On Tue, Dec 26, 2006 at 09:36:42AM -0800, Ken wrote: > > Your question boils down to this: Can you speed up transactions > > by dropping the durable property - the D in ACID. Yes you > > can. Actually, most client/server database engines already > > do this for you without telling you. Very few client/server > > databases are really ACID - they are usually on ACI when > > confronted with a power failure. > > Are you sure about this? I'm pretty sure PostgreSQL is ACID by default, > and as certain as I can be without proof that the commercial (Oracle etc.) > are as ACID as the hardware they run on. > > They achieve this by not requiring seeks to overwrite data, as the write > ahead log is sequential and so can be written at the sequential IO rate of > the underlying device in the best case.
Indeed, and it might be that SQLite runs significantly faster on filesystems that work that way as well. Even then there's some sort of super-block that has to be updated for a transaction to be durably committed, but one can spread alternats about such that as soon as one is written then the transaction is committed (on recovery you have to find a thread of superblocks, but it's a small trade-off). Nico -- ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
