> > The plural seems better to me; there's no such thing as a solitary
> > synchronized scan, no? The whole point of the feature is to affect
> > the behavior of multiple scans.
>
> +1. The plural is important IMHO.
ok, good.
> As I stated earlier, I don't really like this argument (we already
> broke badly designed applications a few times in the past) but we
> really need a way to guarantee that the execution of a query is stable
> and doesn't depend on external factors. And the original problem was
> to guarantee that pg_dump builds a dump as identical as possible to
> the existing data by ignoring external factors. It's now the case with
> your patch.
> The fact that it allows us not to break existing applications relying
> too much on physical ordering is a nice side effect though :).
One more question. It would be possible that a session that turned off
the synchronized_seqscans still be a pack leader for other later
sessions.
Do/should we consider that ?
The procedure would be:
start from page 0
iff no other pack is present fill the current scan position for others
Andreas