This reduces the number of file entries we carry in the database,
sometimes significantly. The downside is that if a file is deleted while
a device is offline, and that device comes back more than the cutoff
interval (six months) later, those files will get resurrected at some
point.
The current limit is far too low for our workloads. Perhaps we should
aim even higher than the 64MiB this patch proposes?
Citing the sqlite docs:
> [...] after committing a transaction the rollback journal file may
remain in the file-system. **This increases performance for subsequent
transactions since overwriting an existing file is faster than append to
a file**, but it also consumes file-system space.
tl;dr: if the limit is too low, we're shooting ourselves in the foot in
terms of performance.
Switch the database from LevelDB to SQLite, for greater stability and
simpler code.
Co-authored-by: Tommy van der Vorst <tommy@pixelspark.nl>
Co-authored-by: bt90 <btom1990@googlemail.com>
