Yes, I guess I am trying to figure out which poison to pick :-)
So here is what I need:
1. Lowest possible writes to the NAND.
2. Highest possible database reliability in situations of power
outage/reboots
since the device is unmonitored.
3. Am ok with losing 2-5 minutes of data as long as 2 is not compromised.
I think keeping temp files in memory is a good idea but i was concerned
as I read at a few places that if rollback journals are kept in memory then
on power outage
you not only lose the 2 minutes data but can have a corrupt DB in hand as
there
is no journal to lookup to for rollbacks. Is that correct?
It seems WAL with SYNC=NORMAL and SQLITE_TEMP_STORE=3 is the right way
to go as it will always maintain my DB in good state even if I lose 2
minutes of
data.
Thanks all for the quick help,
Pankaj
On Mon, Aug 30, 2010 at 6:20 PM, Black, Michael (IS) <michael.bla...@ngc.com
> wrote:
> Well...yeh...but you were complaining about the logs being written to your
> flash...you gotta' pick your poison.
>
> If you keep only the temporary files in memory you should be OK. That's
> what the compilation flag is for.
>
> Keeping your entire database in memory is probably on an option if it's
> small.
>
> Do you grow your database forever? Or is there some limit to what you're
> doing I assume?
>
> If you're happy with the 660 writes-per-day from your 2-minute transaction
> than the previous solutions (WAL, synchrnous, -DSQLITE_TEMP_STORE=3) should
> make you happy. You'll only stand to lose the 2-minute transaction which is
> where you were when you started this thread.
>
>
> Michael D. Black
> Senior Scientist
> Advanced Analytics Directorate
> Northrop Grumman Information Systems
>
>
> ________________________________
>
> From: sqlite-users-boun...@sqlite.org on behalf of Pankaj Chawla
> Sent: Mon 8/30/2010 7:21 AM
> To: General Discussion of SQLite Database
> Subject: EXTERNAL:Re: [sqlite] Sqlite on NAND flash devices...
>
>
>
> HI Michael,
>
> Thanks for the reply. Wont keeping things in memory lead to chances of
> db getting corrupt especially in cases of power failure or device reboots.
> I am not sure but since Sqlite is now used so frequently in embedded
> devices
> and most devices use flash memories how are these situations mitigated.
> Are there are papers/best practices available that can help. It seems to be
> that if we try to reduce NAND writes by doing things in memory we lose on
> reliability and the way to increase reliability is to do frequent writes.
> Is
> that
> a correct understanding?
>
> Thanks
> Pankaj
>
>
>
>
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> sqlite-users@sqlite.org
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>
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