Saga continues ([Zope-DB] DCOracle2: close connection doesn't)

Dieter Maurer dieter at
Thu Oct 2 18:16:45 EDT 2003

Dario Lopez-Kästen wrote at 2003-10-2 11:42 +0200:
 > actually, what no app will protect you from is bad sql. What Zope should
 > protect us from is dropped connections for long running SQL-executes.

Zope is *not* dropping connecetions for long running queries, unless
you press the "minimize" button in "Control_Panel --> Database management
--> Flush cache".

 > ....
 > I can live with Zope waiting for the DB to respond. What I cannot live with
 > is Zope waiting for a response on a connection that was dropped for some
 > unknown reason.

Zope does not drop the connection and it reexecutes the query or
raises an exception when it notices that the connection has been

However, we (e.g.) use a firewall that drops connections (after a configurable
timeout) in a way that the endpoints do not recognize this.
It's a bug in the firewall. The endpoints are not to blame.
In our case, Zope can cope with this problem as sending new
data over the dropped connection fails (and leads to reconnection)
as we do not use queries that take longer than the 30 min timeout.
However, the database server never detects that it waits for
data from a cut connection. We have to restart the server
regularly to get rid of the piling up defunct sessions.


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