Connection persistence statistics
By default, CICS® attempts to keep HTTP connections open as persistent connections. From TCP/IP statistics, you can obtain a view of connection persistence for a CICS region and for connections into a specific TCPIPSERVICE.
Obtaining a view of connection persistence for a CICS region
The following statistics in TCP/IP Global statistics provide a view of connection persistence for a CICS region:
- Inbound
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- Total number of inbound sockets created (SOG_INB_SOCKETS_CREATED)
- The total number of inbound sockets created
- Total number of non-persistent inbound sockets created (SOG_NPERS_INB_SOCKETS_CREATED)
- The total number of non-persistent inbound sockets created
- Current number of inbound sockets (SOG_CURR_INBOUND_SOCKETS)
- The current number of inbound sockets
- Current number of non-persistent inbound sockets (SOG_CURR_NPERS_INB_SOCKETS}
- The current number of non-persistent inbound sockets
- Current number of persistent inbound sockets (calculated for the reports)
- The current number of persistent inbound sockets
- Peak number of inbound sockets (SOG_PEAK_INBOUND_SOCKETS)
- The peak number of inbound sockets
- Peak number of non-persistent inbound sockets (SOG_PEAK_NPERS_INB_SOCKETS)
- The peak number of non-persistent inbound sockets
- Peak number of persistent inbound sockets (SOG_PEAK_PERS_INB_SOCKETS)
- The peak number of persistent inbound sockets
- Outbound
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- Total number of outbound sockets created (SOG_OUTB_SOCKETS_CREATED)
- The total number of outbound sockets created
- Total number of persistent outbound sockets created (SOG_PERS_OUTBOUND_CREATED)
- The total number of persistent outbound sockets created
- Current number of non-persistent outbound sockets (SOG_CURR_OUTB_SOCKETS)
- The current number of non-persistent outbound sockets
- Current number of persistent outbound sockets (SOG_CURR_PERS_OUTB_SOCKETS)
- The current number of persistent outbound sockets
- Peak number of outbound sockets (SOG_PEAK_BOTH_OUTB_SOCKETS)
- The peak number of outbound sockets
- Peak number of non-persistent outbound sockets (SOG_PEAK_OUTB_SOCKETS)
- The peak number of non-persistent outbound sockets
- Peak number of persistent outbound sockets (SOG_PEAK_PERS_OUTB_SOCKETS)
- The peak number of persistent outbound sockets
Obtaining a view of connection persistence for connections into a TCPIPSERVICE
The following statistics in TCP/IP services: Resource statistics can give you a view of connection persistence for connections into a specific TCPIPSERVICE:
- Total Connections (SOR_TOTAL_CONNS)
- The total number of connections made for the TCP/IP service
- Non-Persistent Connections (SOR_TCPIPS_NON_PERSIST)
- The number of connections where CICS did not allow the Web client to have a persistent connection
- Maximum Persistent Connections (SOR_TCPIPS_MAX_PERSIST)
- The maximum number of persistent connections from Web clients that the CICS region accepts at any one time
- Made non-persistent at MAXPERSIST (SOR_NONP_AT_MAXPERSIST)
- The number of times a new persistent connection was made non-persistent because MAXPERSIST was reached
- Requests processed (SOR_REQUESTS)
- The number of requests processed by the TCP/IP service
Many factors control connection persistence. For details, see How CICS web support handles persistent connections. Note that IPIC connections are always persistent. If there are suddenly a lot more non-persistent connections than normal, check whether performance tuning temporarily disallowed connection persistence so that the region could recover from overloading. For more information, see Performance tuning statistics.
As non-persistent connections are by definition single use only, you can use the TCPIPSERVICE statistics fields to calculate how many times persistent connections were reused:
Number of requests processed by existing persistent connections = Requests processed (SOR_REQUESTS) - Total Connections (SOR_TOTAL_CONNS)