RE: Using Views - Do they imfluence performance
My personal view is views are for end-users who need to see the 'raw' data,
but developers use the real tables.
-----Original Message-----
From: Art S. Kagel [mailto:kagel@bloomberg.net]
Sent: 10 March 1999 23:06
To: informix-list@iiug.org
Subject: Re: Using Views - Do they imfluence performance
FProse wrote:
>
> I'm Using v 7.3 on Aix 4.3. I've been asked to provice views that
represent some rather complex queries; 8 tables with
> outer joins. Will I see any performance imprevement in the use of a View
vs. straight execution of the query? I've
> tried to run both through dbaccess with EXPLAIN set on, and they return
identical estimated cost values. Other than
> making life easier for the programmers (and more diffficult for me) are
there any (positive or negative) benefits?
Views do not have a major impact on query performance one way or the
other normally. The exception is when you select a subset of the view
columns and/or join the view to another table. There are situations
where the optimizer cannot filter out the unneeded columns until the
query is completed and this can slow things down versus writing the
equivalent query against the underling tables.
Art S. Kagel