The CATALOGCACHE_SZ database configuration parameter specifies the amount of memory DB2 has available for storing information about defined objects (tables, indexes, etc). This memory is used to speed up prepare times for dynamic SQL and binds of static SQL.
When the Catalog Cache Hit Ratio is high, this is good because it means DB2 is avoiding I/O to the Catalog tables when preparing statements.
If the Catalog Cache Hit Ratio is less than 91%, consider increasing the CATALOGCACHE_SZ by 5% increments until a hit ratio of 95% or higher is achieved.