DB2 - Problem description
Problem IC81190 | Status: Closed |
DB2 LOGGER I/O CONTENTION CAUSING PERFORMANCE ISSUES | |
product: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problem description: | |
If LOGBUFSZ database configuration parameter is set to a high value, then contention can be seen during db2 logging since db2ReadLog API would be called repeatedly which can stress memory and cause performance issues on busy systems. db2pd -latches output will show db2 loggers waiting for the following latch: Latches: Address Holder Waiter Filename LOC LatchType No latch holders. 0x07000000700003E0 0 1135675 Unknown 45 SQLO_LT_SMemPool__MemLatchType__latch 0x07000000700003E0 0 1137474 Unknown 45 SQLO_LT_SMemPool__MemLatchType__latch 0x07000000700003E0 0 1138759 Unknown 45 0x0700000040027300 0 2316429 Unknown 189 SQLO_LT_SQLP_APPEND_LREC_CB_IO__logIOCompLatch 0x0700000040027300 0 102817 Unknown 189 SQLO_LT_SQLP_APPEND_LREC_CB_IO__logIOCompLatch The stack dumps for the db2logger process may look as follows: 0x09000000000EEEF8 thread_wait + 0x98 0x090000000DAB775C getConflictComplex__17SQLO_SLATCH_CAS64FCUl + 0x3DC 0x090000000DAB7ABC getConflict__17SQLO_SLATCH_CAS64FCUl + 0xC8 0x090000000DAB7BA0 getConflict__17SQLO_SLATCH_CAS64FCUl@glueF9 + 0x74 0x090000000DA00FCC sqlpProcessWakeUpList__FP9SQLP_DBCBP22SQLP_APPEND_LREC_CB_WA + 0x20 0x090000000DB3AA10 sqlpgasn2__FPcUi + 0x100 0x090000000DC8FBB8 sqloEDUEntry + 0x36C | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * All users on DB2 v97 FP5 and earlier * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 v97 FP6 * **************************************************************** | |
Local Fix: | |
As a temporary workaround, you may try reduce LOGBUFSZ a little and verify. The size has to be chosen carefully as too small value can cause performance impacts as well for a busy system. Hence, the value needs to be carefully chosen as per workloads on the system. | |
available fix packs: | |
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows | |
Solution | |
First Fixed in DB2 v97 FP6 | |
Workaround | |
not known / see Local fix | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 02.02.2012 26.06.2012 12.07.2012 |
Problem solved at the following versions (IBM BugInfos) | |
9.7.FP6 | |
Problem solved according to the fixlist(s) of the following version(s) | |
9.7.0.6 |