Robert Haas escribió: > On Fri, Dec 20, 2013 at 7:22 AM, Andres Freund <and...@2ndquadrant.com> wrote: > >> Maybe what we should do is add a function something like > >> pg_tuple_header(tableoid, ctid) that returns a record, maybe something > >> like (rawxmin xid, rawxmax xid, rawcid cid, infomask int, infomask2 > >> int, hoff int). Or perhaps some slightly more cooked version of that > >> information. And then delete the xmin, xmax, cmin, and cmax system > >> columns. That'd save significantly on pg_attribute entries while, at > >> the same time, actually providing more information than we do today. > > > > I was wondering whether we couldn't just pass pg_tuple_header() a whole > > row, instead of having the user manually pass in reloid and ctid. I > > think that should actually work in the interesting scenarios. > > I wondered that, too, but it's not well-defined for all tuples. What > happens if you pass in constructed tuple rather than an on-disk tuple?
I assume without checking that passing reloid/ctid would allow this to work for tuples in a RETURNING clause; and if we ever have an OLD reference for the RETURNING clause of an UPDATE, that it would work there, too, showing the post-update status of the updated tuple. -- Álvaro Herrera 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
