CANCEL ALTER TABLE

CANCEL ALTER TABLE cancels the execution of the ongoing ALTER TABLE operation, including:

• Modify columns.
• Optimize table schema (from v3.2), including modifying the bucketing method and the number of buckets.
• Create and delete the rollup index.

NOTICE

• This statement is a synchronous operation.
• This statement requires you to have the ALTER_PRIV privilege on the table.
• This statement only supports canceling asynchronous operations using ALTER TABLE (as mentioned above) and does not support canceling synchronous operations using ALTER TABLE, such as rename.

Syntax

CANCEL ALTER TABLE { COLUMN | OPTIMIZE | ROLLUP } FROM [db_name.]table_name

Parameters

• {COLUMN ｜ OPTIMIZE | ROLLUP}

  • If COLUMN is specified, this statement cancels operations of modifying columns.
  • If OPTIMIZE is specified, this statement cancels operations of optimizing table schema.
  • If ROLLUP is specified, this statement cancels operations of adding or deleting the rollup index.

• db_name: optional. The name of the database to which the table belongs. If this parameter is not specified, your current database is used by default.

• table_name: required. The table name.

Examples

1. Cancel the operation of modifying columns for example_table in the database example_db.

   CANCEL ALTER TABLE COLUMN FROM example_db.example_table;

2. Cancel the operation of optimizing table schema for example_table in the database example_db.

   CANCEL ALTER TABLE OPTIMIZE FROM example_db.example_table;

3. Cancel the operation of adding or deleting the rollup index for example_table in the current database.

   CANCEL ALTER TABLE ROLLUP FROM example_table;