Manually initiate a minor compaction

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

Procedure

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

2. Select a proper minor compaction type as needed.

   • 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, the TENANT = all_user and TENANT = all settings express the same semantics. If you want an operation to take effect on all 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;
       

   • 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;
     

   • 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');
     

   • 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;
     Query OK, 0 rows affected
     

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

   • Minor compaction at the tablet level

     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 = tid;
     

     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 = tid;
     

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

     Here is an example:

     obclient> ALTER SYSTEM MINOR FREEZE TENANT = t1 tablet_id = 200001;
     Query OK, 0 rows affected
     
     obclient> ALTER SYSTEM MINOR FREEZE TENANT = t1 LS = 1001 tablet_id = 200001;
     Query OK, 0 rows affected
     

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