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Problem IC90770
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Status: Closed |
ZIGZAG JOIN WITH QUERY DEGREE > 1 MAY HANG OR FAIL WHEN A SUBAGENT EXITS EARLY WITH NO ROWS FOUND IN DIMENSION PROCESSING |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
A ZIG ZAG JOIN executed with multiple subagents can hang or
fail, when some of the subagents exit early with no row found
error during dimension processing. Subagents, which do not exit
early, will hang in the following stacktrace:
0x09000000000EDF78 thread_wait + 0x98
0x09000000561181D0 sqloWaitEDUWaitPost + 0x254
0x0900000059804E18
IntrptWaitLock__19@52@276650@sqeAgentFP16SQLO_EDUWAITPOSTiPUiT2
+ 0x538
0x0900000056734D9C sqlrittb__FP8sqlrr_cb + 0x530
0x09000000589928C0 sqlriZZOpenDims__FP8sqlrr_cbP10sqlri_zzob +
0x7FC
0x090000005898EA98 sqlriZZInit__FP8sqlrr_cbP10sqlri_zzob + 0x8C
0x090000005898E198 sqlriZigZagJoin__FP8sqlrr_cb + 0xD8
0x090000005609A268 sqlriSectInvoke__FP8sqlrr_cbP12sqlri_opparm +
0x30
0x0900000054AB6B20 sqlrr_smp_router__FP8sqlrr_cb + 0x738
0x090000005458D748
sqlrr_subagent_router__FP8sqeAgentP12SQLE_DB2RA_T + 0x864
0x090000005458C1C8 @82@sqleSubRequestRouter__FP8sqeAgentPUiPUl +
0x3B4
0x09000000545850B8 sqleProcessSubRequest__FP8sqeAgent + 0x48C
0x0900000055D4BF8C RunEDU__8sqeAgentFv + 0x6A0
0x0900000055D4797C EDUDriver__9sqzEDUObjFv + 0x13C
0x0900000055D47804 sqlzRunEDU__FPcUi + 0x10
0x0900000055D5864C sqloEDUEntry + 0x264
The hang as described above is the most likely symptom of this
problem, however given that the root cause of this problem is an
smp agent prematurely exiting the runtime execution, there may
be other possible effects as well, depending on the nature of
the access plan, such as hangs in other codepaths, sql0901
errors or other unexpected behaviour.
The coordinator agent will wait on the table queue with this
stacktrace, when subagents exit early:
0x09000000000EDF78 thread_wait + 0x98
0x09000000561181D0 sqloWaitEDUWaitPost + 0x254
0x09000000565F37C4 WaitRecvReady__11sqkfChannelFiT1 + 0x230
0x09000000573A0620
ReceiveAnyBuffer__11sqkfChannelFPP10sqkfBufferiPi + 0x660
0x090000005739F4F8
sqlkqrcv__FP8SQLKQ_CBP8sqeAgentPiPP10sqkfBufferT3 + 0x4A4
0x090000005739ECE4 sqlktrcv__FP9sqlri_taoPi + 0xB0
0x090000005739D308
sqlkt_unpack_tuple__FP9sqlri_taoPiPbP5sqlcaPUiPUlP8sqeAgent +
0x648
0x09000000573A2C20 sqlktftc__FP8sqeAgentP9sqlri_taoP5sqlcaPUiPUl
+ 0x6DC
0x0900000057396D30 sqlritqa__FP8sqlrr_cb + 0x238
0x090000005609A268 sqlriSectInvoke__FP8sqlrr_cbP12sqlri_opparm +
0x30
0x09000000560382AC
sqlrr_process_fetch_request__FP14db2UCinterface + 0x18C
0x0900000055FA3554
sqlrr_open__FP14db2UCinterfaceP15db2UCCursorInfo + 0x99C
0x0900000055FA1D98
sqljs_ddm_opnqry__FP14db2UCinterfaceP13sqljDDMObject + 0x1D74
0x0900000055FD4138
sqljsParseRdbAccessed__FP13sqljsDrdaAsCbP13sqljDDMObjectP14db2UC
interface + 0x1C4
... |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 10.1 Fix Pack 3. *
**************************************************************** |
| Local Fix: |
There are several ways to overcome the situation:
* set QUERY DEGREE to 1 for the SQL statement in question
* set INTRA_PARALLEL to NO in the DBM CFG
* db2set DB2_REDUCED_OPTIMIZATION="ZZJN OFF" |
| available fix packs: |
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
First fixed in DB2 Version 10.1 Fix Pack 3. |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC95440
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 12.03.2013
02.10.2013
02.10.2013 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.3
|
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| 10.1.0.3
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