The Catalog Cache Hit Ratio (CATHR)
CATHR = 100 - ( Catalog cache inserts * 100 / Catalog cache lookups )
Use file 'dbsnap2.txt' or a Database Snapshot to file your values for Catalog cache inserts and lookups. Inserts are analogous to Bufferpool Physical Reads, and lookups are analogous to Bufferpool Logical Reads. Why IBM had to call these Inserts and Lookups instead of Physical Reads and Logical Reads is another of the world's greatest mysteries.
Anyway, the objective here is to avoid as many trips to disk (Inserts) as possible so that the requests for data (Lookups) can be satisfied from memory - this will greatly speed up the preparation of your dynamic SQL.
The Catalog Cache Hit Ratio should generally be at least 95%, and most shops are able to achieve this rather easily.
If you find that your CATHR is less than 95%, then you will want to increase DB CFG parameter CATALOGCACHE_SZ in gradual 5% increments, or 16 4K pages, whichever is greater, until such time as you successfully achieve the 95% goal.
The Shameless Marketing Moment
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Also, be sure to check out DBI's next Webinar which covers DB2 LUW Index Design Tips and Techniques... October 11th... see DBI website for details: www.database-brothers.com
Just for Fun
I found an interesting DB2 related web site the other day. The main URL is www.justdb2.com - no worries if you get forwarded or re-directed to www.db2wisconsin.com ... the web site author apparently owns multiple domains. Do you know of another interesting or helpful DB2 related web site? Please post a comment.
With best regards, Scott