On 20-12-2011 07:27, Magnus Hagander wrote: > On Tue, Dec 6, 2011 at 19:06, Robert Haas <robertmh...@gmail.com> wrote: >> On Tue, Dec 6, 2011 at 1:00 PM, Euler Taveira de Oliveira >> <eu...@timbira.com> wrote: >>> On 06-12-2011 13:11, Robert Haas wrote: >>>> On Tue, Dec 6, 2011 at 5:14 AM, Magnus Hagander <mag...@hagander.net> >>>> wrote: >>>>> I've been considering similar things, as you can find in the archives, >>>>> but what I was thinking of was converting the number to just a plain >>>>> bigint, then letting the user apply whatever arithmetic wanted at the >>>>> SQL level. I never got around to acutally coding it, though. It could >>>>> easily be extracted from your patch of course - and I think that's a >>>>> more flexible approach. Is there some advantage to your method that >>>>> I'm missing? >>>> >>>> I went so far as to put together an lsn data type. I didn't actually >>>> get all that far with it, which is why I haven't posted it sooner, but >>>> here's what I came up with. It's missing indexing support and stuff, >>>> but that could be added if people like the approach. It solves this >>>> problem by implementing -(lsn,lsn) => numeric (not int8, that can >>>> overflow since it is not unsigned), which allows an lsn => numeric >>>> conversion by just subtracting '0/0'::lsn. >>>> >>> Interesting approach. I don't want to go that far. If so, you want to change >>> all of those functions that deal with LSNs and add some implicit conversion >>> between text and lsn data types (for backward compatibility). As of int8, >>> I'm > > As long as you have the conversion, you don't really need to change > them, do you? It might be nice in some ways, but this is still a > pretty internal operation, so I don't see it as critical. > For correctness, yes.
At this point, my question is: do we want to support the lsn data type idea or a basic function that implements the difference between LSNs? -- Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers