Re: single task postgresql - Mailing list pgsql-hackers
From | Oleg Bartunov |
---|---|
Subject | Re: single task postgresql |
Date | |
Msg-id | Pine.GSO.4.44.0203061835130.304-100000@ra.sai.msu.su Whole thread Raw |
In response to | Re: single task postgresql (mlw <markw@mohawksoft.com>) |
List | pgsql-hackers |
Mark, I've found "Fast synchronized access to shared memory for Windows and for i86 Unix-es" http://www.ispras.ru/~knizhnik/shmem/Readme.htm Would't be useful ? Regards, Oleg On Wed, 27 Feb 2002, mlw wrote: > Oleg Bartunov wrote: > > > > On Wed, 27 Feb 2002, mlw wrote: > > > > > Greg Copeland wrote: > > > > > > > > Windows does not really have shared memory support. This has been a > > > > beef with the Win32 API for a long time now. Because it has been a long > > > > time complaint, it was finally added in Win2000 and later. Likewise, > > > > I'd like to point out that thinks like sims, shared memory, pipes, etc, > > > > and other entities commonly used for concurrent programming strategies > > > > are slower in XP. So, because shared memory really isn't well > > > > supported, they elected to have what is, in essense, memory mapped > > > > files. Multiple processes then map the same file and read/write to it > > > > as needed, more or less as you would shared memory. Unless you plan on > > > > only targetting on Win 2000 and XP, it sounds like a waste of time. > > > > > > This is not really true. Under DOS windows, i.e. 95,98, etc. Shared memory can > > > be done in 16 bit land with a touch of assembly and a DLL. Allocate, with > > > globalalloc, a shared memory segment. The base selector is a valid 32 bit > > > selector, and the memory is mapped in the above 2G space shared and mapped to > > > all 32bit processes. > > > > > > Under NT through 2K, yes using a memory mapped files is the way to do it, but > > > you do not actually need to create a file, you can use (HANDLE)0xFFFFFFFF, > > > which is the NT equivilent of the system memory file. The handle returned is a > > > system global object which can be shared across processes. > > > > > > > Mark, > > > > do you consider to work on this issue ? > > Yea, let me think about it. What is your time frame? When I offered to work on > it, I thought it could be a leasurely thing. I have to get a machine running > some form of Windows on which to develop and test. > > I want to say yes, and if no one else does it, I will, but I'm not sure what > your timeframe is. If it is the mystical 7.3, then sure I can do it easily. If > you need something quickly, I can help, but I don't think I could shoulder the > whole thing. > > I have a couple things I have promised people. Let me get those done. I will > try to write an equivilent set of functions for shget, shmat, etc. as soon as I > can. Anyone wanting to run with them can hack and test PostgreSQL on Windows. > > How does that sound? > Regards, Oleg _____________________________________________________________ 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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