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Download Performance Guide for IBM Informix Dynamic Server
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Parameters That Affect Memory Caches Parameters That Affect Memory Caches The database server uses caches to store information in memory instead of performing a disk read to obtain the data or performing some other operation to create the information. These memory caches improve performance for multiple queries that access the same tables. You can specify configuration parameters to tune the effectiveness of each cache, as the following table shows. Configuration Parameter Configuration Parameter Description Stores information about (For details, refer to “Data- the table definition (such as column names and data Dictionary Cache” on types) page 4-29) DD_HASHSIZE Number of buckets in data dictionary cache DD_HASHMAX Number of tables that the database server can store in each bucket Data Distribution DS_POOLSIZE Total number of column distribution statistics that the database server can store in the data distribution cache DS_HASHSIZE Number of buckets in data distribution cache Cache Name Cache Description Data Dictionary Stores distribution (For details, refer to “Data- statistics for a column Distribution Cache” on page 4-31) (1 of 2) Effect of Configuration on Memory Utilization 4-27
