|
Problem IC78830
|
Status: Closed |
CRASH OR WRONG RESULT FOR QUERY CONTAINING LONG STRING IN PREDICATE "LIKE" IN A MIXED/EUC CODEPAGE. |
| product: |
DB2 FOR LUW / DB2FORLUW / 910 - DB2 |
| Problem description: |
If the following conditions are met:
1) A query contains a "like" comparison, where the pattern to
compare has prefixed characters followed by wildcard such as
this example:
select columns from table where pattern like "abc%"
2) The data is in a mixed or EUC codepage
3) The pattern "abc%" has a length that is greater than the
column data that is being scanned.
Then there exists the possibility that the comparison may do an
invalid memory access that will crash the instance. In very tiny
opportunity, a wrong result might return.
If a stack traceback is generated, the function at the top of
the stack will be an OS memory compare function (differs
depending on platform, eg. intel_fast_memcmp on Intel platform)
with sqlv_mixd_short_search() below it. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* If the following conditions are met: *
* *
* 1) A query contains a "like" comparison, where the pattern *
* to compare has prefixed characters followed by wildcard such *
* as this example: *
* select columns from table where pattern like "abc%" *
* *
* 2) The data is in a mixed or EUC codepage *
* *
* 3) The pattern "abc%" has a length that is greater than the *
* column data that is being scanned. *
* *
* Then there exists the possibility that the comparison may do *
* an invalid memory access that will crash the instance. In *
* very tiny opportunity, a wrong result might return. *
* *
* If a stack traceback is generated, the function at the top *
* of the stack will be an OS memory compare function (differs *
* depending on platform, eg. intel_fast_memcmp on Intel *
* platform) with sqlv_mixd_short_search() below it. *
****************************************************************
* RECOMMENDATION: *
* Update to version 9.1 fixpack 11 or later fixpacks. *
**************************************************************** |
| Local Fix: |
Use shorter string in the LIKE predicate if it is possible. |
| available fix packs: |
DB2 Version 9.1 Fix Pack 11 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12 for Linux, UNIX and Windows
|
| Solution |
This problem is first fixed in version 9.1 fixpack 11. |
| Workaround |
Use shorter string in the LIKE predicate if it is possible. |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 20.09.2011
29.12.2011
29.12.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.1.FP11
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.1.0.11
|
 |
