[Seaside] Apache frontend for Squeak, mod_scgi ?
renggli at student.unibe.ch
Sat Sep 27 00:50:30 CEST 2003
>> This post by Lukas Renggli also gave me pause for concern.
>> I hope he got that problem resolved, if so it wasn't mentioned on the
>> list to my memory.
> The problem was resolved. IIUC it didn't turn out to be a problem
> with Squeak itself, but rather with a tricky race condition in the
> application code.
> Lukas, is that correct?
The last week has been very calm, we didn't get error-messages anymore
and the application itself run smoothly. However we had some crashes of
the VM ...
So let me start at the very beginning: First of all, I set the VM
parameter -notimer and at first it seemed to help a lot, but on the
long run the problem didn't disappear.
Last weekend we could take the server in our office, as they were
changing something at the customers site and the network would have
been down anyway. So I had full access to that machine for the first
time and I even managed to write some stress-tests that showed a
problem. Well, we are not sure if this was the same problem as on the
server, but it was a severe problem. So I rewrote the complete
persistence-mechanism of our application and carefully protected any
write-access to postgres with critical sections. The stress-test did
run then and up-to-now we haven't seen our socket problem anymore.
Well, but there is still that strange feeling not knowing what the
problem actually was. Very probably Avi is right and it was some
race-condition in our application code. Or it could have been the buggy
SharedQueue that we are using to pool our postgres-sockets. I was
shocked when reading Nathanael's mail about those synchronisation bugs
in it. Why is something like this in the base-image?
To come back to the original post, we never had problems with the
sockets of the http-connections. We are using Seaside with Comanche 5.1
behind Apache as https-proxy. Apache is also used to serve static
content, like html pages, style-sheets and images. We are using this
combination of Comanche 5.1 and Apache also in other projects and even
on different platforms, like Linux, Windows and Mac. The speed had
never been a problem, so we didn't felt the need to have something like
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