I have a TSO batch job that acts as an interface for MQ messages. When a message is received, the program will run and depending on the transaction type, other Cobol modules may be called.
One of these modules accesses a VSAM file. This module will be called once for each message received. The module contains a Cobol OPEN, READ using a key and CLOSE of that VSAM file.
My question is, does the Cobol OPEN statement refresh buffers associated with that VSAM file? i.e. For each call of that module, will the READ of the VSAM file be a physical read, or could it fetch a record from the buffer if it happens to be in the same Control Interval.