Re: [sqlite] VACUUM & journal size

> First, I'm sure it is nearly impossible to do this as a > guaranteed, atomic operation on most OSes and filesystems. ... > > Second, if this is meant to look like a cleanup operation on the > original file, the original file (including any filesystem meta-data) > should be kept in-tact.

Re: [sqlite] VACUUM & journal size

On Tue, Mar 16, 2010 at 06:18:13PM +0300, Max Vlasov scratched on the wall: > When I read the comments it was obvious that the algorithm uses very simple > approach: > Attach blank database, copy all data, detach, rename. Sure I might be > wrong in details, but generally it looks like this.

Re: [sqlite] VACUUM & journal size

> So the question is what is so special about sqlite3RunVacuum that it needs > more space than a simple emulation of its actions? I believe renaming of the file cannot be atomic. So in case of OS crash you can be in situation without database at all - no old and no new. Also deleting of old file

Re: [sqlite] VACUUM & journal size

> This means that to VACUUM a SQLite database of size X, you need at > least 2X of _additional_ free disk space available. That seems rather > wasteful, just looking at it as a SQLite user. Although > programmatically there may be reasons for it that I'm not aware of. > > Hmm, did some

Re: [sqlite] VACUUM & journal size

On Mon, Mar 15, 2010 at 11:18 AM, Scott Hess wrote: > AFAICT, the operation to copy the pages back _is_ journaled, and the > journal will get any pages which are overwritten in the front of the > main database.  If the initial database has half of the pages used, it > seems like

Re: [sqlite] VACUUM & journal size

On Mon, Mar 15, 2010 at 11:18:32AM -0800, Scott Hess scratched on the wall: > On Sun, Mar 14, 2010 at 5:18 PM, Jay A. Kreibich wrote: > > ?While I have not tested this, I was under the impression that the > > ?journal file is very very small, as no modifications are made to the >

Re: [sqlite] VACUUM & journal size

On Sun, Mar 14, 2010 at 5:18 PM, Jay A. Kreibich wrote: > On Sun, Mar 14, 2010 at 07:19:59PM -0400, Matthew L. Creech scratched on the > wall: >> I have a SQLite database with one large table, and I'd like to shrink >> the size of that table to free up space in the filesystem.  

Re: [sqlite] VACUUM & journal size

On Mar 14, 2010, at 7:19 PM, Matthew L. Creech wrote: > Hi, > > I have a SQLite database with one large table, and I'd like to shrink > the size of that table to free up space in the filesystem. > > I'm finding that it needs a full 100 MB for the journal, even > though once the VACUUM succeeds

Re: [sqlite] VACUUM & journal size

On Mon, Mar 15, 2010 at 2:11 AM, Matthew L. Creech wrote: > > I'll give this a try tomorrow on a real device with journaling off, > and see how much space it uses in /tmp with journaling turned off. > I ran some tests on a real device with a real database, and got the

Re: [sqlite] VACUUM & journal size

On Sun, Mar 14, 2010 at 9:18 PM, Jay A. Kreibich wrote: > >  Are you sure it is the journal file that is growing too large? > ... > >  Now, if I'm following you correctly, the numbers you gave seem to >  indicate that this should work... If the old database is 100MB and >  the new

Re: [sqlite] VACUUM & journal size

On Sun, Mar 14, 2010 at 07:19:59PM -0400, Matthew L. Creech scratched on the wall: > Hi, > > I have a SQLite database with one large table, and I'd like to shrink > the size of that table to free up space in the filesystem. My problem > is that the database is (for example) 100 MB, and I have