On 2017-10-02 17:57:51 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > Done that way. It's a bit annoying, because we've to take care to > > initialize the "unused" part of the array with a valid signalling it's > > an unused mapping. Can't use 0 for that because fmgr_builtins is a > > valid entry. > > The prototype code I posted further upthread just used -1 as the "unused" > marker. There's no reason the array can't be int16 rather than uint16, > and "if (index < 0)" is probably a faster test anyway.
Right, but whether we use -1 or UINT16_MAX or such doesn't matter. The relevant bit is that we can't use 0, so we can't rely on the rest of the array being zero initialized, but instead of to initialize all of it explicitly. I've no real feelings about using -1 or UINT16_MAX - I'd be very surprised if there's any sort of meaningful performance difference. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers