Help Center> Data Warehouse Service (DWS)> Stream Data Warehouse> Stream Data Warehouse GUC Parameters
Updated on 2023-08-23 GMT+08:00
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Stream Data Warehouse GUC Parameters

enable_tagbucket_auto_adapt

Parameter description: Specifies whether to enable tagbucket adaption. If this parameter is enabled, the tag column that is frequently used in the query statement in the current time period is optimized, and the query statements that contain the tag column in its where condition are accelerated.

Type: POSTMASTER

Value range: Boolean
  • on/true indicates the tagbucket adaption is enabled.
  • off/false indicates the tagbucket adaption is disabled.

Default value: on

cache_tag_value_num

Parameter description: Specifies the number of cached tag tuples in the tag column lateread scenario. The speed of loading data from the cache is faster, which improves the query performance.
  • If the tag tuples in the tag table after being filtered is less than or equal to the value of this parameter, they are loaded to the memory for cache.
  • Otherwise, they are not loaded.

Type: USERSET

Value range: an integer ranging from 0 to 60000

Default value: 60000

tag_cache_max_number

Parameter description: Specifies the maximum value of the tag cache.

Type: POSTMASTER

Value range: an integer ranging from 100000 to INT MAX

Default value: 10000000

autovacuum_vacuum_cost_delay

Parameter description: Specifies the value of the cost delay used in the VACUUM operation.

Type: SIGHUP

Value range: an integer ranging from –1 to 100. The unit is ms. -1 indicates that the normal vacuum cost delay is used.

Default value: 0

autoanalyze

Parameter description: Specifies whether to automatically collect statistics on tables that have no statistics when a plan is generated. If an exception occurs in the database during the execution of autoanalyze on a table, after the database is recovered, the system may still prompt you to collect the statistics of the table when you run the statement again. Then, you need to manually perform the analyze operation.

Type: SUSET

Value range: Boolean
  • on/true indicates that the table statistics are automatically collected.
  • off/false indicates that the table statistics are not automatically collected.

Default value: off

Currently, the autoanalyze feature is not available for foreign tables and temporary tables with the ON COMMIT [DELETE ROWS|DROP] option. If you need the statistics, manually perform the ANALYZE operation.