On Sep 13, 2007, at 1:45 PM, Patrick K. O'Brien wrote:

>  noticed this phenomenon in situations such as yours, where I had
> created *lots* of objects (like when converting an existing
> FileStorage2 database to ShelfStorage).  What I'd be curious to
> know is how quickly does ShelfStorage startup time degrade in
> between packings?  I'm hoping that the benefits of ShelfStorage
> don't degrade too quickly (like, startup time increasing
> dramatically after only a few transactions without a pack).  Does
> anyone have any insight into this?


When ShelfStorage starts up it reads the file header to locate
the index of objects known at the last pack.  It does not read
any of the records.  It scans through all records since the last
pack, noting the offsets and oids, but not actually loading
any object records.  This is pretty fast, but it is does take
time proportional to the number of object records committed since
the last pack.  If you want to be sure of a fast start, run the
pack (and let it complete) before you stop.