[Zope-dev] Communication between Zserver and ZPublisher

[Shane Hathaway]

Alexander Schad wrote:
> Hi all,
> I'd like to understand how the communication between the ZServer and the 
> ZODB
> works. As far as i know the ZServer (Web server) talks to the ZPublisher 
> (ORB)
> to get the Requested Object. But do they communicate via tcpip sockets 
> or unix sockets?
> I have a problem with hanging connections (for more than 10000s) on the 
> debug
> screen in zopes control panel and when all connections are jammed zope 
> freezes.
> I need to  find out where the connections gets stuck and why there is no 
> timeout
> (i even tried to hack in the timeoutsocket module without any effect).
> I think i need to debug this on the os level to find out what these 
> blocked connections are
> doing. But since i'm no unix system administrator i really don't know 
> where i should
> start my investigation.

ZServer, ZPublisher, and ZODB talk to each other through Python objects 
rather than OS-level mechanisms.  Sockets are only involved if you 
introduce ZEO into the mix.

There is a maximum of 7 connections open at a time.  If Zope leaks 
connections, Zope will hang the way you describe once 7 connections have 
been leaked.  Running into this is quite unlikely unless you are writing 
Zope products or are using products that do the wrong thing with 
database connections.  What products are you using?  What version of 
Zope?  What OS?

Shane