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Re: Why sequential scan when there's a supporting index?

From: "Joshua b(dot) Jore" <josh(at)greentechnologist(dot)org>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Why sequential scan when there's a supporting index?
Date: 2002-05-25 20:36:10
Message-ID: Pine.BSO.4.44.0205251535530.26775-100000@kitten.greentechnologist.org (view raw or flat)
Thread:
Lists: pgsql-novice
Sorry for being whiney. I'd still like to know where the gotchas are if
someone knows that.

Joshua b. Jore ; http://www.greentechnologist.org ; 10012 11010 11022
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---------- Forwarded message ----------
Date: Sat, 25 May 2002 11:57:39 -0500 (CDT)
From: Joshua b. Jore <josh(at)greentechnologist(dot)org>
Cc: PgSQL Novice ML <pgsql-novice(at)postgresql(dot)org>
Subject: Re: [NOVICE] Why sequential scan when there's a supporting index?

On 25 May 2002, Ron Johnson wrote:
> On Sat, 2002-05-25 at 03:52, Andrew McMillan wrote:
> > On Sat, 2002-05-25 at 02:25, Ron Johnson wrote:
> > For my personal view I'm OK with the current behaviour.  It has
> > tradeoffs, and this is one of the negatives, but although I find myself
> > doing this interactively quite often I only very rarely find myself
> > doing it inside an application.
>
> IMO, when a "proprietary" DBA (like me) hears that that statement
> does table scans, s/he will be stunned, and wonder what other
> "gotchas" are lurking out there awaiting someone who wants to
> query enterprise-sized tables.

I was wondering the same thing. I read the html manual, O'Reilly's
Practical PostgreSQL, Sam's PostgreSQL Developer's Handbook and have
browsed http://techdocs.postgresql.org. I also lurk on this list and
ocasionally ask and answer questions. Where in all that information am I
supposed to pick up that 'SELECT max(foo) FROM quux' should be written as
'SELECT foo FROM quux ORDER BY foo LIMIT 1'. That's really unintuitive and
if this info isn't in the docs I've read so far, I'm not sure where it is.
Am I supposed to read the source for comments as well? So mostly I just
want to know where these suggested work arounds are documented. Is there a
particular set of keywords that work for searching the hacker's list? I'm
at a loss as to where to get this (obviously) valuable info.

Pointers would be appreciated,




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Next:From: Sharon CowlingDate: 2002-05-25 23:38:00
Subject: Copy Comand question
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Subject: Re: Why sequential scan when there's a supporting index?

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