Upgrading to DB2 V9? Runstats Runstats Runstats

[Ed_Arnold]

I've seen a couple cases recently where CMOD has performed much worse after no change to CMOD, but an upgrade to DB2 V9.

This is a quote:

it appears that running                                               
runstats on our index data tables solved the problem. Even though there
were no deletes and no static binds, RUNSTATS was still necessary for 
these tables to account for change in cardinality. ....               
... Presumably this                                                   
was noticed when we migrated to version 9 because the optimization     
algorithms required greater accuracy of the catalog statistics.       
                                                                       

[Ed_Arnold]

Well well well --- and I just found this today:

 
DB2 9 migration: SQL performance best practices


http://www-01.ibm.com/support/docview.wss?rs=64&context=SSEPEK&q1=Db2+9+migration&uid=swg27015988

Well worth the read!