DB2 FOR LUW / DB2FORLUW / A50 - DB2

If you execute multiple RUNSTATS commands with the SAMPLED 
DETAILED index option concurrently, you might observe a server 
abend, or inaccurate index statistics. 
 
This problem can occur only with the SAMPLED DETAILED index 
option.  In DB2 V10.1, when the DETAILED index option is 
indicated without explicit specification of SAMPLED or 
UNSAMPLED, SAMPLED is the default.  RUNSTATS with the UNSAMPLED 
DETAILED index option does not observe the problem.  RUNSTATS 
where the DETAILED index option is not specified does not 
observe the problem. 
 
Concurrent runstats executions can be common in environments 
where real time statistics (AUTO_STMT_STATS) is enabled.  In 
environments where AUTO_RUNSTATS is enabled, and AUTO_STMT_STATS 
is disabled, only one automatic runstats can be executing at any 
given point in time.  Unless otherwise directed by statistics 
profiles, automatic runstats uses the SAMPLED DETAILED index 
option when collecting statistics.  As such, environments 
enabled for real time statistics is vulnerable to this problem. 
 
While real times statistics is used prevalently in DB2 10 
customer environments, to date, the server abend symptom has 
been reported only in one installation.  The installation was a 
zLinux server, but other platforms are vulnerable as well. 
 
When the abend symptom occurs, the stack trace for the failing 
EDU might look like this: 
 
sqloEDUCodeTrapHandler 
sqldHashZValue32 
sqlis_touch_page 
sqliProcessColStats 
sqlischs 
sqlistat 
sqldIndexStats 
sqlrLocalRunstats 
 
When the inaccurate statistics symptom occurs, the inaccuracy is 
likely to suggest that an index is less clustered than it is. 
This inaccuracy can affect the query optimizer. 
 
Aside from automatic statistics collections performed by DB2, 
runstats activity can occur from user actions: 
- RUNSTATS command, or db2Runstats API 
- CREATE INDEX with statistics collection 
- CREATE INDEX, when registry variable 
DB2_CREATE_INDEX_COLLECT_STATS is set 
- LOAD with statistics collection 
- REDISTRIBUTE with statistics collection 
- REORGCK with update statistics 
 
You can check in-progress runstats executions using the LIST 
UTILITIES command.

**************************************************************** 
* USERS AFFECTED:                                              * 
* All users                                                    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 version 10.5.0.3.                             * 
****************************************************************

Disable AUTO_STMT_STATS if enabled.  Avoid user runstats 
activity that can lead to multiple concurrent RUNSTATS with the 
SAMPLED DETAILED index option. 
 
 
- disable automatic runstats, by setting AUTO_RUNSTATS (or one 
of its parents AUTO_TBL_MAINT or AUTO_MAINT) to off 
- do not use the SAMPLED keyword on the "index statistics 
clause" 
- do not execute runstats command concurrently 
- do not invoke runstats via other means (reorgchk, create 
index, load, redistribute)

DB2 Version 10.5 Fix Pack 3 for Linux, UNIX, and Windows
 DB2 Version 10.5 Fix Pack 3a for Linux, UNIX, and Windows
 DB2 Cancun Release 10.5.0.4 (also known as Fix Pack 4) for Linux, UNIX, and Windows
 DB2 Version 10.5 Fix Pack 9 for Linux, UNIX, and Windows
 

The problem is first fixed in DB2 version 10.5.0.3.

keiner bekannt / siehe Local-Fix

Datum - Problem gemeldet    :
Datum - Problem geschlossen :
Datum - der letzten Änderung:

29.07.2013
02.12.2013
02.12.2013