Re: More AIX 5.3 fun - out of memory ?

Gavin Hamill wrote:
> Having successfully got pg 8.1.3 to run, I'm simply trying to pg_restore
> a dump from our live server. However, even very soon into the restore, I
> get these messages from the autovacuum daemon once per minute:
[...]
> 2006-03-28 14:15:35 BSTERROR: out of memory
> 2006-03-28 14:15:35 BSTDETAIL: Failed on request of size 268435452.
>
> Out of memory? This machine is dedicated to pg and has 16GB of RAM
> installed! My AIX knowledge is next to zero, but I'm hoping this helps:
[...]
> I've checked that the 'postgres' user does not have any limits set with
> smitty, and then logged out + in again, but when I restart the
> postmaster, I immediately get the same errors from autovac.
>
> This is doubtless some AIX feature that I simply don't know about,
> rather than any interaction as a result of pg itself, but AIX admins
> must have come across this before :(

You're using a 32-bit build with the default memory model, it would
seem. You're limited to less than 256MB for the heap in that model.
Try stopping the postmaster and starting it back up with the environment
variable LDR_CNTRL set to "MAXDATA=0x80000000". This expands the heap
to 2GB and if it helps, you can use ldedit on your postgres binaries to
make that the default (or rebuild, passing the linker
"-bmaxdata:0x80000000").

Anyway, "Large Program Support"[1] from the AIX docs give an overview of
the situation. Chapter 3 of the redbook "Developing and Porting C and
C++ Applications on AIX"[2] goes into all the gory details of what's
happening.

[1]
http://publib.boulder.ibm.com/infocenter/pseries/topic/com.ibm.aix.doc/aixprggd/genprogc/lrg_prg_support.htm
[2] http://www.redbooks.ibm.com/abstracts/sg245674.html?Open
--
Seneca Cunningham
scunning(at)ca(dot)afilias(dot)info