|
Problem IC66653
|
Status: Closed |
DB2 INSTANCE ENDS ABNORMALLY COMPILING QUERY WITH A LARGE NUMBER OF UNIONS |
| product: |
DB2 FOR LUW / DB2FORLUW / 980 - 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 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.
* 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.
* 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.
* 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.
* 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). *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 version 9.8 fix pack 3 *
**************************************************************** |
| 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 9.8 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.8 Fix Pack 4 for AIX and Linux
DB2 Version 9.8 Fix Pack 5 for AIX and Linux
|
| Solution |
First fixed in DB2 version 9.8 fix pack 3 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 24.02.2010
20.12.2010
20.12.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.8.FP3
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.8.0.3
|
 |
