"Kevin Grittner" <kevin.gritt...@wicourts.gov> writes: > The Cahill thesis mentions an interesting optimization -- they defer > determination of the snapshot until after any locks required for the > first statement have been acquired. Where the first statement was, > for example, an UPDATE, this reduced re-reads or rollbacks in the > face of concurrent modifications. > Does PostgreSQL currently do this?
Yes --- it's not an "optimization", it's necessary for basic functionality to work correctly. See for example the last para at http://www.postgresql.org/docs/8.4/static/applevel-consistency.html regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
