> On 20 Mar 2017, at 11:32, Craig Ringer <cr...@2ndquadrant.com> wrote: > > On 19 March 2017 at 21:26, Petr Jelinek <petr.jeli...@2ndquadrant.com> wrote: > >> I think only genam would need changes to do two-phase scan for this as >> the catalog scans should ultimately go there. It's going to slow down >> things but we could limit the impact by doing the two-phase scan only >> when historical snapshot is in use and the tx being decoded changed >> catalogs (we already have global knowledge of the first one, and it >> would be trivial to add the second one as we have local knowledge of >> that as well). > > > TBH, I have no idea how to approach the genam changes for the proposed > double-scan method. It sounds like Stas has some idea how to proceed > though (right?) >
I thought about having special field (or reusing one of the existing fields) in snapshot struct to force filtering xmax > snap->xmax or xmin = snap->xmin as Petr suggested. Then this logic can reside in ReorderBufferCommit(). However this is not solving problem with catcache, so I'm looking into it right now. > On 17 Mar 2017, at 05:38, Craig Ringer <cr...@2ndquadrant.com> wrote: > > On 16 March 2017 at 19:52, Stas Kelvich <s.kelv...@postgrespro.ru> wrote: > >> >> I’m working right now on issue with building snapshots for decoding prepared >> tx. >> I hope I'll send updated patch later today. > > > Great. > > What approach are you taking? Just as before I marking this transaction committed in snapbuilder, but after decoding I delete this transaction from xip (which holds committed transactions in case of historic snapshot). > -- > Craig Ringer http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
