|
Problem IC66443
|
Status: Closed |
STATEMENT COMPILATION MAY FAIL TO USE THE STATISTICS COLLECTED FOR A GLOBAL TEMPORARY TABLE. |
| product: |
DB2 FOR LUW / DB2FORLUW / 980 - DB2 |
| Problem description: |
In some situations, statement compilation may fail to use the
statistics collected for a global temporary table. This may
lead to a non optimal access plan. For example, in the sequence
of:
1. declare global temporary table
2. insert data into the global temporary table
3. runstats on the global temporary
4. use the global temporary table in a query
the statement compilation in step4 may not use the statistics
collected in step3. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* In some situations, statement compilation may fail to use *
* the *
* statistics collected for a global temporary table. This may *
* *
* lead to a non optimal access plan. For example, in the *
* sequence *
* of: *
* *
* 1. declare global temporary table *
* *
* 2. insert data into the global temporary table *
* *
* 3. runstats on the global temporary *
* *
* 4. use the global temporary table in a query *
* *
* the statement compilation in step4 may not use the *
* statistics *
* collected in step3. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 UDB Version 9.8 FixPack 3 *
**************************************************************** |
| Local Fix: |
- After observing the problem, repeating the RUNSTATS operation
typically clears the problem.
- Querying the global temporary table prior to the RUNSTATS
operation, for example with "select 1 from session.t1 fetch
first 1 row only", typically avoids the problem. |
| 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 UDB Version 9.8 FixPack 3 |
| Workaround |
- After observing the problem, repeating the RUNSTATS operation
typically clears the problem.
- Querying the global temporary table prior to the RUNSTATS
operation, for example with "select 1 from session.t1 fetch
first 1 row only", typically avoids the problem. |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 18.02.2010
21.12.2010
21.12.2010 |
| 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
|
 |
