Re: [HACKERS] Upgrades for 6.4.1
От | Oleg Bartunov |
---|---|
Тема | Re: [HACKERS] Upgrades for 6.4.1 |
Дата | |
Msg-id | Pine.GSO.3.96.SK.981219130610.11478B-100000@ra обсуждение исходный текст |
Ответ на | Re: [HACKERS] Upgrades for 6.4.1 ("Thomas G. Lockhart" <lockhart@alumni.caltech.edu>) |
Список | pgsql-hackers |
On Sat, 19 Dec 1998, Thomas G. Lockhart wrote: > Date: Sat, 19 Dec 1998 02:58:32 +0000 > From: "Thomas G. Lockhart" <lockhart@alumni.caltech.edu> > To: Jan Wieck <jwieck@debis.com> > Cc: hannu@trust.ee, maillist@candle.pha.pa.us, hackers@postgreSQL.org > Subject: Re: [HACKERS] Upgrades for 6.4.1 > > > Easy - and the type coersion stuff helps alot! > > Up to now (1.5 hours hacking) I have a NUMERIC type that > > handles '+' completely, including overflow checks and > > rounding. > > Neat. I was poking around waiting on a freeware extended-precision > numerical package, but hadn't found anything with a BSD-style license. Did you try search SAL ( Sci. Application for Linux) ? I just did search for 'precision' and found abot 12 items. Don't know about license bit some of them like <a href="http://www.hut.fi/~mtommila/apfloat/">apfloat - A C++ High Performance Arbitrary Precision Arithmetic Package</a> are freeware. >From web page: Apfloat is a high performance arbitrary precision package. That means you can do calculations involving millions of digits with it. It uses Number Theoretic Transforms . It's simple to use. It's fast. It's freeware. > > > Another tricky part I expect when telling the parser that a > > literal NUMERIC must not be enclosed into single quotes. > > This is probably the worst part, since you would hate to take the hit > representing everything as extended precision even if the actual range > is int4/float8. Perhaps we can read as those, but if we get a failure > then escalate to your extended precision type(s). The automatic type > conversion stuff should convert later if necessary, so it might be > transparent and relatively fast. > > > The only ugly thing is, that I needed to put the precision > > AND the scale together into atttypmod (I limited both to 99 > > for now and put them as prec<<8 | scale into). So pg_dump > > will need attention later. > > As Bruce points out, that was anticipated (but I agree it's ugly). Shift > over 16 bits if you want... > > Congrats! > > - Tom > _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
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