The following are the different methods can be used to know Buffer usage and the kind of database calls used in the IMS programs.
The IMS monitor, to gather details of buffer usage and database calls over a specified time period in an IMS subsystem.
- The //DFSSTAT DD card, used in batch JCL to provide a summary of buffer usage and database calls.
- As there is very little overhead in including this (the details printed to the DD at region termination are accumulated by the IMS region controller whether they are output or not), it is normally worthwhile putting this in all batch jobs.
- Running the DB monitor on a batch job, to collect similar details to the IMS monitor in an online system. As there is an overhead on running this, it would normally only be turned on when specific problems are being investigated.