Hi ,I have db2 v8.2 , installed on AIX 5.3 .
db cfg parameter MAXAPPLS configured on AUTOMATIC,
db cfg parameter CATALOGCACHE_SZ configured on MAXAPPLS*4

I'm asking if this configuration is recommended ,
and how can I tune the catalog cache hit ratio ?

Tks,

if there is no catalogcache overflow, then your current configuration should be fine. If there is overflow, then keep on increasing the configuration value until there is very minimal overflow. Moreover, the catalog cache hit ratio should be high enough , say > 85-90% to ensure that sufficient amount of memory is available.

Keep on taking DB Snapshot during the peak transaction volume to get a more representative figures for all of the above.

How would you calculate the catalog cache hit ratio?

100 - ( Catalog cache inserts * 100 / Catalog cache lookups )

these are health_indicators. where did you find the values for these elements ?

Hi,

If MAXAPPLS configured on AUTOMATIC and CATALOGCACHE_SZ configured on MAXAPPLS*4, it means that this parameter is actually an automatic also.

So how to increase this parameter is set automatically? Is there a disability for automatic parameter?

if you are not getting any error mentioning about you have exceeded limit for maximum applications, then your current setting is fine. In case you give the CFG parameter a hard value e.g. 400 to start with, then you are disabling the automatic parameter.

Similarly for Catalog cache by default you have values of -1, so if you give it a fix value say 64 4 K page, you are disabling automatic feature for it.

From the snapshot of Database, you can monitor and find out whether your current value is fine. Moreover for a overflow condition, your diaglog will also be reported with Catalog Cache overflow errors.