|
Problem IC66252
|
Status: Closed |
DB2 INSTANCE ENDS ABNORMALLY COMPILING QUERY WITH A LARGE NUMBER OF UNIONS |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
Compiling a query with a large number of UNIONs may result in a
stack overflow and termination of the DB2 instance. The call
stack looks similar to this example from Linux:
0000002A97833854 _Z24sqlnq_process_connect_byP9sqlnq_qtbP3loc
+ 0x001c
(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.glibc.2.
3/lib64/libdb2e.so.1)
0000002A97835D77 _Z24sqlnq_process_connect_byP9sqlnq_qtbP3loc
+ 0x253f
(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.glibc.2.
3/lib64/libdb2e.so.1)
0000002A97835D77 _Z24sqlnq_process_connect_byP9sqlnq_qtbP3loc
+ 0x253f
(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.glibc.2.
3/lib64/libdb2e.so.1)
0000002A97835D77 _Z24sqlnq_process_connect_byP9sqlnq_qtbP3loc
+ 0x253f
(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.glibc.2.
3/lib64/libdb2e.so.1)
...
For this problem to occur, the DB2_COMPATIBILITY_VECTOR registry
variable must have the hierarchical query bit set (bit 4), e.g.:
DB2_COMPATIBILITY_VECTOR=08
or
DB2_COMPATIBILITY_VECTOR=ORA
But the query does not necessarily have to use hierarchical
queries (i.e. a CONNECT BY clause). |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* Compiling a query with a large number of UNIONs may resultin *
* astack overflow and termination of the DB2 instance. *
* Thecallstack looks similar to this example from *
* Linux:0000002A97833854_Z24sqlnq_process_connect_byP9sqlnq_qtbP
* 0x001c(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.
* 0x253f(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.
* 0x253f(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.
* 0x253f(/ms/dist/ibmdb2/PROJ/ds/9.5.4.4/.exec/x86_64.linux.2.6.
* this problem to occur, the *
* DB2_COMPATIBILITY_VECTORregistryvariable must have the *
* hierarchical query bit set (bit *
* 4),e.g.:DB2_COMPATIBILITY_VECTOR=08orDB2_COMPATIBILITY_VECTOR=
* the query does not necessarily have to use *
* hierarchicalqueries (i.e. a CONNECT BY clause). *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 v9.5 Fix Pack 6Otherwise, disable *
* hierarchical queries if not needed byunsetting bit 4 *
* inDB2_COMPATIBILITY_VECTOR. Alternatively, rewrite the *
* querytoreduce the number of UNIONs. *
**************************************************************** |
| Local Fix: |
Disable hierarchical queries if not needed by unsetting bit 4 in
DB2_COMPATIBILITY_VECTOR. Alternatively, rewrite the query to
reduce the number of UNIONs. |
| available fix packs: |
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
First fixed in DB2 v9.5 Fix Pack 6 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC66378 IC66653
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 11.02.2010
25.05.2010
25.05.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP6,
9.5.FP6Other
|
| Problem solved according to the fixlist(s) of the following version(s) |
