On Fri, Jun 24, 2011 at 1:08 PM, Kevin Grittner <kevin.gritt...@wicourts.gov> wrote: >> What I think we should do is replace the existing paragraph with >> something along these lines: >> >> The <structname>pg_locks<structname> view displays data from both >> the regular lock manager and the predicate lock manager, which are >> separate systems. When this view is accessed, the internal data >> structures of each lock manager are momentarily locked, and copies >> are made for the view to display. Each lock manager will >> therefore produce a consistent set of results, but as we do not >> lock both lock managers simultaneously, it is possible for locks >> to be taken or released after we interrogate the regular lock >> manager and before we interrogate the predicate lock manager. >> Each lock manager is only locked for the minimum possible time so >> as to reduce the performance impact of querying this view, but >> there could nevertheless be some impact on database performance if >> it is frequently accessed. > > I agree that it's probably better to document it than to increase > the time that both systems are locked. If we get complaints about > it, we can always revisit the issue in a later release. > > The above wording looks fine to me.
OK, committed that change. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
