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Re: [Monotone-devel] [PATCH] pre-cache database file to improve response
From: |
Petr Ovtchenkov |
Subject: |
Re: [Monotone-devel] [PATCH] pre-cache database file to improve response time |
Date: |
Tue, 21 Mar 2006 09:10:40 +0300 |
User-agent: |
KMail/1.8.3 |
On Monday 20 March 2006 23:57, Johan Bolmsjö wrote:
> Joe Wilson wrote:
>
> >--- Ulrich Drepper <address@hidden> wrote:
> >
> >
> >>Joe Wilson wrote:
> >>
> >>
> >>Modern OSes have support for hints to the OS. For mmap() calls on
> >>Linux, there is the MAP_POPULATE flag. For all file operations, there
> >>is posix_fadvise().
> >>
> >>
> >
> >SQLite does not use mmap() - just basic read()s and write()s for
> >portability. Can the system calls you mention be made to work
> >with Monotone without altering SQLite's library code?
> >(Does Windows natively support mmap()?)
> >
> >
> Hello,
>
> Slightly OT, but in answer to the last question.
> There is mmap functionality in windows, see:
>
> CreateFile
> CreateFileMapping,
> MapViewOfFile,
> UnmapViewOfFile
> CloseHandle
Well, boosting io operations using mmap on Windows is a well-known
workaround for bad io subsystem design in supermegaOS. Pls, don't
propagate this _workaround_ for other.
- Petr