Thread: Minimising disk writes
Hi, I'm at the investigation stage of a project that involves putting a database on an embedded device. One of the problems we face is that the filesystem is on Flash Memory so we need to minimize any writes. Looking at the docs, it seems that temp_buffers, and work_mem are the two variables we might play about with to achieve this. Are there any others I should be aware of? Is it just a bad idea to use postgresql for this type of thing? Regards, Andy ___________________________________________________________ Try the all-new Yahoo! Mail. "The New Version is radically easier to use" The Wall Street Journal http://uk.docs.yahoo.com/nowyoucan.html
Andy Chambers <andychambers2002@yahoo.co.uk> writes:
> I'm at the investigation stage of a project that involves putting a
> database on an embedded device. One of the problems we face is that
> the filesystem is on Flash Memory so we need to minimize any writes.
> Is it just a bad idea to use postgresql for this type of thing?
Fraid so ... PG is not designed with the idea of avoiding disk writes,
indeed it's pretty aggressive at pushing committed data out to disk.
You could maybe get away with flash storage for a read-mostly, very
low update rate database, but the software isn't going to help you
do it :-(
regards, tom lane
On 8/12/06, Tom Lane <tgl@sss.pgh.pa.us> wrote: > > I'm at the investigation stage of a project that involves putting a > > database on an embedded device. One of the problems we face is that > > the filesystem is on Flash Memory so we need to minimize any writes. > > Is it just a bad idea to use postgresql for this type of thing? > Fraid so ... PG is not designed with the idea of avoiding disk writes, > indeed it's pretty aggressive at pushing committed data out to disk. > You could maybe get away with flash storage for a read-mostly, very > low update rate database, but the software isn't going to help you > do it :-( How feasible would it be to have the pg_data structure copied from the Flash to e.g. a RAM disk, and only write it back occasionally? Or have the "busier" parts, if the application has such, in RAM. Of course I have no idea how big the flash-memory and the actual RAM are, and the idea may be completely off. Cheers, Andrej
* Tom Lane <tgl@sss.pgh.pa.us> [2006-08-11 08:41:16 -0400]: > Andy Chambers <andychambers2002@yahoo.co.uk> writes: > > I'm at the investigation stage of a project that involves putting a > > database on an embedded device. One of the problems we face is that > > the filesystem is on Flash Memory so we need to minimize any writes. > > > Is it just a bad idea to use postgresql for this type of thing? > > Fraid so ... PG is not designed with the idea of avoiding disk writes, > indeed it's pretty aggressive at pushing committed data out to disk. > You could maybe get away with flash storage for a read-mostly, very > low update rate database, but the software isn't going to help you > do it :-( I assumed that one can't really avoid writing to disk when committing data (do any free databases try to avoid this?). I was more worried about temporary tables created in join and sort operations. Thanks, Andy ___________________________________________________________ Copy addresses and emails from any email account to Yahoo! Mail - quick, easy and free. http://uk.docs.yahoo.com/trueswitch2.html