On 28 Apr 2010, at 6:53pm, Jay A. Kreibich wrote: > Once (some) pages are written to disk, you have uncommitted changes > in the database file. Allowing readers could "leak" those > uncommitted changes to other database connections, which is not > allowed under the ACID transaction model. > > Further, because only some pages get written out, the database file > might very well be inconsistent and unusable. You need the full > picture of file pages plus cached pages to have a consistent database > image. At that point in time, the file alone cannot provide that. > > Everything is still safe, thanks to the journal file, but no readers > can touch the file until the transaction is either fully committed or > fully rolled back.
Could you add a mode that meant every time /some/ pages were written out, /all/ pages were written out, and the lock could be relaxed back down to RESERVED mode ? Or would that create problems where a lot of transactions had to be committed all at once to keep the database consistent ? Of course, this would slow down situations where one process was going to keep refilling the memory cache, but it would reduces times when one process hogs the EXCLUSIVE lock. Simon. _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
