Re: Out of Memory - 8.2.4

On Aug 28, 2007, at 4:33 PM, Marko Kreen wrote:

> On 8/24/07, Jeff Amiel <becauseimjeff@yahoo.com> wrote:
>> Over last 2 days, have spotted 10 "Out of Memory"
>> errors in postgres logs (never saw before with same
>> app/usage patterns on tuned hardware/postgres under
>> FreeBSD)
>>
>> Aug 22 18:08:24 db-1 postgres[16452]: [ID 748848
>> local0.warning] [6-1] 2007-08-22 18:08:24 CDT   ERROR:
>>  out of memory.
>> Aug 22 18:08:24 db-1 postgres[16452]: [ID 748848
>> local0.warning] [6-2] 2007-08-22 18:08:24 CDT
>> DETAIL:  Failed on request of size 536870910.
>>
>> What I found interesting is that It's ALWAYS the same
>> size....536870910
>>
>> I am running autovacuum and slony.....but I see
>> nothing in the logs anywhere near the "out of memory"
>> errors related to either (autovacuum used to under
>> 8.0.X log INFO messages every time it vacuumed which
>> came in handy...I assume it doesn't so this any more?)
>>
>>
>> The events are fairly spread out...and cannot (by
>> looking at app logs and rest of DB logs) correlate to
>> any specific query or activity.
>>
>> Any help would be appreciated
>
> I've experienced something similar.  The reason turned out to be
> combination of overcommit=off, big maint_mem and several parallel
> vacuums for fast-changing tables.  Seems like VACUUM allocates
> full maint_mem before start, whatever the actual size of the table.
>
> Fix was to put "set maint_mem=32M" before small vacuums and
> serialize some of them.
>

I'm not sure about the OP but I know that we just run autovacuum so
no problem with parallel vacuums.  In addition, Solaris doesn't have
overcommit.

Erik Jones

Software Developer | Emma®
erik@myemma.com
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