STATISTIC 

VARCHAR2(30) 

The name of the statistic: 

• Servers In Use: The number of PX servers currently performing parallel operations

• Servers Available: The number of PX servers available to perform parallel operations

• Servers Started: The number of times the system has had to create a PX server process

• Server Shutdown: The number of times a PX server process has been shutdown. A PX server process will be shutdown if it has not been used recently. The length of time it may remain "Available" is controlled by the initialization parameter PARALLEL_SERVER_IDLE_TIME

  If this value is large, consider increasing the parameter. This will increase performance due to avoiding the latency of PX server process creation

• Servers HWM: The maximum number of concurrent PX server processes

  If this number is equal to the initialization parameter PARALLEL_MAX_SERVERS, 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: The 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, it is recommended that the cause be determined

• Sessions: The total number of sessions created by all PX servers

• Memory Chunks Allocs: The number of large memory chunks allocated by PX servers

• Memory Chunks Freed: The number of large memory chunks freed

• Memory Chunks Current: The number of large memory chunks currently being used

• Memory Chunks HWM: The maximum number of concurrently allocated chunks

• Buffers allocated: The number of times a message buffer has been allocated

• Buffers freed: The number of times a message buffer has been freed

• Buffers Current: The number of message buffers currently being used

• Buffers HWM: The maximum number of concurrently allocated message buffers

VALUE 

NUMBER 

The value of the statistic