Hi Stephen Woodbridge,
> (although it might
> > be an interesting academic exercise to make a VFS port of SQLite
> that uses
> > memory arrays for read/write ops.)
Do u have any ref impl of this kind?
regards
ragha
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----- Original Message -----
From: Stephen Woodbridge <[EMAIL PROTECTED]>
Date: Thursday, August 7, 2008 7:24 am
Subject: Re: [sqlite] Loading a existing database 100% into memory
> Stephen Oberholtzer wrote:
> > On Wed, Aug 6, 2008 at 6:26 PM, Brown, Daniel <[EMAIL PROTECTED]>
> wrote:>
> >> Good afternoon list,
> >>
> >> I would like to load my current database file completely into
> memory,>> mostly as an experiment to check SQLite's maximum memory
> footprint,>> however searching through the documentation I can
> only find references
> >> about how to create new databases that are completely memory
> resident.>> Is there a way to do this? I'm currently using the
> SQlite console
> >> application for my testing if that makes a difference.
> >
> >
> > What, exactly, is it you're after? I can load a SQLite database
> 100% into
> > memory quite quickly:
> >
> > int fd = open("sqlitedb.dat");
> > struct stat info;
> > fstat(fd, &info);
> > char *buf = malloc(info.st_size);
> > read(fd, buf, info.st_size);
> >
> > I find it extremely unlikely that this is what you want
> (although it might
> > be an interesting academic exercise to make a VFS port of SQLite
> that uses
> > memory arrays for read/write ops.)
> >
> > At the other end of the spectrum, you could just dump the entire
> database on
> > disk and then insert all the data into a :memory: database.
> However, this
> > doesn't seem like it would be very useful, either.
> >
> > This sounds like an XY problem. What are you really trying to
> accomplish?> What constraints are preventing you from simply using
> an on-disk database?
> >
>
> Another interesting option might be to mmap the DB file so you use
> the
> OS virtual memory paging to map the file to memory as you need
> access to
> it. But this probably has the downside that writes are not sync'd
> to
> disk so in the event of a crash you out of luck, but that is the
> case
> with any memory DB. The upside is that when you shutdown your DB
> is
> sync'd to disk and the OS paging is pretty efficient.
>
> -Steve W
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>
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