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Re: Re: Adding additional index causes 20,000x slowdown for certain select queries - postgres 9.0.3 - Mailing list pgsql-performance

From Claudio Freire
Subject Re: Re: Adding additional index causes 20,000x slowdown for certain select queries - postgres 9.0.3
Date
Msg-id AANLkTik3SfZih19i2svVX7BCxEOYkaGDGyzkovRrnZj3@mail.gmail.com
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In response to Re: Re: Adding additional index causes 20,000x slowdown for certain select queries - postgres 9.0.3  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
Responses Re: Re: Adding additional index causes 20,000x slowdown for certain select queries - postgres 9.0.3  ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>)
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On Wed, Mar 16, 2011 at 3:34 PM, Shaun Thomas <sthomas@peak6.com> wrote:
> If not, it seems like a valid configurable. We set our random_page_cost to
> 1.5 once the DB was backed by NVRAM. I could see that somehow influencing
> precedence of a backwards index scan. But even then, SSDs and their ilk
> react more like RAM than even a large RAID... so should there be a setting
> that passes such useful info to the planner?

Forgive the naive question...
but...

Aren't all index scans, forward or backward, random IO?

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