Subject: Re: AIX - Out of Memory
From: Brad Nicholson <bnichols@ca.afilias.info>
To: "Thorne, Francis" <thornef@cromwell.co.uk>
Cc: pgsql-admin@postgresql.org
In-Reply-To: 
 <81976671721DF04B9DCA6ECD87941A401E2CCE18@roundway.Cromwell-tools.co.uk>
References: 
 <81976671721DF04B9DCA6ECD87941A401E2CCE18@roundway.Cromwell-tools.co.uk>
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Date: Thu, 18 Feb 2010 13:01:39 -0500
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On Thu, 2010-02-18 at 08:46 +0000, Thorne, Francis wrote:
> Hi Brad,
> 
> Thanks for all your help with this, sorry for my ignorance on this.
> I've read through the F.A.O and found the section on setting MAXDATA but
> can only see the example of setting this to 0x00000000 for 32-bit.  I
> cant see any example of what I need to change this to if I wanted to run
> 64-bit, I don't suppose you have an idea what I would need to change
> this maxData figure to.


We've set ours to the upper limit of 2GB (0x80000000). Your usage may
vary.  You'll need to take into account the expected size of your
processes * the number of expected processes and make sure you have
enough RAM in the system to handle it.

> I assume using the LDEDIT command the maxData setting can be changed on
> the fly and we wont need to re-compile Postgres.

It can be, but I'm not sure exactly which components you will need to
touch.

We always build our binaries passing with this set higher, so I can't
comment on the effects of changing it on existing ones.

> Thanks again for all your help and patience !!
> 
> Fran
> 
> -----Original Message-----
> From: Brad Nicholson [mailto:bnichols@ca.afilias.info] 
> Sent: 16 February 2010 18:46
> To: Thorne, Francis
> Cc: pgsql-admin@postgresql.org
> Subject: RE: [ADMIN] AIX - Out of Memory
> 
> On Tue, 2010-02-16 at 16:44 +0000, Thorne, Francis wrote:
> > Please find details as requested, thanks again for you help
> > 
> >  /usr/local/pgsql837-64/bin/postgres:
> > 
> > 			***Object Module Header***
> > # Sections      Symbol Ptr      # Symbols       Opt Hdr Len     Flags
> >          4	0x005e247c	    46124	        120	0x9002
> > Flags=( EXEC DYNLOAD RWNONEXEC )
> > Timestamp = "06 Nov 12:55:11 2009"
> > Magic = 0x1f7  (64-bit XCOFF)
> 
> Your binary is 64-bit.
> 
> > 			***Optional Header***
> > Tsize        Dsize       Bsize       Tstart      Dstart
> > 0x003cc912  0x0005dde6  0x00073a38  0x100001f8  0x20000b0a
> > 
> > SNloader     SNentry     SNtext	     SNtoc       SNdata
> > 0x0004      0x0002      0x0001      0x0002      0x0002    
> > 
> > TXTalign     DATAalign   TOC         vstamp      entry
> > 0x0005      0x0003      0x20059418  0x0001      0x20039c6c
> > 
> > maxSTACK     maxDATA     SNbss       magic       modtype
> > 0x00000000  0x00000000  0x0003      0x010b        1L
> 
> Bingo - maxDATA of 0x00000000.  Ken's posting was correct.  You have
> 1x256MB segment of memory available per process.
> 
> If you watch your server process while this is happening, it will be
> hitting 256MB in size.  
> 
> Upping this limit is probably the way to go.  You can use the ldedit
> command to up this limit for your binaries, or specify it when you build
> Postgres.  See the file docs/FAQ_AIX with the PG source for details.
-- 
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.