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DB2 - Problem description

Problem IC87037 Status: Closed

DB2 MIGHT HANG WHILE COMPILING AN SQL STATEMENT ELIGIBLE FOR ZIGZAG JOIN
STRATEGY.

product:
DB2 FOR LUW / DB2FORLUW / A10 - DB2
Problem description:
In DB2 Version 10.1, the optimizer can consider the zigzag join 
strategy, and might choose it if the query satisfies the 
following criteria: 
- the fact table is joined with multiple dimension tables by 
equality predicates between each dimension table's primary key, 
unique index or unique constraint and the fact table columns; 
and 
- there is a suitable multicolumn index on the fact table that 
covers the above mentioned equality predicates between the fact 
table and at least two dimension tables. 
 
During query compilation, the DB2 server might hang if the 
optimizer chooses a zigzag join. 
The following stack trace can be observed if you encounter this 
problem: 
 
sqlno_compute_temp_index_stats 
sqlno_cost_iot_temp 
sqlno_cost_temp 
sqlno_prop_temp 
TEMP
Problem Summary:
**************************************************************** 
* USERS AFFECTED:                                              * 
* ALL                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.1 Fix Pack 3.                      * 
****************************************************************
Local Fix:
db2set DB2_REDUCED_OPTIMIZATION="ZZJN OFF, ZZJN_MULTI_FACT OFF" 
 
OR 
Use optimization level 0
available fix packs:
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows

Solution
First fixed in DB2 Version 10.1 Fix Pack 3.
Workaround
not known / see Local fix
Timestamps
Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :
05.10.2012
14.10.2013
14.10.2013
Problem solved at the following versions (IBM BugInfos)
Problem solved according to the fixlist(s) of the following version(s)
10.1.0.3 FixList
10.1.0.3 FixList