Re: Pg_upgrade speed for many tables

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, Magnus Hagander <magnus@hagander.net>
Date: 2012-11-05T20:14:40Z
Lists: pgsql-hackers
Bruce Momjian <bruce@momjian.us> writes:
> Magnus reported that a customer with a million tables was finding
> pg_upgrade slow.

You sure there's not an O(N^2) issue in there somewhere?

> I don't see anything unsafe about having pg_upgrade use
> synchronous_commit=off.

No objection, but this seems unlikely to be better than linear speedup,
with a not-terribly-large constant factor.

BTW, does pg_upgrade run pg_restore in --single-transaction mode?
That would probably make synchronous_commit moot, at least for that
step.

			regards, tom lane