Entering content frame

 Catalog cache hitrate 

Catalog cache hitrate <percentage>%, <number> of <number> accesses failed

Explanation

The hit rate when accessing the catalog cache in which the parsed SQL statements are administered is too low. In a running database application, the catalog cache hit rate should be about 90%. If new program parts or programs are started, the hit rate can temporarily sink to a very low level. However, the average over 15 minutes should not be below 85%.

User Response

The size of the catalog cache should be about 100 pages for each database session. You can check this with the general database parameter MAXUSERTASKS and the special database parameter CAT_CACHE_SUPPLY.

The catalog cache is enlarged dynamically by the active database sessions, and released again with a RELEASE statement. You can determine the current cache sizes with the SQL statement SELECT * FROM CONNECTEDUSERS.

If sessions need significantly more than 100 pages, we recommend that you increase the catalog cache accordingly in the medium term, if the memory of the server is large enough.

 

Leaving content frame