DB2 FOR LUW / DB2FORLUW / 970 - DB2

XML performance may degrade due to latch contention on the 
SMemPool latch.  This APAR makes a change to avoid this 
latching.  The below information is indicative of what may be 
seen in the data collection to help identify if this latch 
contention is the cause of the problem. 
 
The following entries in the perfcount output show higher than 
expected data: 
7840115    (17444 sec, 586829044 nanosec)     sqlmoAllocBlock 
8811909    (17441 sec, 562578302 nanosec)     sqlogmblkEx 
8807940    (16167 sec, 858052623 nanosec)     sqlofmblkEx 
679951        (33779 sec, 978299318 nanosec) 
sqldFullFormatFixedVar 
676169        (33807 sec, 367006949 nanosec)     sqldRowUpdate 
170503        (33782 sec, 631696253 nanosec) 
sqldFormatXDADesc 
352868        (33584 sec, 655165531 nanosec) 
sqlo_xlatch::getConflict 
 
 
The latch information in the stacks show two latches held, and 
297 waiters for the SMemPool latch: 
 
4743220.185043.000.stack.txt:Holding Latch type: 
(SQLO_LT_SMemPool__MemLatchType__latch) - Address: 
(7000001a00003e0), Line: 45, File: 
/view/db2_v97fp2_aix64_s100514/vbs/engn/include/sqlo_mem_latch.h 
HoldCount: 1 
4743220.197894.000.stack.txt:Holding Latch type: 
(SQLO_LT_sqlmon_conn__rds_latch) - Address: (7000000e003cd38), 
Line: 687, File: sqlmacb.C HoldCount: 1 
 
$ cat * | grep -c "Waiting on latch type: 
(SQLO_LT_SMemPool__MemLatchType__latch)" 
297 
 
The stack for the holder of SMemPool latch may look as follows: 
<StackTrace> 
-------Frame------ ------Function + Offset------ 
0x0900000006B1E15C sqloSpinLockReleaseConflict + 0x9C 
0x0900000006B1E37C sqloSpinLockReleaseConflict@glue74 + 0x78 
0x0900000006B1E2BC releaseLatch__12SMemBasePoolFv + 0xC 
0x0900000006B2563C sqlogmblkEx + 0xB8 
0x0900000006B24E20 sqlogmblkEx + 0x25C 
Stack traceback unavailable. 
</StackTrace>

**************************************************************** 
* USERS AFFECTED:                                              * 
* all users                                                    * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See APAR description                                         * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Users should upgrade to V97 fp4                              * 
****************************************************************

DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
 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
 

With this APAR fix, users will not see latch contention on the 
SMemPool latch.

keiner bekannt / siehe Local-Fix

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

27.09.2010
19.07.2011
19.07.2011

9.7.FP4