I have been in favor of using GMP for decimal and possibly for other math operations for about a year now.
so ++ Jobin Augustine wrote: > Voting for Brian to go for GMP. > because almost all linux distributions already contains GMP library. just > like libc. so this cannot be considered as additional dependency. > this is one of the heavily used library. well tested and stable. > this way we can avoid reinventing the wheel. > > if existing code is using string for this. its really bad. > > -Jobin > > > > On Sun, Nov 1, 2009 at 4:05 AM, Brian Aker <[email protected]> wrote: > >> Hi! >> >> On Oct 31, 2009, at 11:59 AM, John David Duncan wrote: >> >> The final result is not easy to grok. (Base 10^9?? One's complement!? And >>> as Sheeri said, how big on disk??) But decimal.c is really only about 3,000 >>> lines of code, including a 100-line comment on the SQL standard and a >>> 200-line test suite. GMP is more like 50,000 lines. >>> >> GMP can do a lot more feature-wise and can handle a much larger set of >> numbers then what the hand written one can. >> >> So I'd like to make the case that it's pretty remarkable code. A database >>> *must* have a fixed decimal type, this design has some real advantages over >>> others, and there's nothing else out there that you can really just drop in >>> to replace it. >>> >> Looking at the code there really isn't much in the way of tests (200 lines >> is pretty small). One of the other things I noticed was that when reading >> the comments I found that it followed the standard bug for bug (aka... >> behavior wise). Is that really way someone expects? >> >> I went and looked at the one PG is using. No limitations on size, doesn't >> follow the SQL standard,... >> >> I'm not sure that I buy the disk format being the absolute best. Internally >> when it was pushed several folks pointed out other solutions which, I have >> no idea, might have been better then this one. What I do know though is that >> it is not that complete. >> >> One question I ask myself... do we want to have to extend this library to >> add additional functions? For that matter, what functions matter for a >> database beyond comparison operations? There was a good argument to go with >> the GMP since it was complete, widely used, and had a community that worked >> on it. While right now? We will be stuck extending our own library, that >> only we use. >> >> There is also the question of numerical constraint, what matters? >> >> I'm on the fence. I know this will go sometime, but I don't know when. I >> hate creating upgrade paths though. >> >> Cheers, >> -Brian >> >> >>> I'd urge you folks to consider giving the decimal library a new lease on >>> life by reusing it in drizzle. >>> >>> >>> >>> On Oct 30, 2009, at 11:44 AM, Brian Aker wrote: >>> >>> Hi! >>>> I'm working through some reference checking right now, and decided to >>>> look at decimal. Just for those playing along at home, up until 5.0 MySQL >>>> just stored DECIMAL as a string, mostly, and did all operations on it >>>> through normal mathematical operations. Starting in 5.0 we switched to a >>>> library and internal developer wrote which should mimic the SQL standard >>>> (and if you read the header in the subject you can find out some of the >>>> absurd bits it is doing). >>>> >>>> Would anyone care if we dropped this in favor of just using one of the >>>> GNU based arbitrary libraries in the future? GMP perhaps (though it is not >>>> quite the same)? I'm a minimalist when it comes to built in types so I tend >>>> to favor this approach, but I would like to hear from others as well. >>>> >>>> Cheers, >>>> -Brian >>>> >>>> BTW any thoughts on long double over our current use of double? It looks >>>> like it would be a mess. >>>> >>>> _______________________________________________ >>>> Mailing list: >>>> https://launchpad.net/~drizzle-discuss<https://launchpad.net/%7Edrizzle-discuss> >>>> Post to : [email protected] >>>> Unsubscribe : >>>> https://launchpad.net/~drizzle-discuss<https://launchpad.net/%7Edrizzle-discuss> >>>> More help : https://help.launchpad.net/ListHelp >>>> >>> >> _______________________________________________ >> Mailing list: >> https://launchpad.net/~drizzle-discuss<https://launchpad.net/%7Edrizzle-discuss> >> Post to : [email protected] >> Unsubscribe : >> https://launchpad.net/~drizzle-discuss<https://launchpad.net/%7Edrizzle-discuss> >> More help : https://help.launchpad.net/ListHelp >> > > > ------------------------------------------------------------------------ > > _______________________________________________ > Mailing list: https://launchpad.net/~drizzle-discuss > Post to : [email protected] > Unsubscribe : https://launchpad.net/~drizzle-discuss > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
