DB2 V10.5 FP5: CF self-tuning memory eliminates out of memory conditions

Starting in DB2® Version 10.5 Fix Pack 5, in a DB2 pureScale® environment, cluster caching facility (CF) self-tuning memory automatically and continuously reconfigures CF database memory. Unless specifically enabled, CF memory functions as before.

CF self-tuning memory is enabled by setting registry variable DB2_DATABASE_CF_MEMORY to AUTO. When enabled, CF self-tuning memory avoids out of memory conditions by tuning database memory parameters cf_db_mem_sz, cf_gbp_sz, cf_lock_sz, and cf_sca_sz. CF memory is shared by these parameters. The values of these four database memory parameters are interdependent.

In a multiple database environment, CF memory is configured automatically based on workload and available memory. Databases that are already active automatically give up CF memory for newly activated databases until a workload-based distribution of CF memory is reached. In addition, when a database is added, there is no downtime to reconfigure CF memory allocation.