Oracle Parallel Processing

Monitoring and Tuning IDLM

The Integrated Distributed Lock Manager is responsible for maintaining a list of database resources and for allocating locks on those resources. IDLM coordinates lock requests from different OPS instances. In some cases, lock requests are granted immediately, while in other cases lock requests are queued up until the remote instance that holds the lock in a conflicting mode releases the lock. The views that return information about IDLM performance are summarized in Table 10.8.

Table 10-8. Views with IDLM Statistics

Dynamic View	Description
V$DLM_CONVERT_LOCAL GV$DLM_CONVERT_LOCAL	Returns the counts for different types of local lock mode conversions, as well as the time taken for those conversions
V$DLM_CONVERT_REMOTE GV$DLM_CONVERT_REMOTE	Returns the counts for different types of lock mode conversions in a remote node, as well as the time taken for those conversions
V$DLM_LATCH GV$DLM_LATCH	Returns IDLM latch statistics
V$DLM_MISC GV$DLM_MISC	Returns some miscellaneous IDLM statistics
V$DLM_RESS GV$DLM_RESS	New in Oracle8i; returns information on all resources known to IDLM
V$DLM_ALL_LOCKS GV$DLM_ALL_LOCKS	New in Oracle8i; returns information on all locks known to IDLM
V$DLM_LOCKS GV$DLM_LOCKS	New in Oracle8i; returns a subset of results of the V$DLM_ALL_LOCKS view and return information on all locks that are either blocked or blocking others

Tuning IDLM

IDLM has internal data structures that contain lists of all database resources. IDLM ...