On Fri, Jul 17, 2015 at 4:16 AM, Florent Guiliani <flor...@guiliani.fr> wrote: >> but such an LSN need not exist. Suppose A writes a commit record at >> LSN 0/10000, and then B writes a commit record at 0/10100, and then B >> calls ProcArrayEndTransaction(). At this point, B is visible and A is >> not visible, even though A's commit record precedes that of B. > > Maybe that's what Andres referred as "doable with some finicky locking". > > There is some race conditions to build a snapshot with an associated > consistent LSN. If I understand your example, A is supposed to call > ProcArrayEndTransaction() anytime soon.
Right. > Could we wait/lock until it > happens? In theory, yes. I'm not sure what the code would would look like, though. -- 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
