Connections lost when server restarts

[Patrick Dobbs]

Hello,

I'm using ClientStorage in a long running, single threaded application.
It seems to make sense for the Connection object to be long lived so it
can do caching goodness. However, if the server is restarted then the
connection is broken and an exception is raised. Since this can occur on
read as well as write operations the only solution I can see is to wrap
the entire application in a try/except. This seems clumsy.

I'm sure this is an issue which is addressed in QPy and other
applications, and I was wondering if someone could suggest a good solution.

Thanks

Patrick

[Binger David]

Post by Patrick Dobbs
Hello,
I'm using ClientStorage in a long running, single threaded
application. It seems to make sense for the Connection object to be
long lived so it can do caching goodness. However, if the server is
restarted then the connection is broken and an exception is raised.
Since this can occur on read as well as write operations the only
solution I can see is to wrap the entire application in a try/
except. This seems clumsy.

The ClientStorage can't really pick up where it left off with a new
server connection. The
old server, just before terminating, might have been holding
invalidations that have not
yet been delivered to your client. Once the server terminates, the
record of these pending
invalidations is lost, and the new server has no way of knowing what
the client is
holding that is out of date. There is a similar problem with oid
allocation.

Post by Patrick Dobbs
I'm sure this is an issue which is addressed in QPy and other
applications, and I was wondering if someone could suggest a good solution.

In QP, the control program, "qp" always restarts the clients when it
restarts the Durus server.
Unless we are updating the Durus code, we usually just leave the Durus
server running
when we updating the code for an application.

In your long running application, maybe you could use a FileStorage
directly.
That's better if you don't happen to need to support multiple clients.