Re: pg_dump in a production environment

Thomas F. O'Connell wrote:

> I have a web application backed by a PostgreSQL 7.4.6 database. It's
> an application with a fairly standard login process verified against
> the database.
>
> I'd like to use pg_dump to grab a live backup and, based on the
> documentation, this would seem to be a realistic possibility. When I
> try, though, during business hours, when people are frequently logging
> in and otherwise using the application, the application becomes almost
> unusable (to the point where logins take on the order of minutes).

Could this be an I/O saturation issue like the one the vacuum delay
settings are supposed to help with? Perhaps we could either extend the
vacuum delay settings to effect pg_dump, or make new option to pg_dump
that would have it slow down the dump.

BTW, have you tried running pg_dump from a separate machine? Or even
just making sure that the dump file is being written to a different disk
drive than PostgreSQL is running on. All that disk write activity is
bound to slow the system down.

Matthew