[ZODB-Dev] Pack problem

[Simone Deponti]

Hi Jim,

On Mon, Jun 30, 2014 at 12:43 PM, Jim Fulton <jim at zope.com> wrote:

> As the comment suggests, if you continued packing, the new file
> would be as large as the old one, because no records would be
> removed.  This is likely either because a) you've already packed to
> that pack time before, or b) None of the objects written up to the pack time
> have been written after the pack time and this there are no old records
> to be removed.

Therefore, if I get it right, what happens is:

* All transactions prior to the packing time are scanned to see if
they contain reachable data, if they do, they are kept. Therefore the
condition there checks that, if we have reached the pack time (after
which, all transactions are copied over anyway) and none has been
detected as "deletable", then it doesn't make sense to go on packing.

* If pack-gc is on, then all the transaction prior to pack time that
have been kept are purged of unreachable objects

Is that correct?

-- 
Simone Deponti