Calculating the EDM statement cache hit ratio
The EDM storage statistics provide information that can help you determine how successful your applications are at finding statements in the cache and in the catalog.
About this task
PREPARE REQUESTS ( A ) records the number of requests to search the cache. FULL PREPARES ( B ) records the number of times that a statement went through the optimization process to generate a new runtime structure, which can be interpreted as the number of times a statement was not found in the cache or catalog. LOOK-UP IN CATALOG ( C ) records the number of times that Db2 searched the statement in the catalog. To determine how often the dynamic statement was used from the cache, check the value in CACHE HIT RATIO ( D ). To determine how often a dynamic statement was used from the cache or from the catalog, check the value in CACHE+CATALOG HIT RATIO E .
Procedure
To calculate the EDM statement cache ratio
(PREPARE REQUESTS - (FULL PREPARES + LOOK-UP IN CATALOG)) / PREPARE REQUESTS = hit ratio
Example
The following figure shows the dynamic SQL statements part of the IBM OMEGAMON for Db2 Performance Expert on z/OS statistics report.
For more information, see the IBM® IBM OMEGAMON for Db2 Performance Expert on z/OS for Db2 Performance Expert on z/OS Report Reference.