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. The length of time it may remain "Available" is controlled by the PARALLEL_SERVER_IDLE_TIME initialization parameter.

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