Re: [PERFORM] A Better External Sort? - Mailing list pgsql-hackers

From Martijn van Oosterhout
Subject Re: [PERFORM] A Better External Sort?
Date
Msg-id 20051004122443.GF17589@svana.org
Whole thread Raw
In response to Re: [PERFORM] A Better External Sort?  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: [PERFORM] A Better External Sort?
List pgsql-hackers
On Tue, Oct 04, 2005 at 12:24:54PM +0100, Simon Riggs wrote:
> How did you determine the 1500 figure? Can you give some more info to
> surround that recommendation to allow everybody to evaluate it?

kleptog@vali:~/dl/cvs/pgsql-local/src/backend/utils/sort$ gcc -finline-limit-1000 -Winline -O2 -Wall
-Wmissing-prototypes-Wpointer-arith -Wendif-labels -fno-strict-aliasing -g -I../../../../src/include -D_GNU_SOURCE   -c
-otuplesort.o tuplesort.c 
tuplesort.c: In function 'applySortFunction':
tuplesort.c:1833: warning: inlining failed in call to 'inlineApplySortFunction'
tuplesort.c:1906: warning: called from here
tuplesort.c: In function 'comparetup_heap':
tuplesort.c:1833: warning: inlining failed in call to 'inlineApplySortFunction'
tuplesort.c:1937: warning: called from here
tuplesort.c: In function 'comparetup_index':
tuplesort.c:1833: warning: inlining failed in call to 'inlineApplySortFunction'
tuplesort.c:2048: warning: called from here
tuplesort.c: In function 'comparetup_datum':
tuplesort.c:1833: warning: inlining failed in call to 'inlineApplySortFunction'
tuplesort.c:2167: warning: called from here
kleptog@vali:~/dl/cvs/pgsql-local/src/backend/utils/sort$ gcc -finline-limit-1500 -Winline -O2 -Wall
-Wmissing-prototypes-Wpointer-arith -Wendif-labels -fno-strict-aliasing -g -I../../../../src/include -D_GNU_SOURCE   -c
-otuplesort.o tuplesort.c 
<no warnings>

A quick binary search puts the cutoff between 1200 and 1300. Given
version variation I picked a nice round number, 1500.

Ugh, that's for -O2, for -O3 and above it needs to be 4100 to work.
Maybe we should go for 5000 or so.

I'm using: gcc (GCC) 3.3.5 (Debian 1:3.3.5-13)

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.

pgsql-hackers by date:

Previous
From: Martijn van Oosterhout
Date:
Subject: Re: memory bug debugging
Next
From: "Dave Page"
Date:
Subject: Re: New Point Releases Available