MAJOR and MINOR

Purpose

This statement is used to initiate a major or minor compaction in a user tenant. Manual compaction supports tenant-level, table-level, and partition-level operations. Minor compaction supports tenant-level and partition-level operations.

Syntax

ALTER SYSTEM merge_action;

merge_action:
      MAJOR FREEZE [TABLE_ID = table_id | TABLET_ID = tablet_id]
    | MINOR FREEZE [TABLET_ID = tablet_id]
    | {SUSPEND | RESUME} MERGE
    | CLEAR MERGE ERROR

Parameters

Examples

Examples related to major compaction

• Initiates a major compaction for the user tenant.

  obclient> ALTER SYSTEM MAJOR FREEZE;
  Query OK, 0 rows affected
  

• Initiates a table-level major compaction for the user tenant.

  1. Query the table_id of the table tbl2 to be compacted.

     obclient(root@mysql001)[oceanbase]> SELECT database_name, table_id, table_name FROM oceanbase.DBA_OB_TABLE_LOCATIONS WHERE table_name = 'tbl2';
     

     The query result is as follows:

     +---------------+----------+------------+
     | database_name | table_id | table_name |
     +---------------+----------+------------+
     | test          |   500002 | tbl2       |
     +---------------+----------+------------+
     1 row in set
     

  2. Execute the following command to initiate a table-level major compaction.

     obclient(root@mysql001)[oceanbase]> ALTER SYSTEM MAJOR FREEZE TABLE_ID = 500002;
     

• Initiates a partition-level major compaction for the user tenant.

  1. Query the tablet_id of the partition to be compacted.

     obclient(root@mysql001)[oceanbase]> SELECT database_name, table_id, table_name, tablet_id, partition_name, subpartition_name FROM oceanbase.DBA_OB_TABLE_LOCATIONS WHERE table_name = 'tbl2';
     

     The query result is as follows:

     +---------------+----------+------------+-----------+----------------+-------------------+
     | database_name | table_id | table_name | tablet_id | partition_name | subpartition_name |
     +---------------+----------+------------+-----------+----------------+-------------------+
     | test          |   500010 | tbl2       |    200007 | p0             | NULL              |
     | test          |   500010 | tbl2       |    200008 | p1             | NULL              |
     | test          |   500010 | tbl2       |    200009 | p2             | NULL              |
     +---------------+----------+------------+-----------+----------------+-------------------+
     3 rows in set
     

  2. Execute the following command to initiate a partition-level major compaction.

     obclient(root@mysql001)[oceanbase]> ALTER SYSTEM MAJOR FREEZE TABLET_ID = 200007;
     

Examples of suspending or resuming a major compaction

• Suspends a major compaction for the user tenant.

  obclient> ALTER SYSTEM SUSPEND MERGE;
  Query OK, 0 rows affected
  

• Resumes a major compaction for the user tenant.

  obclient> ALTER SYSTEM RESUME MERGE;
  Query OK, 0 rows affected
  

Examples of clearing the error flag for a major compaction

• Clears the error flag for a major compaction for the user tenant.

  obclient> ALTER SYSTEM CLEAR MERGE ERROR;
  Query OK, 0 rows affected
  

Examples related to minor compaction

• Initiates a minor compaction for the user tenant.

  obclient> ALTER SYSTEM MINOR FREEZE;
  Query OK, 0 rows affected
  

• Initiates a partition-level minor compaction for the user tenant.

  obclient> ALTER SYSTEM MINOR FREEZE TABLET_ID = 5;
  Query OK, 0 rows affected