Re: SQLite inserts slow
Sebastien Bigaret <[email protected]> 29 Jun 2004 20:37:55 +0200
| Newsgroups | gmane.comp.python.modeling |
|---|---|
| Message-ID | <[email protected]> |
Ok fine, and indeed, I've just read the documentation http://www.hwaci.com/sw/sqlite/lang.html#pragma and this definitely seems to be far less dangerous than what I thought it could be. Do you think this could be useful enough to have a setting to control that within the framework? For example we could have a env.variable 'SQLITE_SYNCHRONOUS_MODE' set to either 'NORMAL' (default), 'FULL' or 'OFF', an env.var. that the framework could use to set the synchr.mode when opening a connection. While we're at it, are there other PRAGMAs that you all using sqlite think they should be controlled in the same way? -- Sébastien. Ernesto Revilla <[email protected]> wrote: > Hi again, > > Sebastien Bigaret escribió: > > >>Interesting enough that the following instruction makes it much faster > >>causing SQLite to turn off disk sync: > >>*PRAGMA default_synchronous = OFF; > >> > > > >Yes, but this makes the sqlite-db file very fragile, I believe this can > >completely waste your data when some errors happen, or am I wrong? (no > >time to check that in details right now) > > > > > It depends. sqlite writes all changes to a journal file, and when commiting > processes the journal file and appends the results to the end of the > file. The fragile point is after the journal file has been processed, bu > before the data has been written to disk. Of course, this makes it more > fragile, but the probability of a system crash is not very high, provided we > are using powersupplies and stable OS. If we have a patch for this issue, > I'll turn on syncing again. > > With best regards, > Erny ------------------------------------------------------- This SF.Net email sponsored by Black Hat Briefings & Training. Attend Black Hat Briefings & Training, Las Vegas July 24-29 - digital self defense, top technical experts, no vendor pitches, unmatched networking opportunities. Visit www.blackhat.com