Re: Indexes & Primary Keys (based on the same columns) - Mailing list pgsql-general

From Ow Mun Heng
Subject Re: Indexes & Primary Keys (based on the same columns)
Date
Msg-id 1193025227.1104.28.camel@neuromancer.home.net
Whole thread Raw
In response to Re: Indexes & Primary Keys (based on the same columns)  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-general
On Sun, 2007-10-21 at 20:49 -0700, Joshua D. Drake wrote:
> Ow Mun Heng wrote:
> > I'm wondering if what I'm doing is redundant.
> >
> > I have a primary key on columns (A,B,C,D)
> > and I've also defined an index based on the same columns (A,B,C,D)
> >
> > and sometimes in the query explain, I see the pkey being used for the
> > scan instead of the index.
> >
> > So.. That made me think perhaps the additional index on the _same_
> > parameter is redundant.
>
> A primary key creates an index so having a second index with the same
> definition is redundant.

Many thanks for the confirmation.

I'm dropping them...

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