[Zope] Zope 2.8.4 strange behavior
Chris McDonough
chrism at plope.com
Sun Nov 27 20:50:42 EST 2005
On Nov 27, 2005, at 8:13 PM, Dennis Allison wrote:
> here to begin to track this one down. The failure
> is spontaneous and apparently not triggered by any readily
> distinguishable
> inputs or pattern of inputs. The behavior smells a bit of resource
> limits
> or process synchronization problems, but there is not real evidence
> for
> either being the root cause. I am not sure what monitoring I
> should be
> doing to help locate the source of the problem.
>
> Has anyone seen seen a similar problem? Any advice as to how to
> proceed?
A pool of database connections is kept around to pull from for each
ZODB database you have. By default, there are 7 of them per
database; this number can be changed by the pool-size parameter in
the <zodb_db> section in your config file. These connections are
returned to the pool when a connection is closed. This usually
happens when a transaction that is using that connection completes.
The symptom you're describing has happened to me in the past. Zope
stops serving requests and my CPU is not pegged (it's not hitting the
CPU hard via an infinept loop I've made). I usually end up tracking
it down to the fact that my instance is somehow leaking database
connections. The connection is never closed so it never gets
returned to the pool. This can happen when there is an error during
a transaction commit or abort.
Since you've previously posted to the list with commit errors of just
this kind, it seems like that would be the logical place to start.
You didn't mention seeing any of these errors, though, so if you
don't see any of those in the event log, I'm not sure where to go
from there other than debugging by binary exclusion which can be
impossible when the failures happen so far apart. :-(
- C
More information about the Zope
mailing list