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 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.

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.

More information

• Configure scheduled major compactions

• Manually initiate a major compaction

• Manually control a major compaction

• View the major compaction process