[Toadling]

This is pure conjecture on my part. I have no inside information and things are probably more complex than I'm portraying here, but here goes anyway:

It seems that as items are added to the OF database, individual XML files for each item are created in your OmniFocus.ofocus bundle. My guess is that each file requires a certain amount of disk space overhead, so collectively they can take up a fair amount of room. When the OF database is rebuilt, all the individual files are coalesced into a single, larger XML file (presumably, the SQLite index is also updated). So the overhead cost is reduced to that of only one file.

[ptone]

I think it is less about file allocation size and more that a file is created for each transaction (change) you make. So if you add an item, then complete it - that's two files created. Uncheck it again, another file, etc...

You could see why this would help if you actually wanted a time machine interface within OF.

-P

[Brian]

The last two posts pretty much sum up what's going on here. OmniFocus writes a file for every change you make to your database. (This is a good thing.)

Deleting items actually causes the database to get bigger, because that's just another change we keep track of. The database is sort of like those Family Circus sunday cartoons. You see the start, then a whole bunch of steps that take you all over the place, finally leading to some end.

Once you rebuild the database, all those changes get collapsed down into the final state you end up with. All the intermediary steps are what's deleted. You lose the "I was at A, then I went to B, and then I went to C."; instead, you just get "I'm at C."

[Lightstorm]

I just archived back to 7/1, and rebuilt my database. Then I did a backup. My backup is STILL 5.9MB. It briefly went to 1MB, then changed in finder to 5.9 again.

Really makes syncing slow on the iPhone. I don't have any large attachments in the notes fields, either.

[CatOne]

Lightstorm, see the other thread on large OF database. It's likely you're synching across multiple computers or devices and something's out of whack. There's a way to fix it; read the other thread.

[Andrew]

Lightstorm, the thread that CatOne is referring to is here:

http://forums.omnigroup.com/showthre...?t=8681&page=2

That links to page 2 of the thread - scroll down until you find the post from Lizard, and see if the instructions within are something you are comfortable trying.