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Appendix C. Probes 247
C.9.10. Oracle::Library Cache
The Oracle::Library Cache probe computes the Library Cache Miss Ratio so as to optimize
the SHARED_POOL_SIZE in
init.ora
. It collects the following metrics:
•
Library Cache Miss Ratio — The rate at which a library cache pin miss occurs. This
happens when a session executes a statement that it has already parsed but finds that the
statement is no longer in the shared pool.
•
Executions — The number of times a pin was requested for objects of this namespace.
•
Cache Misses — The number of pins of objects with previous pins since the object
handle was created that must now retrieve the object from disk.
Field Value
Oracle SID*
Oracle Username*
Oracle Password*
Oracle Port*
1521
Timeout* 30
Critical Maximum Library Cache Miss Ratio
Warning Maximum Library Cache Miss Ratio
Table C-57. Oracle::Library Cache settings
C.9.11. Oracle::Locks
The Oracle::Locks probe monitors an Oracle database instance and collects the following
metric:
•
Active Locks — The current number of active locks as determined by the value in the
v$locks table. Database administrators should be aware of high numbers of locks present
in a database instance.
Locks are used so that multiple users or processes updating the same data in the database do
not conflict. This probe is useful for alerting database administrators when a high number
of locks are present in a given instance.
Field Value