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Pg_dump makes me nut !

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  Pg_dump makes me nut ! DeepThought <ilmio@ilmioserverdiposta.it> - 2015-12-18 13:00 +0100
    Re: Pg_dump makes me nut ! Dimitri Fontaine <dimitri@2ndQuadrant.fr> - 2015-12-18 13:12 +0100
    Re: Pg_dump makes me nut ! Robert Klemme <shortcutter@googlemail.com> - 2015-12-19 21:38 +0100
    Re: Pg_dump makes me nut ! DFS <nospam@dfs.com> - 2017-05-11 07:44 -0400

#687 — Pg_dump makes me nut !

Hi guys,

well.. this is a strange problem. I've deeply searched over all forums 
but I've found nothing at all. Thanks in advance 4 answers.

I have a database composed by 3 different schemas: one of them (called 
"notsobigschema" :P ) has a table of about 30Gigs, and with a single 
table of 19Gigs inside. This table is full of LOBs and I don't know why 
part of it seem in pg_toast_$tableoid and part of it in pg_largeobject. 
But this is not the problem.

When I use pg_dump to make a db backup, it takes all memory and swap 
available and kernel kills pg_dump session caused a out of memory 
exception . I have a RAM of about 8Gb  and a pair of swap.
  When I use a *pg_dump -n notsobigschema * , it succeded and finish 
with success.
Obiuvsly, u can say, "schema flag exclude blob from dump". True. But in 
-n schema mode, pg_dump takes all RAM+SWAP too.

So.. HOw can I explain ? DO the biggest table (without LOB ) fit 
perfectly in sum of RAM+SWAP , considering total consumption of memory ?
Have pg_dump a different behaviour in memory managment when manages LOB ?


How may can I limit pg_dump memory consumption to  fit my resources?

Thanks a lot

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#688

Hi,

Please consider asking on the pgsql-general mailing list instead:

  http://www.postgresql.org/list/pgsql-general/

Regards,

DeepThought <ilmio@ilmioserverdiposta.it> writes:
> well.. this is a strange problem. I've deeply searched over all forums but
> I've found nothing at all. Thanks in advance 4 answers.
>
> I have a database composed by 3 different schemas: one of them (called
> "notsobigschema" :P ) has a table of about 30Gigs, and with a single table
> of 19Gigs inside. This table is full of LOBs and I don't know why part of it
> seem in pg_toast_$tableoid and part of it in pg_largeobject. But this is not
> the problem.
>
> When I use pg_dump to make a db backup, it takes all memory and swap
> available and kernel kills pg_dump session caused a out of memory exception
> . I have a RAM of about 8Gb  and a pair of swap.
>  When I use a *pg_dump -n notsobigschema * , it succeded and finish with
> success.
> Obiuvsly, u can say, "schema flag exclude blob from dump". True. But in -n
> schema mode, pg_dump takes all RAM+SWAP too.
>
> So.. HOw can I explain ? DO the biggest table (without LOB ) fit perfectly
> in sum of RAM+SWAP , considering total consumption of memory ?
> Have pg_dump a different behaviour in memory managment when manages LOB ?
>
>
> How may can I limit pg_dump memory consumption to  fit my resources?

-- 
Dimitri Fontaine
PostgreSQL DBA, Architecte

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#689

On 18.12.2015 13:00, DeepThought wrote:

> How may can I limit pg_dump memory consumption to  fit my resources?

Just a wild guess: maybe you memory settings are generally way off, i.e. 
you have configured the DB to use too much mem as max and the max is not 
reached during regular operations.

Kind regards

	robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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#764

On 12/18/2015 7:00 AM, DeepThought wrote:
> Hi guys,
> 
> well.. this is a strange problem. I've deeply searched over all forums 
> but I've found nothing at all. Thanks in advance 4 answers.

http://www.urbandictionary.com/define.php?term=Nut

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