Spotlight on SAP ASE 2.12 - User Guide

Data Cache Hit Rate

The hit rate reports the percentage of cache hits compared to the total number of cache searches. This value is a summary of the default data cache and all the named caches combined. 

Diagnosing a cache hit rate requires an understanding of how the application uses each cache. In caches that are created to hold specific objects, such as an index or a look up table, cache hit ratios may reach 100%. In caches used for random point queries on very large tables, cache hit ratios may be quite low but still represent an effective use of the cache.

To determine how effective the overall cache design for this server is, wait until the load on a server has been normalized.

See the Data Cache tab on the Memorydrilldown if the cache hit rate is high. Investigate the individual data cache's performance statistics.