Informix - Problem description
Problem IT17944 | Status: Closed |
SELECT FROM VIEW AND SUBQUERY RUNS MUCH SLOWER THAN A SELECT FROM THE UNDERLYING TABLES | |
product: | |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 | |
Problem description: | |
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 Summary: | |
**************************************************************** * 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: | |
Solution | |
Workaround | |
not known / see Local fix | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 14.11.2016 10.07.2017 10.07.2017 |
Problem solved at the following versions (IBM BugInfos) | |
12.10.xC9 | |
Problem solved according to the fixlist(s) of the following version(s) |