DB2 FOR LUW / DB2FORLUW / 950 - DB2

If an OLAP query has a row that is wider than 65535 bytes, then 
it may cause a memory corruption and crash. OLAP queries require 
the buffering of data in memory, but a logic problem when 
computing the buffer size causes DB2 to chose a buffer size that 
is too small to contain the wide row. This later results in 
memory corruption when the row gets copied into the 
insufficiently sized buffer, thereby overwriting information 
beyond that buffer in memory. 
 
Since this is a memory corruption, there is not always a 
consistent problem signature to uniquely identify the case since 
it depends on what information gets corrupted. If a memory debug 
setting is used, like db2set DB2MEMDBG=PROTECT, then the 
corruption can be caught at the time of the overwrite, with the 
following stack traceback: 
 
sqlri_buffer_add 
sqlri_scalag 
sqlriSectInvoke 
sqlrr_process_fetch_request 
sqlrr_open

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* USERS AFFECTED:                                              * 
* ALL                                                          * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* See SYSROUTE APARs to see where this APAR is addressed       * 
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Reduce the width of the row flowing into scalag, or rewrite the 
query so that it doesn't select rows wider than 65535 bytes.

not known / see Local fix

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

16.09.2013
09.05.2017
09.05.2017