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Version: Latest-3.3

SHOW ALTER TABLE

Description

Shows the execution of the ongoing ALTER TABLE operations, 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.

Syntax

  • Show the execution of operations of modifying columns or optimizing table schema.

    SHOW ALTER TABLE { COLUMN | OPTIMIZE } [FROM db_name] [WHERE TableName|CreateTime|FinishTime|State] [ORDER BY] [LIMIT]
  • Show the execution of operations of adding or deleting the rollup index.

    SHOW ALTER TABLE ROLLUP [FROM db_name]

Parameters

  • {COLUMN | OPTIMIZE | ROLLUP}:

    • If COLUMN is specified, this statement shows operations of modifying columns.
    • If OPTIMIZE is specified, this statement shows operations of optimizing table structure.
    • If ROLLUP is specified, this statement shows operations of adding or deleting the rollup index.
  • db_name: optional. If db_name is not specified, the current database is used by default.

Examples

  1. Show the execution of operations of modifying columns, optimizing table schema, and creating or deleting the rollup index in the current database.

    SHOW ALTER TABLE COLUMN;
    SHOW ALTER TABLE OPTIMIZE;
    SHOW ALTER TABLE ROLLUP;
  2. Show the execution of operations related to modifying columns, optimizing table schema, and creating or deleting the rollup index in a specified database.

    SHOW ALTER TABLE COLUMN FROM example_db;
    SHOW ALTER TABLE OPTIMIZE FROM example_db;
    SHOW ALTER TABLE ROLLUP FROM example_db;
  3. Show the execution of the most recent operation of modifying columns or optimizing table schema in a specified table.

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

References