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
- on/true indicates the tagbucket adaption is enabled.
- off/false indicates the tagbucket adaption is disabled.
Default value: on
cache_tag_value_num
- 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
- on/true indicates that the table statistics are automatically collected.
- off/false indicates that the table statistics are not automatically collected.
Default value: off
![](https://support.huaweicloud.com/eu/IoTdevg-dws/public_sys-resources/note_3.0-en-us.png)
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.
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