IBM DB2 NUMDB value changes when migrating IBM Connections databases causing application problems

A very recent go live of IBM Connections 5.5 from 4.5 resulted in an error affecting Metrics. Metrics was not working what so ever.

A look at the cogserver.logs showed DB2 exceptions. I checked the DB2 client on the Cognos node, it could connect. I noticed that all the daily refreshes failed so it must have been database related.

I checked the value of the numdb having set the value to 25 after the databases were created prior to transfer of the 4.5 data. Running db2 get dbm cfg | find “NUMDB” gave me the value of 15 which is not what I set. I checked my notes and I did set it to 25.

I looked at db2diag.log and could see that the value changed at the time of go live, in fact it had changed after the databases were created and after I had changed the value to 25.

PID     : 7376                 TID : 3468           PROC : db2bp.exe
INSTANCE: DB2                  NODE : 000           DB   : HOMEPAGE
APPID   : *LOCAL.DB2.
HOSTNAME:
EDUID   : 3468
FUNCTION: DB2 UDB, config/install, sqlfLogUpdateCfgParam, probe:30
CHANGE  : CFG DBM: “Numdb” From: “25”  To: “15”

The above entry was at the same time that activity was happening with HOMEPAGE database.

I checked the scripts I had written and all seemed well. I then checked the lcwizard logs directory and found in C:\Users\db2admin\lcWizard\log\dbWizard\homepage_upgrade-50CR3-55.log the following

UPDATE DBM CFG USING NUMDB 15
DB20000I  The UPDATE DATABASE MANAGER CONFIGURATION command completed
successfully.

In ..\Wizards\connections.sql\homepage\db2\upgrade-50CR3-55.sql I found the culprit.

— —————————————————————–
— Defect 164873:
— —————————————————————–

UPDATE DBM CFG USING NUMDB 15@

I really have no idea why IBM would put that in there. There are 16 databases if you include FEBDB. Why have it for HOMEPAGE and not the other database scripts?

I updated the number of databases and then stopped all the application servers and restarted DB2 for good measure and all is well now.