Display the blocker query in Timeout/Deadlock situations Merged

DB2 Timeouts and Deadlocks can cause significant problems for applications, and resolving them quickly is a high priority. Identifying the query that caused the deadlock or held locks long enough to cause a timeout is very important, with this info DBAs can quickly check access path and determine if we can tune it to avoid future deadlocks and timeouts.

DB2 Deadlocks and Timeouts result in SQL error -913. CQM captures information for the queries that are victims of the deadlock/timeout, but the winner/blocker queries complete successfully, and CQM doesn't make it easy for us to identify which query blocked access and caused a deadlock or a timeout.

DB2 Address Space provides the following information:

13.07.42 STC50701 DSNT375I :PZZI PLAN=DISTSERV WITH 153

153 CORRELATION-ID=PZZSRV11

153 CONNECTION-ID=SERVER

153 LUW-ID=0AD01111.BB3E.220613160708=46917

153

153 THREAD-INFO=PZZACC:10.208.140.50:346862345:DBAAGCC:DYNAMIC:1591:*:<10.2

153 08.6.98.47934.220613160708>

153 IS DEADLOCKED WITH PLAN=DISTSERV WITH

153 CORRELATION-ID=PZZSRV11

153 CONNECTION-ID=SERVER

153 LUW-ID=0AD01111.E91F.220613164950=69333

153

153 THREAD-INFO=PZZACC:10.208.140.50:193468808:DBAAGCC:DYNAMIC:1663:*:*

153 ON MEMBER PZZI

So it provides the number of the blocker query in the Dynamic Statement Cache, in this case - 1663. The problem is that we can't easily dump the cache when the timeout occurs, and by the time we dump it, the statement is often not in the cache anymore.

Here is our request: when we investigate a deadlock or a timeout, we want to be able to find the blocker query in the Current SQL Activity or in the Activity Summary for the right timeslot. DB2 knows the query (in the Address space it displays query number), so we would like to either add a Query Number column to CQM output, or have another easy and intuitive way to find the blocker query text.

Considering the fact that we sometimes investigate timeouts the next business day, it is important that this info is collected and kept in CQM. OMEGAMON is not the right tool for historical info.

Thank you.