# Collect major compaction parameter settings

# Collect major compaction parameter settings

Description

You can query the settings of parameters related to major compactions.

Statement

OceanBase Database of a version earlier than V4.0.0:

SELECT NULL tenant_id,zone,svr_ip,svr_port,name,value,info,section,scope,edit_level 
                              FROM __all_virtual_sys_parameter_stat 
                              WHERE name IN (
                                  'merge_thread_count', 
                                  'minor_freeze_times',
                                  'zone_merge_timeout',
                                  'zone_merge_concurrency',
                                  'default_progressive_merge_num',
                                  'merger_check_interval'
                              )

OceanBase Database V4.0.0 and later:

SELECT tenant_id,zone,svr_ip,svr_port,name,value,info,section,scope,edit_level 
                            FROM __all_virtual_tenant_parameter_info 
                            WHERE name IN (
                                'compaction_low_thread_score', 
                                'major_freeze_duty_time',
                                'major_compact_trigger',
                                'default_progressive_merge_num',
                                'merger_check_interval'
                            )

The parameters are described as follows:

• merge_thread_count: the number of worker threads for the daily major compaction.
• minor_freeze_times: the number of minor compactions that triggers a global major compaction.
• zone_merge_timeout: the timeout period for the major compaction of a zone.
• zone_merge_concurrency: the number of zones that can be compacted in parallel in a major compaction. If this parameter is set to 0, the system determines the best degree of parallelism based on the actual deployment status.
• default_progressive_merge_num: the default number of progressive major compaction rounds for a new table.
• merger_check_interval: the interval for scheduling the thread for checking the major compaction status.
• compaction_low_thread_score: the weight of CPU time slices occupied by the worker threads for low-priority compaction tasks.
• major_freeze_duty_time: the time to trigger a freeze and a major compaction every day.
• major_compact_trigger: the number of minor compactions that triggers a global major compaction.