Re: PostgreSQL on 64 bit Linux
От | mark@mark.mielke.cc |
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Тема | Re: PostgreSQL on 64 bit Linux |
Дата | |
Msg-id | 20060821131646.GB15841@mark.mielke.cc обсуждение исходный текст |
Ответ на | Re: PostgreSQL on 64 bit Linux (Douglas McNaught <doug@mcnaught.org>) |
Ответы |
Re: PostgreSQL on 64 bit Linux
Re: PostgreSQL on 64 bit Linux Re: PostgreSQL on 64 bit Linux |
Список | pgsql-hackers |
On Sun, Aug 20, 2006 at 11:00:26PM -0400, Douglas McNaught wrote: > mark@mark.mielke.cc writes: > > Is there an interest, or any active project to examine PostgreSQL in > > the area of 64-bit processors? Has it already been done? I don't recall > > seeing a reference to it in my travels. I'm also not sure on what to > > expect for results, as the territory is still new. 64-bit processors > > have existed for a while, but 32-bit processors have been the popular > > choice, making 64-bit support an after thought? > I find this question a bit amusing, since PG has run on 64-bit > architectures such as MIPS, Sparc, Alpha and PA-RISC for quite a while > now. :) I don't think so. Software can be designed to take best advantage of hardware. Recompiling it for a different architecture, running test cases, and declaring support, is not the same as optimizing for. > As I said in a private email to Naz, the main advantage I think you'd > see from 64-bit is the ability to run with more than 2GB or so of > shared buffers on a system with lots of RAM. Whether you'd want to do > that, or let the OS do most of the buffering, is an open question... This is what I mean by after thought. PostgreSQL is designed for 32-bit processors. Which is fine. I'm not complaining. The question was whether there is an interest in pursuing 64-bit specific optimizations. In the PostgreSQL code, a quick check points me only to "has long int 64" as a 64-bit source code #ifdef. Of the six places that reference this, five of them actually slow down the code, as they check for overflow of the 'long int' result beyond 4 bytes of data. The sixth place is used to define the 64-bit type in use by PostgreSQL, which I suspect is infrequently used. I believe the answer is no. No or few 64-bit optimization possibilities have been chased down, probably because some or many of these would: 1) require significant re-architecture 2) reduce the performance in a 32-bit world It's a question that only half interests me. As with most projects, I don't think the projects are ready to re-architect for this purpose. Perhaps once 50%+ of people are running PostgreSQL in 64-bit mode, the question will be more serious to more people. As a half interesting question, I'm defending it as a valid question. Please don't write it off, but it is fine to say "not yet, we have more important things to work on". Cheers, mark -- mark@mielke.cc / markm@ncf.ca / markm@nortel.com __________________________ . . _ ._ . . .__ . . ._. .__ . . . .__ | Neighbourhood Coder |\/| |_| |_| |/ |_ |\/| | |_ | |/ |_ | | | | | | \ | \ |__ . | | .|. |__ |__ | \ |__ | Ottawa, Ontario, Canada One ring to rule them all, one ring to find them, one ring to bring them all and in the darkness bindthem... http://mark.mielke.cc/
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