On Thu, Oct 8, 2015 at 2:07 PM, Peter Geoghegan <p...@heroku.com> wrote: > On Thu, Oct 8, 2015 at 10:13 AM, Robert Haas <robertmh...@gmail.com> wrote: >> It seems to me that (1) ABBREV_STRING_UINT isn't >> a great name for this and (2) the comment is awfully long for the >> thing to which it refers. I suggest that we instead call it >> DatumToBigEndian(), put it pg_bswap.h, and change the comments to >> something like this: >> >> /* >> * Rearrange the bytes of a Datum into big-endian order. >> * >> * One possible application of this macro is to make comparisons >> cheaper. An integer >> * comparison of the new Datums will return the same result as a memcmp() on >> the >> * original Datums, but the integer comparison should be much cheaper. >> */ >> >> The specific way that this is used by various sortsupport routines can >> be adequately explained in the comments for those routines. > > This is pretty clearly something specific to SortSupport. I'm not > opposed to changing the name and making the comments more terse along > those lines, but I think it should live in sortsupport.h. The macro > byteswaps datums on little-endian platforms only, which seems very > specific. > > I think that we're going to have SortSupport with abbreviation for > UUIDs and bytea at some point, and maybe character(n). Centralizing > information about this to sortsupport.h makes sense to me.
I'm not convinced. Doesn't this exact same concept get used for over-the-wire communication between BE and LE machines? There, this operation is spelled htonl/ntohl. Some systems even have htonll, but I'm sure there are still a bunch that don't. -- 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
