[Zope-dev] DB.close() needs to be called
Chris McDonough
chrism@zope.com
13 Nov 2002 11:01:14 -0500
Maybe normal shutdown should manually call the shutdown signal handler
function and normal restart should manually call the restart signal
handler function?
On Wed, 2002-11-13 at 10:28, Toby Dickenson wrote:
> On Wednesday 13 November 2002 2:10 pm, Barry A. Warsaw wrote:
> > >>>>> "TD" == Toby Dickenson <tdickenson@geminidataloggers.com> writes:
> > >> This is a bad thing for the Berkeley storages because their
> > >> .close() must get called or you'll end up with corrupt
> > >> databases or worse <wink>.
> >
> > TD> How much of that paragraph is covered by the wink?
> >
> > The "or worse" part. If you've enable autopacking and you don't
> > cleanly close the storage, you won't exit the process because the
> > autopack thread won't get stopped and joined.
>
> Yes, I had the same problem with DirectoryStorage, which uses a seperate
> thread to move writes from its journal directory into the database directory.
>
> > We could make the
> > autopack thread a daemon process
>
> Thats how DirectoryStorage now works.
>
> > It wouldn't be good, but remember that we run BerkeleyDB in
> > auto-recovery mode, so it means that the next time you open the
> > database, it will run recovery (you can also run recovery manually).
> > However, depending on your checkpointing policy, and the size of
> > committed data since your last checkpoint, recovery could end up
> > taking a long time.
>
> Last time I looked at your BerkeleyDB storages, the administrator needed to
> implement his own checkpointing policy. I always thought that was a
> disadvantage. Would it now be a good idea for the storages to trigger their
> own checkpointing inside the autopacker thread?
>
> > Sure, any number of bad things can happen at any time, and defense
> > against that is one of the benefits of using BerkeleyDB underneath.
> > But under normal operations, we definitely want to exit cleanly.
>
> Agreed, on both points.
>
>
>
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