From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-06-18T00:50:33+09:00
Subject: Re: Nitro + Og 0.19.0: Og reloaded part2!

On Sat, 18 Jun 2005, George  Moschovitis wrote:

>>> experimental In-Memory/Filesystem adapter.
>> have you played with using sqlite's in memory tables to leverage it's features
>> for this?
>
> Hello,
>
> this is a pure ruby Og store implementation. A KirbyBase store will be
> available soon as well (when I find time to finish it, or if someone
> sends me a patch ;-))
>
> I don't know anything about SQLite3's memory tables is this a different
> table type like the Hash tables or InnoDB tables in Mysql? (btw 0.19.0
> adds support for mysql table types).

you just specify the table as being in memory and use them normally - only
they never hit disk.  another, *nix specific, approach i use a lot is
(essentially)

   begin
     FileUtils::cp 'db', '/dev/shm/db'
     db = SQLite::Database::new '/dev/shm/db'
     yield db
   ensure
     FileUtils::mv '/dev/shm/db', 'db'
   end

which really helps out in some situations since the 'file' is really just in
memory so all intermediate writes and reads do not hit disk and only the
initial/final state requires disk activity.  this means a power failure loses
everything after the first copy but this is often acceptable.

i also would add that, in practice, you should lock the db using posixlock
while moving in case an errant process is modifying the db during the copy...

cheers.

-a
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