Manually initiate a minor compaction

You can execute the ALTER SYSTEM MINOR FREEZE statement in the sys tenant or a user tenant to manually initiate a minor compaction at the tenant, zone, server, log stream, or partition level.

Initiate a minor compaction from the sys tenant

You can initiate a minor compaction at the tenant, zone, server, log stream, or tablet level from the sys tenant.

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

2. Select a proper minor compaction type as needed.

   • Initiate a minor compaction at the tenant level

     You can initiate a minor compaction for one or more tenants by using the following SQL syntax:

     obclient> ALTER SYSTEM MINOR FREEZE TENANT [=] all_user | all | all_meta | tenant_name [, tenant_name ...];
     

     Here are some examples:

     • Initiate a minor compaction for the sys tenant

       obclient> ALTER SYSTEM MINOR FREEZE;
       

     • Initiate a minor compaction for all user tenants from the sys tenant

       obclient> ALTER SYSTEM MINOR FREEZE TENANT = all_user;
       

       or

       obclient> ALTER SYSTEM MINOR FREEZE TENANT = all;
       

       Note

       In OceanBase Database V4.2.1 and later, TENANT = all_user and TENANT = all express the same semantics. If you want an operation to take effect on all user tenants, we recommend that you use TENANT = all_user. TENANT = all will be deprecated.

     • Initiate a minor compaction for all meta tenants from the sys tenant

       obclient> ALTER SYSTEM MINOR FREEZE TENANT = all_meta;
       

     • Initiate a minor compaction for a specified tenant from the sys tenant

       obclient> ALTER SYSTEM MINOR FREEZE TENANT = tenant1;
       

   • Initiate a minor compaction at the zone level

     You can initiate a minor compaction for a specified zone by using the following SQL syntax:

     obclient> ALTER SYSTEM MINOR FREEZE ZONE [=] zone_name;
     

     Here is an example:

     obclient> ALTER SYSTEM MINOR FREEZE ZONE = zone1;
     

   • Initiate a minor compaction at the server level

     You can initiate a minor compaction for one or more specified OBServer nodes by using the following SQL syntax:

     obclient> ALTER SYSTEM MINOR FREEZE SERVER = ('ip:port' [, 'ip:port'...]);
     

     Here is an example:

     obclient> ALTER SYSTEM MINOR FREEZE SERVER = ('xx.xx.xx.xx:2882','xx.xx.xx.xx:2882');
     

   • Initiate a minor compaction at the log stream level

     You can initiate a minor compaction for a specified log stream of a specified tenant by using the following SQL syntax:

     ALTER SYSTEM MINOR FREEZE TENANT [=] tenant_name LS [=] ls_id;
     

     In the syntax, tenant_name specifies the name of a tenant and ls_id specifies the ID of a log stream in the tenant. You can query the oceanbase.CDB_OB_TABLET_TO_LS view for IDs of log streams.

     Here is an example:

     obclient> ALTER SYSTEM MINOR FREEZE TENANT = t1 LS = 1001;
     

     After you execute this statement, the system performs a minor compaction for all tablets in the specified log stream of the specified tenant.

   • Initiate a minor compaction at the partition level

     In OceanBase Database, one partition corresponds to one tablet.

     You can initiate a minor compaction for a specified tablet in a specified tenant by using the following SQL syntax:

     ALTER SYSTEM MINOR FREEZE TENANT [=] tenant_name TABLET_ID = tablet_id;
     

     Alternatively, you can initiate a minor compaction for a specified tablet in a specified log stream of a specified tenant by using the following SQL syntax:

     ALTER SYSTEM MINOR FREEZE TENANT [=] tenant_name LS [=] ls_id TABLET_ID = tablet_id;
     

     In the syntax, tenant_name specifies the name of a tenant, ls_id specifies the ID of a log stream in the tenant, and tablet_id specifies the ID of a tablet in the log stream. You can query the CDB_OB_TABLE_LOCATIONS view for IDs of log streams and tablets. For more information about columns in the CDB_OB_TABLE_LOCATIONS view, see oceanbase.CDB_OB_TABLE_LOCATIONS.

     The following example shows how to initiate a minor compaction for a specified tablet in a specified tenant:

     obclient> ALTER SYSTEM MINOR FREEZE TENANT = tenant1 TABLET_ID = 200001;
     

     The following example shows how to initiate a minor compaction for a specified tablet in a specified log stream of a specified tenant:

     obclient> ALTER SYSTEM MINOR FREEZE TENANT = tenant1 LS = 1001 TABLET_ID = 200001;
     

Initiate a minor compaction from a user tenant

You can initiate a minor compaction only for the current tenant at the tenant level or partition level from a user tenant.

1. Log on to a MySQL or Oracle tenant of the cluster as the administrator of the tenant.

2. Select a proper minor compaction type as needed.

   • Initiate a minor compaction at the tenant level

     obclient> ALTER SYSTEM MINOR FREEZE;
     

   • Initiate a minor compaction at the partition level

     In OceanBase Database, one partition corresponds to one tablet.

     You can initiate a minor compaction for a specified tablet in the current tenant by using the following SQL syntax:

     ALTER SYSTEM MINOR FREEZE TABLET_ID = tablet_id;
     

     In the syntax, tablet_id can be queried from the DBA_OB_TABLE_LOCATIONS view. For more information about columns in the DBA_OB_TABLE_LOCATIONS view, see DBA_OB_TABLE_LOCATIONS.

     Here is an example:

     obclient> ALTER SYSTEM MINOR FREEZE TABLET_ID = 200001;
     

What to do next

After you initiate a minor compaction, you can view the information about it. For more information, see View minor compaction information.

References

• Automatically trigger a minor compaction

• Modify minor compaction settings