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Problem IT30006
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Status: Closed |
DB2 MAY PRODUCE INCORRECT RESULTS FOR HSJN WITH PREDICATE THAT HAS CASE(COALESCE) AND NLJN OR ZZJOIN ON THE OUTER
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| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
DB2 MAY PRODUCE INCORRECT RESULTS FOR HSJN WHEN
- HSJN HAS COMPLEX PREDICATE THAT HAS CASE ( COALESCE )
- HSJN HAS NLJN OR ZZJOIN ON THE OUTER
- INTERNAL OPTIMIZATION IS APPLIED
Example of the Complex Predicate in HSJN from the Plan that
could produce wrong results:
Predicate Text:
--------------
(Q8.C1 =
CASE
WHEN (Q1.C2 = 'X')
THEN COALESCE(Q1.C3, 'Y')
WHEN NOT(Q1.C4 IN ('A', 'B'))
THEN
CASE
WHEN UPPER(COALESCE(Q2.C5, 'D')) IN ('E', 'F', 'G')
THEN 'H'
WHEN (UPPER(COALESCE(Q2.C5, 'D')) = 'K')
THEN 'L'
ELSE COALESCE(Q2.C5, 'D') END
ELSE COALESCE(Q2.C5, 'D') END)
Example of HSJN with NLJN on the outer:
101225
HSJN
( 6)
552757
/------/ ----
101225 46
NLJN ISCAN
( 7) (22)
552653 ...
/
101224 1
SCAN ISCAN
( 8) (21)
548163 ...
|
... |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Db2 10.5 Fix Pack 11 or higher *
**************************************************************** |
| Local Fix: |
db2set DB2_TCG_DEFAULT_OPTIONS="set disable_pushdown on"
instance restart is needed
Static packages need to be rebound. |
| Solution |
|
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : IT28638
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 15.08.2019
25.02.2020
25.02.2020 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
