On 2005-07-07, Stephen Frost <sfrost@snowman.net> wrote:
>
>> * truncate is not MVCC-safe.
>
> Erm, that's why it gets a stronger lock, so I don't really see what
> this has to do with it.
It's not MVCC-safe even with the AccessExclusive lock; it damages snapshots
that were taken before the truncate operation but which don't have a lock
on the table yet. The only reason it doesn't break pg_dump is that the
first thing that pg_dump does is to take AccessShare locks on every table
that it's going to dump.
--
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services