On Wed, 2009-05-20 at 23:01 -0400, Zdenek Kotala wrote:
We use default one. I did not tested difference between them, but IIRC
that Jignesh did some testing with umem. I will ask him. However if you
give me test scenario I can test it.
Talk with Dimitri from Sun who is doing scalability
On Tue, 2009-05-19 at 22:19 +0200, Zdenek Kotala wrote:
Chuck McDevitt píše v út 19. 05. 2009 v 09:33 -0700:
Solaris default malloc always uses sbrk(), and never ever tried to reduce
the sbrk point.
If you want a malloc that uses mmap, there is an non-default malloc that
does that
On Tue, 2009-05-19 at 16:49 -0400, Greg Stark wrote:
Well I'm just saying if you realloc a x kilobyte block into a 2x block
and the allocator can't expand it and has to copy then it seems
inevitable.
OK, understood.
So there is grounds at least for an investigation into how that works
On 05/20/2009 10:14 AM, Simon Riggs wrote:
On Tue, 2009-05-19 at 22:19 +0200, Zdenek Kotala wrote:
Chuck McDevitt píše v út 19. 05. 2009 v 09:33 -0700:
What I heart is that standard malloc is not good, but it is still here
for compatibility reason with old application which depends on some
So at least transiently we use 3x the size of the actual array.
I was conjecturing, prior to investigation. Are you saying you know
this/have seen this already?
Well I'm just saying if you realloc a x kilobyte block into a 2x block and
the allocator can't expand it and has to copy then it
Simon Riggs píše v st 20. 05. 2009 v 09:14 +0100:
What I heart is that standard malloc is not good, but it is still here
for compatibility reason with old application which depends on some
functionality.
Which one is used in the default PostgreSQL build for Solaris? If you
use
Just wanted to check some thoughts about how memory allocation works in
complex queries. Been thinking some more about recent Solaris testing
results that *seemed* to show issues with multiple concurrent queries
that have multiple sorts.
If we have a query that uses multiple sorts, we may have a
On Tue, May 19, 2009 at 12:32:13PM +0100, Simon Riggs wrote:
If we allocate large chunks of memory we use malloc(). So complex
queries can have multiple mallocs, followed by multiple reallocs. That
in itself seems likely to end up with roughly double memory use, since
realloc won't work
On Tue, 2009-05-19 at 09:17 -0400, Merlin Moncure wrote:
On Tue, May 19, 2009 at 7:44 AM, Martijn van Oosterhout
The threshold is dynamic apparently, but starts at 128KB.
I just read an article that suggests assuming that can be dangerous
(by one of the authors of jemalloc)...an
On Tue, May 19, 2009 at 12:32 PM, Simon Riggs si...@2ndquadrant.com wrote:
If we have a query that uses multiple sorts, we may have a top-level
sort, with child nodes that contain sorts also. In some cases we may
find with sub-nodes that have both inner and outer sub-trees that
contain sorts
On Tue, May 19, 2009 at 7:44 AM, Martijn van Oosterhout
klep...@svana.org wrote:
On Tue, May 19, 2009 at 12:32:13PM +0100, Simon Riggs wrote:
If we allocate large chunks of memory we use malloc(). So complex
queries can have multiple mallocs, followed by multiple reallocs. That
in itself seems
-Original Message-
From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers-
ow...@postgresql.org] On Behalf Of Simon Riggs
Sent: Tuesday, May 19, 2009 4:32 AM
To: pgsql-hackers
Subject: [HACKERS] Multiple sorts in a query
Just wanted to check some thoughts about how
On Tue, 2009-05-19 at 09:33 -0700, Chuck McDevitt wrote:
Is it possible that Solaris's default malloc isn't appropriate for
repeated use in complex queries that use multiple sorts?
http://developers.sun.com/solaris/articles/multiproc/multiproc.html
and recent OpenSolaris bug reports.
On Tue, 2009-05-19 at 13:52 +0100, Greg Stark wrote:
So at least transiently we use 3x the size of the actual array.
I was conjecturing, prior to investigation. Are you saying you know
this/have seen this already?
--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services
Well I'm just saying if you realloc a x kilobyte block into a 2x block
and the allocator can't expand it and has to copy then it seems
inevitable.
--
Greg
On 19 May 2009, at 14:11, Simon Riggs si...@2ndquadrant.com wrote:
On Tue, 2009-05-19 at 13:52 +0100, Greg Stark wrote:
So at
Chuck McDevitt píše v út 19. 05. 2009 v 09:33 -0700:
Solaris default malloc always uses sbrk(), and never ever tried to reduce the
sbrk point.
If you want a malloc that uses mmap, there is an non-default malloc that does
that (libumem or something?)
There are severals memory
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