SOTUNING
The SOTUNING system initialization parameter specifies whether performance tuning for HTTP connections will occur to protect CICS® from unconstrained resource demand.
- SOTUNING={YES|520}
- Valid values are as follows:
- YES
-
As a region becomes overloaded, CICS will pause listening for new HTTP connection requests. While new connection requests are not being accepted, those pending requests will queue outside of CICS in the TCP/IP backlog queue. This backlog queue will increase when the region is over capacity, allowing feedback to TCP/IP port sharing and Sysplex Distributor, promoting a balanced sharing of workload with other regions that are sharing the same IP endpoint.
Because requests are no longer queuing in CICS, MXT will not be exceeded by a surge of HTTP requests, but the number of times MXT is reached might greatly increase. As CICS processes requests from the backlog queue, the number of active tasks will fluctuate, potentially reaching MXT multiple times.It does not mean that MXT needs to be increased, but indicates that the current value is correctly protecting CICS from unconstrained resource demand.
If the region continues to become overloaded, it will close existing persistent connections after their next request completes and new connections will be marked as non-persistent until the region is no longer under stress.
In addition, CICS will also periodically close persistent connections to allow more efficient sharing of workload across regions that share IP endpoints.
- 520
-
The CICS TS V5.2 behavior is used, and performance tuning for HTTP connections does not take place.