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Problem IT31677
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Status: Closed |
A symptom is high latch wait times on SQLO_LT_sqeLocalDatabase__dblatch causing slow connections in automated HADR.
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| product: |
DB2 FOR LUW / DB2FORLUW / B10 - DB2 |
| Problem description: |
As of v111m4fp5, connections may be slower in an automated HADR
environment compared to the same environment on a previous
fixpack. A symptom is high latch wait times on
SQLO_LT_sqeLocalDatabase__dblatch reported in
MON_GET_EXTENDED_LATCH_WAIT and waiters on that latch in "db2pd
-latches" output when new connections are being opened.
Backtraces from Db2 engine (db2sysc) collected during the issue
with "db2pd -stack all" or OS tools ("gstack" on Linux,
"procstack" on AIX) will show the thread holding
SQLO_LT_sqeLocalDatabase__dblatch latch with
sqlhaSetupHAInfrastructure function near the top of the stack,
e.g.:
read
sqloReadNamedPipe
sqloInitializeVendorProcess
sqlhaSetupHAInfrastructure
sqlhaIsHADRAutomationEnabled
hdrCheckDb
sqeLocalDatabase::SubsequentConnect
sqeDBMgr::StartUsingLocalDatabase
sqeApplication::AppStartUsing
sqleProcessConnectType
whilst thread waiting on the latch will wait in
sqeDBMgr::StartUsingLocalDatabase->sqloSpinLockConflict, e.g.:
sqloSpinLockConflict
sqeDBMgr::StartUsingLocalDatabase
sqeApplication::AppStartUsing
sqleProcessConnectType
sqeApplication::AppLocalStart
sqlelostWrp
sqleUCengnInit
sqleUCagentConnect
Example Holder Stack:
*** Stack ***
Timestamp: 1579190584.884346000
0x00007F14503B2566
_Z25ossDumpStackTraceInternalmR11OSSTrapFileiP7siginfoPvmm +
0x0356
0x00007F14503B21AB ossDumpStackTraceV98 + 0x002b
0x00007F14503AE397 _ZN11OSSTrapFile6dumpExEmiP7siginfoPvm +
0x00d7
0x00007F1457C36497 sqlo_trce + 0x03c7
0x00007F1457DA7F5B sqloDumpDiagInfoHandler + 0x020b
0x00007F145F998630 address: 0x00007F145F998630 ; dladdress:
0x00007F145F989000 ; offset in lib: 0x000000000000F630 ;
0x00007F145F99775B read + 0x002b
0x00007F1457C6AA71 sqloReadNamedPipe + 0x0211
0x00007F1457C2F0FF sqloInitializeVendorProcess + 0x0e5f
0x00007F14520309D2 address: 0x00007F14520309D2 ; dladdress:
0x00007F145090C000 ; offset in lib: 0x00000000017249D2 ;
0x00007F1451FEDBDD
_Z26sqlhaSetupHAInfrastructurePP18SQLO_VENDOR_HANDLEPPciP27sqlha
OpenDomainHandleStructPij + 0x01ad
0x00007F145204CC61 _Z28sqlhaIsHADRAutomationEnabledPKcPb +
0x0391
0x00007F1451F5BE2A
_Z10hdrCheckDbP16sqeLocalDatabaseP8sqeAgentP5sqlca + 0x0aaa
0x00007F145607FF4B
_ZN16sqeLocalDatabase17SubsequentConnectEP8SQLE_BWAP8sqeAgenthPi
P8sqlo_gmti + 0x0b2b
0x00007F1456046DDF
_ZN8sqeDBMgr23StartUsingLocalDatabaseEP8SQLE_BWAP8sqeAgentRccP8s
qlo_gmtPb + 0x144f
0x00007F1455F6E2DE
_ZN14sqeApplication13AppStartUsingEP8SQLE_BWAP8sqeAgentccP5sqlca
Pc + 0x044e
0x00007F1455F8144C
_Z22sqleProcessConnectTypeP14db2UCinterfaceP8SQLE_BWAP8sqeAgentP
5sqlcaP22SQLELOST_STATUS_VECTOR + 0x00ac
0x00007F1455F6C970
_ZN14sqeApplication13AppLocalStartEP14db2UCinterface + 0x07b0
Example Waiter Stack
Stack:
======================
0x00007F14503B2566
_Z25ossDumpStackTraceInternalmR11OSSTrapFileiP7siginfoPvmm +
0x0356
0x00007F14503B21AB ossDumpStackTraceV98 + 0x002b
0x00007F14503AE397 _ZN11OSSTrapFile6dumpExEmiP7siginfoPvm +
0x00d7
0x00007F1457C36497 sqlo_trce + 0x03c7
0x00007F1457DA7F5B sqloDumpDiagInfoHandler + 0x020b
0x00007F145F998630 address: 0x00007F145F998630 ; dladdress:
0x00007F145F989000 ; offset in lib: 0x000000000000F630 ;
0x00007F145F997E9D __nanosleep + 0x002d
0x00007F1457C3145F sqloSpinLockConflict + 0x05cf
0x00007F145604BEC4 address: 0x00007F145604BEC4 ; dladdress:
0x00007F145090C000 ; offset in lib: 0x000000000573FEC4 ;
0x00007F1456046C65
_ZN8sqeDBMgr23StartUsingLocalDatabaseEP8SQLE_BWAP8sqeAgentRccP8s
qlo_gmtPb + 0x12d5
0x00007F1455F6E2DE
_ZN14sqeApplication13AppStartUsingEP8SQLE_BWAP8sqeAgentccP5sqlca
Pc + 0x044e
0x00007F1455F8144C
_Z22sqleProcessConnectTypeP14db2UCinterfaceP8SQLE_BWAP8sqeAgentP
5sqlcaP22SQLELOST_STATUS_VECTOR + 0x00ac
0x00007F1455F6C970
_ZN14sqeApplication13AppLocalStartEP14db2UCinterface + 0x07b0
0x00007F145630B26F _Z11sqlelostWrpP14db2UCinterface + 0x004f
0x00007F1456311121 _Z14sqleUCengnInitP14db2UCinterfacet +
0x0891
0x00007F145630777C sqleUCagentConnect + 0x089c
0x00007F14565AE06D
_Z18sqljsConnectAttachP13sqljsDrdaAsCbP14db2UCinterface + 0x02ed
0x00007F145653DBFB
_Z16sqljs_ddm_accsecP14db2UCinterfaceP13sqljDDMObject + 0x008b
0x00007F1456531DBD
_Z17sqljsParseConnectP13sqljsDrdaAsCbP13sqljDDMObjectP14db2UCint
erface + 0x01ed
0x00007F1456532FDE
_Z10sqljsParseP13sqljsDrdaAsCbP14db2UCinterfaceP8sqeAgentb +
0x054e
0x00007F1456525EBD address: 0x00007F1456525EBD ; dladdress:
0x00007F145090C000 ; offset in lib: 0x0000000005C19EBD ;
0x00007F145652C4A3 address: 0x00007F145652C4A3 ; dladdress:
0x00007F145090C000 ; offset in lib: 0x0000000005C204A3 ;
0x00007F145652D15F _Z17sqljsDrdaAsDriverP18SQLCC_INITSTRUCT_T
+ 0x011f
0x00007F1455F53CE3 _ZN8sqeAgent6RunEDUEv + 0x0de3
0x00007F145988463E _ZN9sqzEDUObj9EDUDriverEv + 0x01be
0x00007F1457DA5A0A sqloEDUEntry + 0x057a
0x00007F145F990EA5 address: 0x00007F145F990EA5 ; dladdress:
0x00007F145F989000 ; offset in lib: 0x0000000000007EA5 ;
0x00007F144F3B68CD clone + 0x006d |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Automated HADR environments *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Request special build if affected. *
**************************************************************** |
| Local Fix: |
No local fix available |
| Solution |
|
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 28.01.2020
03.04.2020
03.04.2020 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
