Re: Copying large tables with DBLink

From: Joe Conway <mail(at)joeconway(dot)com>
To: Chris Hoover <revoohc(at)sermonaudio(dot)com>
Cc: PostgreSQL Admin <pgsql-admin(at)postgresql(dot)org>
Subject: Re: Copying large tables with DBLink
Date: 2005-03-24 19:21:10
Message-ID: 42431326.2010908@joeconway.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-admin

Chris Hoover wrote:
> Has anyone had problems with memory exhaustion and dblink? We were
> trying to use dblink to convert our databases to our new layout, and had
> our test server lock up several times when trying to copy a table that
> was significantly larger than our memory and swap.
> Basically where were doing an insert into <table> select * from
> dblink('dbname=olddb','select * from large_table) as t_large_table(table
> column listing);
>
> Does anyone know of a way around this?

dblink just uses libpq, and libpq reads the entire result into memory.
There is no direct way around that that I'm aware of. You could,
however, use a cursor, and fetch/manipulate rows in more reasonably
sized groups.

HTH,

Joe

In response to

Browse pgsql-admin by date

  From Date Subject
Next Message Tom Lane 2005-03-24 19:40:22 Re: Copying large tables with DBLink
Previous Message Chris Hoover 2005-03-24 18:59:44 Copying large tables with DBLink