Re: Views

From: Michael Ho <infoage_at_hk.super.net>
Date: 1997/04/04
Message-ID: <3343DEBA.384F@hk.super.net>#1/1

Guy Harrison wrote:
>
> Ken,
>
> What might be happening is that the optimizer is using a unique index to
> perform the count(*) queries on table1 and table2. When you create a union
> view, the optimizer can't resolve this using just the indexes and so has
> to perform full table scans instead of full index scans. I did a quick
> test and this is what happens on my 7.2.3 system.
>

COUNT(*) don't use index, it use full access instead. Received on Fri Apr 04 1997 - 00:00:00 CST