Automatically trigger a major compaction

A major compaction can be automatically triggered.

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 that 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.

Conditions for triggering an automatic major compaction

A major compaction is automatically triggered if the memory usage of the MemTable of a tenant reaches the value of the freeze_trigger_percentage parameter and the number of minor compactions reaches the value of the major_compact_trigger parameter.

For more information about the freeze_trigger_percentage and major_compact_trigger parameters, see Modify minor compaction settings.

References

• Configure scheduled major compactions

• Manually initiate a major compaction

• Manually control a major compaction

• View the major compaction process