|
Problem IC71502
|
Status: Closed |
XML PERFORMANCE MAY DEGRADE DUE TO LATCH CONTENTION |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
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> |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* all users *
****************************************************************
* PROBLEM DESCRIPTION: *
* See APAR description *
****************************************************************
* RECOMMENDATION: *
* Users should upgrade to V97 fp4 *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
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
|
| Solution |
With this APAR fix, users will not see latch contention on the
SMemPool latch. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 27.09.2010
19.07.2011
19.07.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP4
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.4
|
 |
