On 2016-05-05 06:08:39 +0300, Ants Aasma wrote: > On 5 May 2016 1:28 a.m., "Andres Freund" <and...@anarazel.de> wrote: > > On 2016-05-04 18:22:27 -0400, Robert Haas wrote: > > > How would the semantics change? > > > > Right now the time for computing the snapshot is relevant, if > > maintenance of xids is moved, it'll likely be tied to the time xids are > > assigned. That seems perfectly alright, but it'll change behaviour. > > FWIW moving the maintenance to a clock tick process will not change user > visible semantics in any significant way. The change could easily be made > in the next release.
I'm not convinced of that - right now the timeout is computed as a offset to the time a snapshot with a certain xmin horizon is taken. Moving the computation to GetNewTransactionId() or a clock tick process will make it relative to the time an xid has been generated (minus a fuzz factor). That'll behave differently in a number of cases, no? -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
