On 7 Dec 2000, at 9:41, Diego Rodrigo Neufert wrote:
> Transaction Error too....
> Are you trying to do session management and/or database querys in two
> different frames?
Thanks to everyone who emailed me about transaction errors, here's
what was happening so you can avoid it too.
First, we're using Interbase on Linux. Apparently there's a bug in the
Linux Interbase client that causes the client connection to dropped if no
DB requests are made within .. (5 minutes?)
There's a fix in gvibDA that works around this by generating a dummy
select before any query() is executed. If an exception is raised in the
dummy select, the db-api connection is deleted and a new one opened.
This fix seems to work pretty well.
But I'm also using a gvib db-api connection from within Python code
called through external methods. This second connection is used with
SQLDict. I've wrapped it up with THUNK Zope code so SQLDict can
participate in Zope's transaction machinery.
Unfortunately I did not have the Linux-broken-pipe-fix in my SQLDict
code, so that second connection could fail.
The second connection is only activated when a person selects
"Checkout". SQLDict registers itself with the transaction manager, then
creates a cursor and executes an sql request.
This causes an exception to be raised (broken pipe). The Zope
transaction manager does a rollback, which causes this second
interbase connection to try to call rollback(), which raises another
broken pipe exception.
This second exception within the transaction rollback causes a system-
wide failure and Zope disables all further transactions, which then kills
the entire site.
The solution was to add the broken-pipe handling code to the external
method before making calls into SQLDict.
Unfortunately my first fix was wrong, so it didn't work, but I think I have it
This brings up a good issue. How do you work on a live Zope site
without causing serious problems? Versions only go just so far.
Fortunately, because I'm using SQLSession to hold the shopping cart
contents, I can restart Zope at any time without killing off active
Hopefully there will be a fix for this interbase client bug from the firebird
Brad Clements, [EMAIL PROTECTED] (315)268-1000
http://www.murkworks.com (315)268-9812 Fax
netmeeting: ils://ils.murkworks.com AOL-IM: BKClements
Zope maillist - [EMAIL PROTECTED]
** No cross posts or HTML encoding! **
(Related lists -