|
Problem IT17944
|
Status: Geschlossen |
SELECT FROM VIEW AND SUBQUERY RUNS MUCH SLOWER THAN A SELECT FROM THE UNDERLYING TABLES
|
| Produkt: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problembeschreibung: |
When selecting from views, the query running time can take about
15 times slower than selecting directly from the underlying
tables.
For example:
SELECT ...
FROM
SELECT ...
FROM ( View1
LEFT OUTERJOIN (
SELECT * FROM View2
INNER JOIN
SELECT * FROM View3
)
FULL OUTTER JOIN
SELECT ... FROM View2
The above query takes 34 mins 10 secs to return the result.
If this query uses underlying tables in the subquery instead of
views, it takes 2 minutes 35 seconds to run. |
| Problem-Zusammenfassung: |
****************************************************************
* USERS AFFECTED: *
* Users of 12.10.xC1 through 12.10.xC8. *
****************************************************************
* PROBLEM DESCRIPTION: *
* A query may have poor performance when Full-Outer-Join is *
* used, especially when one side of the FOJ is a very large *
* table. *
****************************************************************
* RECOMMENDATION: *
* Update to IBM Informix Server 12.10.xC9. *
**************************************************************** |
| Local-Fix: |
|
| Lösung |
|
| Workaround |
keiner bekannt / siehe Local-Fix |
| Weitere Daten |
Datum - Problem gemeldet :
Datum - Problem geschlossen :
Datum - der letzten Änderung:
| 14.11.2016
10.07.2017
10.07.2017 |
| Problem behoben ab folgender Versionen (IBM BugInfos) |
12.10.xC9
|
| Problem behoben lt. FixList in der Version |
