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Re: automated index suggestor -- request for comment

From: Hannu Krosing <hannu(at)tm(dot)ee>
To: gry(at)ll(dot)mit(dot)edu
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: automated index suggestor -- request for comment
Date: 2002-12-13 17:00:32
Message-ID: 1039798832.19813.28.camel@huli (view raw or flat)
Thread:
Lists: pgsql-performance
I cc'b back to list, hope this is ok?

On Fri, 2002-12-13 at 14:56, george young wrote:
> On 13 Dec 2002 12:05:36 +0000
> Hannu Krosing <hannu(at)tm(dot)ee> wrote:
> 
> > On Fri, 2002-12-13 at 03:22, johnnnnnn wrote:
> > 
> > In worst case you could generate the entries in pg_class table without
> > building the actual index and then drop or rollback when the explain is
> > ready.
> > 
> --> Of course you could just determine all possibly useful indexes and <--
> --> generate then anyhow an then drop them if they were not used ;)    <--
> 
> Why not!  At least for selects, this seems like the ideal.  For insert
> and update, you have to deal with updating the superfluous indexes --
> does the planner include index updating in its work estimates? 

Probably not -  the work should be almost the same (modulo cached status
of index pages) for any plan. 

At least I think we don't optimize the plan for different index access
patterns for updating indexes.

> > For queries
> that use functions in the where clause, you'd have to parse enough to know
> to include indexes on the functions (I know-- the last time I said "all I
> have to do is parse ..." I was really sorry later...).
-- 
Hannu Krosing <hannu(at)tm(dot)ee>

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