[Zope] PCGI Error explanation (Second Request)

Stuart Nicholson stuart.nicholson@wirelessdatanz.com
Wed, 23 Jan 2002 08:45:27 +1300


In my (limited!) Zope experience under WinNT and IIS/PCGI I've found that the 'Temporarily Unavailable' error is caused typically by timeouts. If you look at the PCGI code this
'error page' is returned if PCGI fails to receive a response from Zope in a timely manner. I've seen this error because:

- The back end Zope server has crashed! This one is pretty obvious :).

- The page requested is built using fields extracted from a database and the database is offline (the PCGI timeout is shorter than the database connection timeout).

- The back end Zope server is heavily loaded (PCGI times out before a page is returned from Zope).

- The page requested is built using a long running database query that fails to complete before the PCGI timeout takes effect.

- Your database queries have caused a database 'deadlock' (this can happen quite easily using SQL server and the transaction management in Zope) and PCGI times out. Check your
database 'active processes' and 'lock' tables/information.

Hope that helps?

Stuart Nicholson
Software Engineer
wirelessdata - making data fly

-----Original Message-----
From: Dieter Maurer [mailto:dieter@handshake.de]
Sent: Wednesday, 23 January 2002 8:13 AM
To: sgrimes@acceleratedtechnology.com
Cc: Zope
Subject: Re: [Zope] PCGI Error explanation (Second Request)


Steven Grimes writes:
 > I don't want to be a pest but our system is randomly giving the "Temporarily
 > Unavailable" error message to clients and I don't know what is causing it.
 > If I can't get an explanation of these error messages I'm afraid my boss
 > will make me move away from using Zope. So please someone give me some help.
The best thing you can do it to look at the PCGI wrapper source
and search for the error messages you want an explanation for...


Dieter

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