On Wed, Dec 4, 2013 at 6:33 PM, Peter Geoghegan <p...@heroku.com> wrote: > On Wed, Dec 4, 2013 at 1:59 PM, Robert Haas <robertmh...@gmail.com> wrote: >> Yeah, I think if we can make something like this work, it would be >> neat-o. Getting this working for int4 would be a good win, as Peter >> says, but getting it working for both int4 and int8 with the same code >> would be a significantly better one. > > No arguments here. I think I didn't initially suggest it myself out of > passing concern about the guarantees around how unused Datum bits are > initialized in all relevant contexts, but having looked at it for a > second I see that we are of course disciplined there.
Hmm. And yet, there's this: * When a type narrower than Datum is stored in a Datum, we place it in the * low-order bits and are careful that the DatumGetXXX macro for it discards * the unused high-order bits (as opposed to, say, assuming they are zero). * This is needed to support old-style user-defined functions, since depending * on architecture and compiler, the return value of a function returning char * or short may contain garbage when called as if it returned Datum. And record_image_eq does a rather elaborate dance around here, calling the appropriate GET_x_BYTES macro depending on the type-width. If we can really count on the high-order bits to be zero, that's all completely unnecessary tomfoolery. -- 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
