DB2 Version 9.7 for Linux, UNIX, and Windows

cat_cache_size_top - Catalog cache high watermark monitor element

The largest logical size reached by the catalog cache.

Table 1. Snapshot Monitoring Information
Snapshot Level	Logical Data Grouping	Monitor Switch
Database	dbase	Basic

Table 2. Event Monitoring Information
Event Type	Logical Data Grouping	Monitor Switch
Database	event_db	-

Usage

This element indicates the maximum number of bytes the catalog cache required logically for the workload run against the database since it was activated.

The catalog cache is managed by logical size, which does not include memory management overhead. The pool_watermark element in the database snapshot provides the physical high water mark value for memory used by the catalog cache. The logical size rather than physical size should be used for catalog cache monitoring and tuning efforts.

If the catalog cache overflowed, then this element contains the largest size reached by the catalog cache during the overflow. Check the cat_cache_overflows monitor element to determine if such a condition occurred.

You can determine the minimum size of the catalog cache required by your workload by:

   maximum catalog cache size / 4096

Rounding the result up to a whole number, indicates the minimum number of 4K pages required by the catalog cache to avoid overflow.