DB2 - Problembeschreibung
| Problem IC70922 | Status: Geschlossen |
A RANGE JOIN PREDICATE JOINED TO A UNION ALL VIEW WITH A GROUP B Y CLAUSE MAY PRODUCE A SUB-OPTIMAL PLAN. | |
| Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
| Problembeschreibung: | |
Db2 may not push down a range join to a Union All view into the
tables of the Union All view.This would prevent Db2 to produce
a sub-optimal plan.
.
The following conditions must be met in order to hit this proble
m:
.
1) There is a Group By clause on the table and the Union
All view of the range join predicate.
2) Any column from the table in the range join predicate
derives from an expression that is not a column.
.
For example:
.
create table br1(tranid integer, trandate date, amount decimal);
create table br2(tranid integer, trandate date, amount decimal);
create view ua as (select * from br1 union all select * from
br2);
.
create table datedim(durid integer, startdate date, enddate
date);
.
create view vdatedim(durid, startdate, enddate)
as
(select durid,
case when month(startdate) = 3 then startdate + 1 day
else startdate end startdate,
enddate
from datedim
);
.
select ua.trandate, count(tranid), sum(amount)
from ua, vdatedim
where ua.trandate between vdatedim.startdate and
vdatedim.enddate
group by ua.trandate
;
. | |
| Problem-Zusammenfassung: | |
Db2 may not push down a range join to a Union All view into the
tables of the Union All view.This would prevent Db2 to produce
a sub-optimal plan.
.
The following conditions must be met in order to hit this
proble
m:
.
1) There is a Group By clause on the table and the Union
All view of the range join predicate.
2) Any column from the table in the range join predicate
derives from an expression that is not a column.
.
For example:
.
create table br1(tranid integer, trandate date, amount
decimal);
create table br2(tranid integer, trandate date, amount
decimal);
create view ua as (select * from br1 union all select * from
br2);
.
create table datedim(durid integer, startdate date, enddate
date);
.
create view vdatedim(durid, startdate, enddate)
as
(select durid,
case when month(startdate) = 3 then startdate + 1
day
else startdate end startdate,
enddate
from datedim
);
.
select ua.trandate, count(tranid), sum(amount)
from ua, vdatedim
where ua.trandate between vdatedim.startdate and
vdatedim.enddate
group by ua.trandate
;
. | |
| Local-Fix: | |
| verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows | |
| Lösung | |
fixed >= v97 fpk4 | |
| Workaround | |
keiner bekannt / siehe Local-Fix | |
| Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 02.09.2010 29.04.2011 29.04.2011 |
| Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FPk4 | |
| Problem behoben lt. FixList in der Version | |
| 9.7.0.4 |
|