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Download Performance Guide for IBM Informix Dynamic Server
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Data-Distribution Cache The onstat -g dic output has the following fields. Field Description Number of Lists Number of buckets that DD_HASHSIZE specifies Maximum List Size Number of tables allowed in each bucket List # Bucket number Size Number of tables in the bucket Ref cnt Number of times that users have used the data-dictionary information for this table from the cache Dirty Designation if the data-dictionary information is no longer valid Heap ptr Heap pointer Table name Name of the table that the data-dictionary information describes Data-Distribution Cache The optimizer uses distribution statistics generated by the UPDATE STATISTICS statement in the MEDIUM or HIGH mode to determine the query plan with the lowest cost. The first time that the optimizer accesses the distribution statistics for a column, the database server retrieves the statistics from the sysdistrib system catalog table on disk. Once the database server has accessed the distribution statistics, it places that information in the datadistribution cache in memory. Effect of Configuration on Memory Utilization 4-31
