Statistics for tuning and capacity planning

Capture statistics when the CICS Transaction Gateway is operating under a number of different operating conditions. This will help you understand changes that might affect the performance of the system.

CM_CALLOC

The current number of connection manager threads allocated to clients.

CM_CCURR

The current number of connection manager threads created. If this value is greater than the configuration parameter initconnect, it signifies the peak number of remote clients connected at any one time. This value cannot exceed the maximum number of connection managers defined in CM_SMAX.

CM_CWAITING

The current number of connection managers waiting for a worker thread to become available. This statistic shows the number of requests that are queuing in the Gateway daemon. It is usually low or zero in a well-tuned Gateway daemon. If it is higher than expected, consider increasing the maxworker configuration parameter.

CM_IALLOC

The number of allocations for connection manager threads representing the number of connections that have been established from remote clients. A low value represents efficient connection reuse.

CM_IALLOCHI

The peak number of connection manager threads concurrently allocated to client applications. This number represents a high water mark for CM_CALLOC.

CM_ICREATED

The number of connection manager threads created.

CM_ITIMEOUTS

The number of times that the Gateway daemon failed to allocate a connection manager thread to a client application within the defined connecttimeout length of time.

CM_LALLOC

The number of allocations for connection manager threads representing the number of connections that have been established from remote clients. A stable value represents efficient connection reuse.

CM_LTIMEOUTS

The number of times that the Gateway daemon failed to allocate a connection manager thread to a client application within the defined (connecttimeout) length of time. This statistic shows the number of incoming connection requests that have been refused. It is usually low or zero in a well-tuned Gateway daemon. If it is high, consider increasing the connecttimeout or maxconnect configuration parameters.

CM_SMAX

The maximum number of connection manager threads maxconnect that can possibly be created and allocated by the Gateway daemon. This value limits the number of Java™ clients that can be connected at any one time.

CS_CALLOC

The current number of allocated EXCI pipes across all CICS servers. Compare this value to the number of pipes available on this CICS Transaction Gateway; see CS_SLOGONLIM. If the number of pipes is close to the maximum available, it indicates that your CICS Transaction Gateway system is running near full capacity. Check that your CICS system can run with the maximum available 250 EXCI available pipes. If the number of EXCI pipes cannot support your workload, you might need to make more EXCI pipes available by running with multiple Gateway daemons.

There are some other reasons why you might be running with many EXCI pipes:

• The CICS transactions are relatively long-running and therefore occupy EXCI connections for longer.
• Your CICS Transaction Gateway system is using the pipe reuse model CTG_PIPE_REUSE=ALL, and is communicating with more than one CICS server. This model gives optimum performance. However, after a pipe has been allocated, it remains allocated to this particular server and is not available for use with other CICS servers. Consider using pipe model CTG_PIPE_REUSE=ONE or direct all CICS Transaction Gateway requests into a single CICS TOR; this can then route these requests into other CICS servers.

CS_ICOUNT

The number of CICS servers to which requests have been sent. This number equals the number of CICS servers in CS_ILIST.

CS_IREALLOC

The number of times that a worker thread has to deallocate its existing pipe and reallocate a new pipe because the existing pipe points to a different CICS server from that required by the request. This statistic applies only when the environment variable CTG_PIPE_REUSE is set to ONE. Cases where the pipe for the worker thread was deallocated and reallocated because the CICS server was not available are excluded.

CS_LCOUNT

The number of CICS servers to which requests have been sent. This number equals the number of CICS servers in CS_LLIST. The value of CS_LCOUNT can be useful when trying to understand EXCI pipe shortage problems. See CS_CALLOC.

CS_LREALLOC

The number of times that a worker thread has to deallocate its existing pipe and reallocate a new pipe because the existing pipe points to a different CICS server from that required by the request. This statistic is useful when determining how many additional EXCI pipe deallocate and allocate calls have occurred when using the pipe model CTG_PIPE_REUSE=ONE. The performance overhead of using CTG_PIPE_REUSE=ONE is small in the context of typical overall transaction costs, but if this value is high relative to the total number of requests (CS_LALLREQ), consider using the pipe reuse model CTG_PIPE_REUSE=ALL.

CS_SLOGONLIM

The maximum EXCI pipe allocation for each MVS address space. This value is the equivalent to the CICS subsystem initialization parameter LOGONLIM. You can use this value to verify the maximum number of EXCI pipes that are available to your CICS Transaction Gateway.

CSX_CALLOC

The current number of allocated EXCI pipes for CICS server x. See CS_CALLOC.

WT_CALLOC

The current number of worker threads that are being used by connection managers. Another way of viewing this value is the number of worker threads processing requests. If this value is close to WT_SMAX, consider increasing the maxworker configuration parameter.

If the CTG_PIPE_REUSE environment variable is set to ONE, increasing maxworker to the maximum number of EXCI connections available can allow for a higher throughput.

WT_CCURR

The current number of worker threads created. If this value is greater than the configuration parameter initworker, it signifies the peak number of parallel requests that have been in process at any one time. This value cannot exceed the maximum number of worker threads defined in WT_SMAX.

WT_IALLOCHI

The peak number of worker threads concurrently allocated to connection manager threads. This number represents a high water mark for WT_CALLOC.

WT_ITIMEOUTS

The number of times the Gateway daemon failed to allocate a worker thread to a connection manager within the defined workertimeout length of time.

WT_LTIMEOUTS

The number of times the Gateway daemon failed to allocate a worker thread to a connection manager within the defined workertimeout length of time. This number signifies that requests are timing out while queuing in the Gateway daemon. It is typically low or zero in a well-tuned Gateway daemon. If it is higher than expected, consider increasing the maxworker or workertimeout configuration parameters.

WT_SMAX

The maximum number of parallel requests maxworker that the Gateway daemon can process.