|
Problem IC77537
|
Status: Closed |
IMPROVE THE HANDLING OF CONVERSION TO NLJOIN FROM MULTIPLE IN PREDICATES |
| product: |
DB2 FOR LUW / DB2FORLUW / 980 - DB2 |
| Problem description: |
If a query WHERE clause contains more than one simple IN
predicates whose IN operand is base column and IN elements are
composed of only literals, DB2 query compiler can convert one of
them to NLJOIN. It is possible that the compiler converts a
suboptimal IN predicate rather than the optimal one. The fix
makes sure the converted IN predicate is the optimal one.
Local fix: Use optimizer profile option "<INLIST2JOIN
OPTION="ENABLE" TABLE="TABLE_NAME" COLUMN="COLUMN_NAME"/>.
Replace TABLE_NAME and COLUMN_NAME with the real name of the IN
predicate dedicated to DB2 compiler for attempting the IN to
NLJOIN conversion. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All users *
****************************************************************
* PROBLEM DESCRIPTION: *
* If a query WHERE clause contains more than one simple IN *
* *
* predicates whose IN operand is base column and IN elements *
* are *
* composed of only literals, DB2 query compiler can convert *
* one of *
* them to NLJOIN. It is possible that the compiler converts a *
* *
* suboptimal IN predicate rather than the optimal one. The fix *
* *
* makes sure the converted IN predicate is the optimal one. *
* *
* *
* *
* Local fix: Use optimizer profile option "<INLIST2JOIN *
* *
* OPTION="ENABLE" TABLE="TABLE_NAME" COLUMN="COLUMN_NAME"/>. *
* *
* Replace TABLE_NAME and COLUMN_NAME with the real name of the *
* IN *
* predicate dedicated to DB2 compiler for attempting the IN to *
* *
* NLJOIN conversion. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to latest fix pack. *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 9.8 Fix Pack 4 for AIX and Linux
DB2 Version 9.8 Fix Pack 5 for AIX and Linux
|
| Solution |
|
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 15.07.2011
09.08.2011
09.08.2011 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.8.0.4
|
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