Re: Clock sweep not caching enough B-Tree leaf pages?

From: Andres Freund <andres(at)2ndquadrant(dot)com>
To: Peter Geoghegan <pg(at)heroku(dot)com>
Cc: Greg Stark <stark(at)mit(dot)edu>, Ants Aasma <ants(at)cybertec(dot)at>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Clock sweep not caching enough B-Tree leaf pages?
Date: 2014-04-17 20:39:20
Message-ID: 20140417203920.GB17874@awork2.anarazel.de
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On 2014-04-17 13:33:27 -0700, Peter Geoghegan wrote:
> Just over 99.6% of pages (leaving aside the meta page) in the big 10
> GB pgbench_accounts_pkey index are leaf pages.

That's a rather nice number. I knew it was big, but I'd have guessed
it'd be a percent lower.

Do you happen to have the same stat handy for a sensibly wide text or
numeric real world index? It'd be interesting to see what the worst case
there is.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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