of the Schema Change, and N represents the corresponding hash value. Each Schema Change increments the version.
TransactionId	Transaction ID for converting historical data.
State	The phase of the job.
	- PENDING: The job is waiting to be scheduled in the queue.
	- WAITING_TXN: Waiting for import tasks before the boundary transaction ID to complete.
	- RUNNING: Currently performing historical data conversion.
	- FINISHED: The job has successfully completed.
	- CANCELLED: The job has failed.
Msg	If the job fails, displays the failure message.
Progress	Job progress. Only displayed in RUNNING state. Progress is shown in M/N format. N is the total number of replicas involved in the Schema Change. M is the number of replicas for which historical data conversion has been completed.
Timeout	Job timeout in seconds.

Examples

1. Display the execution status of all modification column tasks for the default database.

   SHOW ALTER TABLE COLUMN;

2. Display the execution status of the most recent modification column task for a specific table.

   SHOW ALTER TABLE COLUMN WHERE TableName = "table1" ORDER BY CreateTime DESC LIMIT 1;

3. Display the execution status of creating or deleting ROLLUP tasks for a specified database.

   SHOW ALTER TABLE ROLLUP FROM example_db;

Keywords

SHOW, ALTER

Best Practices