[ZODB-Dev] Very slow restarts with ZEO 2 ...

[Shane Hathaway]

Joachim Werner wrote:
> Hi!
> 
> I've switched a two-server ZEO installation to ZEO 2 and now I have the
> following "problem":
> 
> While the ZEO clients had started up and restarted almost immediately (5-10
> secs maximum for a start without having to rebuild the cache files), ZEO 2
> clients take up to half a minute.
> 
> This is not a problem for the production servers, as they usually won't
> restart frequently. But for development this is not so nice. My first guess
> was that ZEO 2 does some consistency checks on the cache files or so, as it
> spends a considerable amount of time after connecting to the ZEO server,
> which still happens almost instantly.

In development, it is likely that you don't want to use persistent 
caches.  Persistent caches retain the contents of the cache between 
runs, often requiring verification of the entire contents of the cache 
upon restart.  You can disable persistent caches by not specifying 
anything in the "client" argument to the ClientStorage constructor, and 
not setting the ZEO_CLIENT environment variable.  (This is quite 
non-intuitive, but it works.)

Debugging problems of this nature is easier, BTW, if you set the 
environment variable STUPID_LOG_SEVERITY=-100 on both the storage server 
and the ZEO client.  At some point this variable will be renamed 
EVENT_LOG_SEVERITY, if it hasn't already. :-)

Shane