MAJOR and MINOR

Description

This statement is used to initiate a major compaction or minor compaction (freeze) in the system tenant. You can manually initiate a major compaction at the tenant or partition level, and you can manually initiate a minor compaction at the tenant, zone, server, log stream, or partition level.

Syntax

ALTER SYSTEM merge_action;

merge_action:
      MAJOR FREEZE [tenant_list]
    | MAJOR FREEZE tenant_list TABLET_ID = tablet_id
    | MINOR FREEZE [tenant_list | TABLET_ID = tablet_id] [server_list] [zone_list] [LS [=] ls_id];
    | {SUSPEND | RESUME} MERGE [tenant_list]
    | CLEAR MERGE ERROR [tenant_list]

tenant_list:
    TENANT [=]  { all | all_user | all_meta } | tenant_name [, tenant_name ...]

server_list:
    SERVER [=] ('ip:port' [, 'ip:port'...])

zone_list:
    ZONE [=] ('zone_name' [, 'zone_name' ...]);

Parameter explanation

Considerations

A tablet corresponds to a partition. Therefore, note the following considerations when you initiate a major compaction at the partition level:

• You cannot initiate a major compaction for a partition on which a tenant-level major compaction is being performed.
• You cannot initiate a major compaction for a partition on which an adaptive scheduling major compaction is being performed.
• You cannot initiate a major compaction for a partition where the replicas are inconsistent.
• You cannot initiate a major compaction for a partition that is under restoration or being transferred.
• You cannot initiate a major compaction if a previous major compaction is suspended.
• A major compaction at the partition level is actually a major compaction for multiple replicas of the same partition. This process consumes CPU and disk I/O resources. Therefore, before you perform a major compaction at the partition level, you need to assess the resource usage of your tenant. After the command executes successfully, the CPU and I/O usage will increase.

Examples

Examples of major compactions

• Initiate a major compaction of the system tenant on a daily basis.

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

• Initiate a major compaction of all user tenants (excluding the system and metadata tenants).

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

• Initiate a major compaction of all metadata tenants.

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

• Initiate major compactions of the tenant1 and tenant2 tenants.

  obclient> ALTER SYSTEM MAJOR FREEZE TENANT = tenant1,tenant2;
  Query OK, 0 rows affected
  

Examples of minor compactions

• Initiate a minor compaction of the system tenant.

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

• Initiate a minor compaction of all user tenants (excluding the system and metadata tenants).

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

• Initiate a minor compaction of all metadata tenants.

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

• Initiate minor compactions of the tenant1 and tenant2 tenants.

  obclient> ALTER SYSTEM MINOR FREEZE TENANT = tenant1,tenant2;
  Query OK, 0 rows affected
  

• Initiate a minor compaction of a specified partition in the tenant1 tenant.

  obclient> ALTER SYSTEM MINOR FREEZE tenant = tenant1 tablet_id = 1100611139453887;
  Query OK, 0 rows affected
  

• Initiate a minor compaction of a specified OBServer node.

  obclient> ALTER SYSTEM MINOR FREEZE SERVER = ('10.XXX.XXX.XXX:2882');
  Query OK, 0 rows affected
  

• Initiate a minor compaction of a specified log stream in the tenant1 tenant.

  obclient> ALTER SYSTEM MINOR FREEZE tenant = t1 LS 1;
  Query OK, 0 rows affected
  

• Initiate a minor compaction of a specified partition in a specified log stream in the tenant1 tenant.

  obclient> ALTER SYSTEM MINOR FREEZE tenant = t1 ls 1 tablet_id = 60000;
  Query OK, 0 rows affected
  

Examples of suspending and resuming daily major compactions

• Suspend daily major compactions of all user tenants (excluding the system and metadata tenants).

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

• Suspend daily major compactions of the tenant1 and tenant2 tenants.

  obclient> ALTER SYSTEM SUSPEND MERGE TENANT = tenant1,tenant2;
  Query OK, 0 rows affected
  

• Suspend daily major compactions of all metadata tenants.

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

• Resume daily major compactions of all user tenants (excluding the system and metadata tenants).

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

• Resume daily major compactions of the tenant1 and tenant2 tenants.

  obclient> ALTER SYSTEM RESUME MERGE TENANT = tenant1,tenant2;
  Query OK, 0 rows affected
  

• Resume daily major compactions of all metadata tenants.

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

Examples of purging error markers

• Purge error markers of minor compactions of all user tenants (excluding the system and metadata tenants).

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

• Purge error markers of minor compactions of the tenant1 and tenant2 tenants.

  obclient> ALTER SYSTEM CLEAR MERGE ERROR TENANT = tenant1,tenant2;
  Query OK, 0 rows affected
  

• Purge error markers of minor compactions of all metadata tenants.

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

Initiate a major compaction at the partition level

1. Query the TABLET ID of the table.

   Here is an example:

   SELECT t1.tenant_id, t2.tenant_name, t1.database_name, t1.table_id, t1.table_name, t1.tablet_id, t1.PARTITION_NAME, t1.SUBPARTITION_NAME
   FROM oceanbase.CDB_OB_TABLE_LOCATIONS t1, oceanbase.DBA_OB_TENANTS t2
   WHERE t1.tenant_id=t2.tenant_id
   AND t1.table_name = 'test_tbl1'
   AND t2.tenant_name = 'oracle001';
   

   The return result is as follows:

   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   | tenant_id | tenant_name | database_name | table_id | table_name | tablet_id | PARTITION_NAME | SUBPARTITION_NAME |
   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200008 | P1             | SP0               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200009 | P1             | SP1               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200010 | P1             | SP2               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200011 | P1             | SP3               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200012 | P2             | SP4               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200013 | P2             | SP5               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200014 | P2             | SP6               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200015 | P2             | SP7               |
   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   8 rows in set
   

   For more information about the view columns, see oceanbase.CDB_OB_TABLE_LOCATIONS.

2. Initiate a major compaction.

   Here is an example:

   ALTER SYSTEM MAJOR FREEZE TENANT = oracle001 TABLET_ID = 200008;
   

   The return result is as follows:

   Query OK, 0 rows affected
   

Initiate a minor compaction at the partition level

1. Query the TABLET ID of the table.

   Here is an example:

   SELECT t1.tenant_id, t2.tenant_name, t1.database_name, t1.table_id, t1.table_name, t1.tablet_id, t1.PARTITION_NAME, t1.SUBPARTITION_NAME
   FROM oceanbase.CDB_OB_TABLE_LOCATIONS t1, oceanbase.DBA_OB_TENANTS t2
   WHERE t1.tenant_id=t2.tenant_id
   AND t1.table_name = 'test_tbl1'
   AND t2.tenant_name = 'oracle001';
   

   The return result is as follows:

   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   | tenant_id | tenant_name | database_name | table_id | table_name | tablet_id | PARTITION_NAME | SUBPARTITION_NAME |
   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200008 | P1             | SP0               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200009 | P1             | SP1               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200010 | P1             | SP2               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200011 | P1             | SP3               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200012 | P2             | SP4               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200013 | P2             | SP5               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200014 | P2             | SP6               |
   |      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200015 | P2             | SP7               |
   +-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
   8 rows in set
   

   For more information about the view columns, see oceanbase.CDB_OB_TABLE_LOCATIONS.

2. Initiate a minor compaction.

   Here is an example:

   ALTER SYSTEM MINOR FREEZE TENANT = oracle001 TABLET_ID = 200008;
   

   The return result is as follows:

   Query OK, 0 rows affected
   

References

• Overview
• Trigger a major compaction manually
• View the major compaction process
• Overview
• Trigger a minor compaction manually
• View the details of a minor compaction