Manually initiate a major compaction

You can manually initiate a major compaction.

Prerequisites

Before a major compaction is triggered, make sure that global major compaction is enabled. Global major compaction is controlled by the cluster-level parameter enable_major_freeze. The default value is True, which specifies to enable global major compaction.

If global major compaction is disabled for the current cluster, perform the following steps to enable this feature.

1. Log on to the sys tenant of the cluster as the root user.

2. Verify whether global major compaction is enabled.

   obclient> SHOW PARAMETERS LIKE 'enable_major_freeze';
   

3. If global major compaction is not enabled, execute the following statement to enable the feature.

   obclient> ALTER SYSTEM SET enable_major_freeze='True';
   

   For more information about the enable_major_freeze parameter, see enable_major_freeze.

Manually initiate a major compaction from the sys tenant

You can initiate a major compaction for the current tenant, all tenants, or specified tenants from the sys tenant.

Procedure:

1. Log on to the sys tenant of the cluster as the root user.

2. Execute the following statement to initiate a major compaction.

   SQL syntax:

   obclient> ALTER SYSTEM MAJOR FREEZE TENANT [=] ALL | tenant_name [, tenant_name ...];
   

   [=] indicates that the equal sign (=) is optional.

   Sample code:

   • Initiate a major compaction for the sys tenant

     obclient> ALTER SYSTEM MAJOR FREEZE TENANT;
     

   • Initiate a major compaction for all tenants

     obclient> ALTER SYSTEM MAJOR FREEZE TENANT = ALL;
     

   • Initiate a major compaction for specified tenants

     obclient> ALTER SYSTEM MAJOR FREEZE TENANT = tenant1,tenant2;
     

Manually initiate a major compaction for a user tenant

A user tenant can initiate a major compaction only for itself.

1. Log on to OceanBase Database as the administrator of the user tenant.

2. Initiate a major compaction for the current tenant.

   Sample statement:

   obclient> ALTER SYSTEM MAJOR FREEZE;
   

More information

• Automatically trigger a major compaction

• Configure scheduled major compactions

• Manually control a major compaction

• View the major compaction process