MROBTCH
The MROBTCH system initialization parameter specifies how many events in a region can be accumulated in a batch before posting.
The region is started so that it can process the requests. The
batching of multiregion operation (MRO) requests includes some non-MRO
events:
- VSAM physical I/O completion events
- Subtasked request completion (mostly VSAM)
- DL/I request completion implemented through DBCTL
The value of the MROBTCH parameter can be
in the range of 1 through 255, and the default is 1. Using this batching
mechanism, you can spread the dispatch resource usage in CICS® over several tasks. If the value is greater
than 1 and CICS is in a system
wait, CICS is not posted for
dispatch until the specified number of events has occurred. Events
include MRO requests from connected systems or DASD I/O and CHANGE_MODE
processing. For these events, CICS is
dispatched after:
- The current batch fills up (the number of events equals MROBTCH)
- An ICV interval expires
During periods of low utilization, a value of MROBTCH greater than 1 can result in increased transaction response times. Transactions that issue I/O requests might be delayed because of an increased FCIOWAIT value. For more information about the effect of MROBTCH on performance, see Batching requests (MROBTCH).