Re: Abbreviated keys for Numeric (was: Re: B-Tree support function number 3 (strxfrm() optimization))

From: Peter Geoghegan <pg(at)heroku(dot)com>
To: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Cc: Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Abbreviated keys for Numeric (was: Re: B-Tree support function number 3 (strxfrm() optimization))
Date: 2015-02-20 23:14:16
Message-ID: CAM3SWZS-9VreaKQhrriYotYJW5LoERF_k2Le=tbEqc7-WKtyCg@mail.gmail.com
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On Fri, Feb 20, 2015 at 1:33 PM, Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> For example with the same percentile_disc() test as in the other thread:
>
> create table stuff as select random()::numeric as randnum
> from generate_series(1,1000000);
>
> analyze stuff;
>
> select percentile_disc(0) within group (order by randnum) from stuff;
>
>
> I get pretty much no difference in runtimes (not even for the smallest
> dataset, where the Datum patch speedup was significant).
>
> What am I doing wrong?

So you're testing both the patches (numeric + datum tuplesort) at the same time?

I can't think why this would make any difference. Did you forget to
initdb, so that the numeric sortsupport routine was used?

--
Peter Geoghegan

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