DB2 FOR LUW / DB2FORLUW / 970 - DB2

In case you use PREFETCHSIZE AUTOMATIC with AUTOMATIC STORAGE, 
there could be a miscalculation of the PREFETCH SIZE used. 
The intention of this APAR is to fix the the prefetch size 
calculation. 
However, there is a more subtle and complex issue here.  In our 
design, each table has a packed descriptor and the packed 
descriptor contains a bunch of information including the 
tablespace's prefetch size.  When the tablespace's prefetch size 
changes, we need to update the packed descriptors of ALL the 
tables and indexes within this tablespace.  This is a complex 
issue because the packed descriptors are stored in the system 
catalog.  This is how it's done in the ALTER TABLESPACE 
PREFETCHSIZE codepath.  However, the automatic storage codepath 
does not have the infrastructure to do all these. Fixing this is 
too risky to be done in an APAR fix. There is a simple 
workaround available: 
 
1. ALTER TABLESPACE PREFETCHSIZE <some number> 
2. ALTER TABLESPACE PREFETCHSIZE AUTOMATIC "

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* USERS AFFECTED:                                              * 
* All                                                          * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 9.7 Fix Pack 6.                       * 
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1. ALTER TABLESPACE PREFETCHSIZE <some number> 
2. ALTER TABLESPACE PREFETCHSIZE AUTOMATIC " 
 
NOTE: Workaround is good till new stripe set is not created. 
Once containers get filled and new stripe set needs to be 
created, then prefetch size will be miscalculated again.

DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

First fixed in DB2 Version 9.7 Fix Pack 6.

not known / see Local fix

forerunner  : APAR is sysrouted TO one or more of the following: IC84583 
follow-up : 

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

05.01.2012
06.06.2012
22.06.2012

9.7.FP6