[Seaside] Are Collections threadsafe?

Malte Zacharias malte.zacharias at nordakademie.de
Tue Feb 26 02:05:52 UTC 2008

Thanks to all of you for the numerous replies, I have read a fair bit of 
the referenced discussion and certainly hope it will be a non-issue for 
me, I kind of expected the one major mechanism for process 
synchronisation to "just work", just as the mayority of people I 
suppose. Strange thing is, that immediately after starting to work with 
Mutex and Delays my image got wrecked.. Wrecked as in UI unbearable 
slow, mouse clicks only got noticed after lots of time, etc.. Mind you 
the seaside application did not show those effects. and the Process 
browser only showed that the UI process consumed an awful lot of time.. 
I hope not to experience the same with the actual image running the 
server. (fortunately the Data is also stored externally now, thanks to 
Ramon Leons description of a simple ReferenceStream based Persistence) 
Sad that I can't be certain whether it was just a strange coincidence..

> So saying that these things are "broken" is an overstatement. :) Sure,
> we have discovered some issues - but we are talking things that have
> gone undetected a loooong time.
Well, concurrency tends to alway shoots you in the back when you expect 
it the least.. And how many people would have done like I did; thinking 
Image's broken, let's use a fresh one. Sad, loosing all the 
customizations though..

> IMHO - while you can learn something from digging into these discussions
> and patches, you could also just move along and use a Monitor (or
> Semaphore - but a Monitor is probably "smarter") and be done with it.
Just FYI I am using Mutexes right now. I wasn't expecting lots of 
problems anyway, we only have very few concurrent user (averaged to 
below 1 I'd guess..) with the occasional spikes, so it's more a better 
safe than sorry approach.

Big thanks,
Malte Zacharias

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