|
Problem IT21083
|
Status: Closed |
POOR PERFORMANCE WHEN FORCE_REPLICATED_MQT_MERGE IS SET |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
DB2 may show poor performance when following conditions are met:
- Registry variable FORCE_REPLICATED_MQT_MERGE is set
- There are replicated MQTs that can be matched
- There is EXIST/IN subquery and/or  SELECT DISTINCT
- There are joins on multiple tables or joins |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Db2 10.5 Fix Pack 9 or higher *
**************************************************************** |
| Local Fix: |
1) Unset registry FORCE_REPLICATED_MQT_MERGE
or
2) Using registry setting DB2COMOPT=NO_DEEPKEYPU
or
2) If the query has EXIST/IN subquery, rewrite the query to
convert the EXIST/IN into join. |
| Solution |
First fixed in Db2 10.5 Fix Pack 9 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 19.06.2017
29.09.2017
29.09.2017 |
| Problem solved at the following versions (IBM BugInfos) |
9.0.
|
| Problem solved according to the fixlist(s) of the following version(s) |
