DS_POOLSIZE configuration parameter

Use the DS_POOLSIZE parameter to specify the maximum number of entries in the data-distribution cache and other caches. The database server stores and accesses column statistics that the UPDATE STATISTICS statement generates in the MEDIUM or HIGH mode in the data-distribution cache.

onconfig.std value
DS_POOLSIZE 127
values
A positive value 127 or greater that represents half of the initial maximum number of entries in the cache. The maximum value is dependent upon the shared memory configuration and available shared memory for the server instance.
takes effect
After you edit your onconfig file and restart the database server.
When you increase the value in memory by running the onmode -wm command.
When you reset the value in memory by running the onmode -wm command.

Usage

Use the DS_HASHSIZE and the DS_POOLSIZE configuration parameters to improve performance of frequently run queries in a multi-user environment.

The initial number of entries in the cache is twice the value of the DS_POOLSIZE configuration parameter. For example, if the DS_POOLSIZE configuration parameter is set to 127, 254 entries are allowed in the cache. If all entries in a cache are full, the cache size automatically grows by 10%. To reduce the size of the cache, decrease the value of the DS_POOLSIZE configuration parameter in the onconfig file and restart the server.

The DS_POOLSIZE configuration parameter sets the number of entries in the following caches:

  • Data-distribution cache
  • Extend type name cache
  • Extended type ID cache
  • Cast cache
  • Operator class instance cache
  • Routine resolution cache
  • Aggregate cache
  • Secondary transient cache

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