Re: BUG #1331: after update: vacuum blocks parallel to select

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Enke, Michael" <michael.enke@wincor-nixdorf.com>
Cc: pgsql-bugs@postgresql.org
Date: 2004-11-29T16:27:14Z
Lists: pgsql-bugs
"Enke, Michael" <michael.enke@wincor-nixdorf.com> writes:
> But the description says: vacuum can run parallel to selects.
> This is than not true.

Sure it can; but that doesn't mean there is no interlocking at all.

The issue you have is not so much that the select is running as that it
is *not* running, ie, it's stopped on a particular page.  As soon as it
moves off the modified page, the vacuum will be able to make progress.

			regards, tom lane