Re: Hash join in SELECT target list expression keeps consuming memory

On 03/21/2018 02:18 PM, Jaime Soler wrote:
> Hi,
> 
> We still get out of memory error during pg_dump execution
> ...
> pg_dump: reading row security enabled for table "public.lo_table"
> pg_dump: reading policies for table "public.lo_table"
> pg_dump: reading publications
> pg_dump: reading publication membership
> pg_dump: reading publication membership for table "public.lo_table"
> pg_dump: reading subscriptions
> pg_dump: reading large objects
> out of memory
> 

Hmmmm ... that likely happens because of this for loop copying a lot of
data:

https://github.com/postgres/postgres/blob/master/src/bin/pg_dump/pg_dump.c#L3258

But I'm having trouble verifying that, because the query fetching the
list of objects is rather expensive with this number of large objects.
How long does it take for you? I wonder if there's a way to make the
query faster.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services