Actions to reduce/improve waits on IDMS log

Products

• IDMS
• IDMS - Database

Issue/Introduction

In IDMS Performance Monitor and in Prealert seeing waits on the log. What tuning actions can be performed to reduce/improve the waits?

Environment

IDMS 19.0

Resolution

There are 2 possible waits relating to the log files, DCLOG single thread wait and Log full wait.

Documentation section Event Control Block (ECB) Information, explains each wait and what can be done about it.

5     CSALFECB    DCLOG single thread wait

Reduce the number of user writes to logs, if any.

Only allow critical dumps to be written to the log.

If using Perfmon on z/OS, write the records to SMF.

If using Perfmon, reduce statistics collection to a minimum.

Move the log area to faster device.

Balance channels.

Balance packs.

 

133  CSALGECB    Log full ECB    

Wait for a batch job to offload the log.

CV waits while waiting for the offload.

If this wait is prolonged, tasks will timeout.

Check that the manual procedures are being followed properly. Verify the log is not being overused.

Send statistics to SMF rather than to the log.

Turn off snaps.