From: Jeff Davis <pgsql@j-davis.com>
To: Andrew Lazarus <andrew@pillette.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: index structure for 114-dimension vector
Date: Fri, 20 Apr 2007 14:41:24 -0700
Message-ID: <1177105284.28383.31.camel@dogma.v10.wvs> (raw)
In-Reply-To: <1217328326.20070420120729@pillette.com>
References: <b42b73150704170917n33ebcdc8wc852a3fa02fd8bb5@mail.gmail.com>
<01db01c781e4$c700bf30$2e00a8c0@tridecap.com>
<b42b73150704181716wb1600aey8761b6793d3fd702@mail.gmail.com>
<1217328326.20070420120729@pillette.com>
On Fri, 2007-04-20 at 12:07 -0700, Andrew Lazarus wrote:
> I have a table with 2.5 million real[] arrays. (They are points in a
> time series.) Given a new array X, I'd like to find, say, the 25
> closest to X in some sense--for simplification, let's just say in the
> usual vector norm. Speed is critical here, and everything I have tried
> has been too slow.
>
> I imported the cube contrib package, and I tried creating an index on
> a cube of the last 6 elements, which are the most important. Then I
Have you tried just making normal indexes on each of the last 6 elements
and see if postgresql will use a BitmapAnd to combine them?
Regards,
Jeff Davis
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To: pgsql-performance@postgresql.org
Cc: pgsql@j-davis.com, andrew@pillette.com
Subject: Re: index structure for 114-dimension vector
In-Reply-To: <1177105284.28383.31.camel@dogma.v10.wvs>
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