C.9.6. Oracle::Data Dictionary Cache

The Oracle::Data Dictionary Cache probe computes the Data Dictionary Cache Hit Ratio so as to optimize the SHARED_POOL_SIZE in init.ora. It collects the following metrics:
  • Data Dictionary Hit Ratio — The ratio of cache hits to cache lookup attempts in the data dictionary cache. In other words, the rate at which the database goes to the dictionary instead of the hard disk to retrieve data. A low ratio suggests more RAM should be added to the system.
  • Gets — The number of blocks accessed via single block gets (not through the consistent get mechanism).
  • Cache Misses — The number of accesses made to the block buffer to retrieve data in a consistent mode.

Table C.53. Oracle::Data Dictionary Cache settings

Field Value
Oracle SID*
Oracle Username*
Oracle Password*
Oracle Port* 1521
Timeout* 30
Warning Minimum Data Dictionary Hit Ratio
Critical Minimum Data Dictionary Hit Ratio