|
Problem IC94323
|
Status: Closed |
LATCH PROTOCOL ISSUE IN ZIG ZAG JOIN EXECUTION LEADING TO DEADLATCH BETWEEN SUBAGENTS |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
This problem is similar to apar IC91168.
The problem will manifest itself as 2 subagents for one
statement deadlatching themselves on 2 internal latches.
This can easily be identified by running db2pd -latches which
may show :
db2pd -latches shows :
Latches:
Address Holder Waiter Filename
LOC LatchType HoldCount
0x0700000030CD7BD8 20049 20563 sqlpsvpt.C
207 SQLO_LT_SQLP_SAVEPOINTS__spLatch 1
0x07000000201F0128 20563 20049
/view/db2_v101fp2_aix64_s121127_special_30486/vbs/engn/include/s
qldinlines.h 8574 SQLO_LT_SQLD_APP_CB__inDMSlatch 1
The names of the latches : SQLO_LT_SQLP_SAVEPOINTS__spLatch and
SQLO_LT_SQLD_APP_CB__inDMSlatch are important here
and you will see that the holder and waiter are reversed for the
2 latches.
Collecting stack information via db2pd -stack all will show
these 2 subagents with the following stacks:
Subagent 1 is in sqldRowInsert requesting the inDMS latch,
holding the SavePoint latch.
getConflictComplex
getConflict
sqldRowInsert
sqlrinsr
sqlriisr
sqlriSectInvoke
Subagent 2 is in sqldBeginIndexCreate requesting the SavePoint
latch, holding the inDMS latch.
sqlpGetSPLatch
sqlpSpReq
sqldBeginIndexCreate
sqlriCreateTempTableIndex
sqlriCreateIndexedTempTable
sqlritib2
sqldDataFetch
sqliScanLeaf2NoLocking
sqlifnxt
sqlirdk
sqldIndexFetch
sqldRowFetch
sqlritaSimplePerm
sqlriZZOpenDims
sqlriZZInit
sqlriZigZagJoin |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* all *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade the database server to V10.1 Fix Pack 4 *
**************************************************************** |
| Local Fix: |
To avoid this problem, the usage of the Zig Zag join , join
strategy can be disabled by running :
db2set DB2_REDUCED_OPTIMIZATION="ZZJN OFF" |
| available fix packs: |
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
This problem has first been fixed in V10.1 Fix Pack 4 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC98144
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 23.07.2013
26.06.2014
26.06.2014 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.4
|
 |
