V$PX_PROCESS_SYSSTAT

V$PX_PROCESS_SYSSTAT contains information about the sessions running parallel execution.

Column	Datatype	Description
STATISTIC	VARCHAR2(30)	Name of the statistic: Servers In Use - Number of PX servers currently performing parallel operations Servers Available - Number of PX servers available to perform parallel operations Servers Started - Number of times the system has had to create a PX server process Servers Shutdown - Number of times a PX server process has been shut down. A PX server process will be shut down if it has not been used recently. If this value is large, then consider increasing the parameter. This will improve performance by avoiding the latency of PX server process creation. Servers HWM - Maximum number of concurrent PX server processes If this number is equal to the PARALLEL_MAX_SERVERS initialization parameter, then consider increasing the parameter. This could allow you to increase your throughput, especially if your system is under-utilized and the V$SYSSTAT statistic "Parallel operations downgraded to serial" is large. Servers Cleaned Up - Number of times PMON had to clean up a PX server. This should only happen during abnormal termination of a parallel operation. If this number is large, then you should determine the cause. Server Sessions - Total number of sessions created by all PX servers Memory Chunks Allocated - Number of large memory chunks allocated by PX servers Memory Chunks Freed - Number of large memory chunks freed Memory Chunks Current - Number of large memory chunks currently being used Memory Chunks HWM - Maximum number of concurrently allocated chunks Buffers allocated - Number of times a message buffer has been allocated Buffers freed - Number of times a message buffer has been freed Buffers Current - Number of message buffers currently being used Buffers HWM - Maximum number of concurrently allocated message buffers
VALUE	NUMBER	Value of the statistic

Oracle data dictionary views

Oracle dynamic performance views

Last updated: 2009-11-05 Thursday

V$LIBRARYCACHE

V$LIBRARYCACHE contains statistics about library cache performance and activity.

Column	Datatype	Description
NAMESPACE	VARCHAR2(15)	Library cache namespace
GETS	NUMBER	Number of times a lock was requested for objects of this namespace
GETHITS	NUMBER	Number of times an object's handle was found in memory
GETHITRATIO	NUMBER	Ratio of GETHITS to GETS
PINS	NUMBER	Number of times a PIN was requested for objects of this namespace
PINHITS	NUMBER	Number of times all of the metadata pieces of the library object were found in memory
PINHITRATIO	NUMBER	Ratio of PINHITS to PINS
RELOADS	NUMBER	Any PIN of an object that is not the first PIN performed since the object handle was created, and which requires loading the object from disk
INVALIDATIONS	NUMBER	Total number of times objects in this namespace were marked invalid because a dependent object was modified
DLM_LOCK_REQUESTS	NUMBER	Number of GET requests lock instance locks
DLM_PIN_REQUESTS	NUMBER	Number of PIN requests lock instance locks
DLM_PIN_RELEASES	NUMBER	Number of release requests PIN instance locks
DLM_INVALIDATION_REQUESTS	NUMBER	Number of GET requests for invalidation instance locks
DLM_INVALIDATIONS	NUMBER	Number of invalidation pings received from other instances

Oracle data dictionary views

Oracle dynamic performance views

Last updated: 2009-11-05 Thursday

V$LIBRARY_CACHE_MEMORY

V$LIBRARY_CACHE_MEMORY

V$LIBRARY_CACHE_MEMORY displays information about memory allocated to library cache memory objects in different namespaces. A memory object is an internal grouping of memory for efficient management. A library cache object may consist of one or more memory objects.

Column	Datatype	Description
LC_NAMESPACE	VARCHAR2(15)	Library cache namespace
LC_INUSE_MEMORY_OBJECTS	NUMBER	Number of library cache memory objects currently in use in the shared pool
LC_INUSE_MEMORY_SIZE	NUMBER	Total size of library cache in-use memory objects (in megabytes)
LC_FREEABLE_MEMORY_OBJECTS	NUMBER	Number of freeable library cache memory objects in the shared pool
LC_FREEABLE_MEMORY_SIZE	NUMBER	Size of library cache freeable memory objects (in megabytes)

Oracle data dictionary views

Oracle dynamic performance views

Last updated: 2009-11-05 Thursday