[Stackless] Google Application Engine Thread on Stackless

Jeff Senn senn at maya.com
Fri Mar 27 14:18:30 CET 2009


Well... this:

> Sometimes unavoidable bad things happen and cannot be mitigated.

is a tautology.  Also, not an excuse for exercising good judgement in  
architecture
and design. :-) I know you probably understand that.

I'm not saying "pickling is bad" -- it has it's uses -- perhaps I am
saying there is a dangerous "siren's call" there.... You have to be very
careful in also assessing the costs of using it in a design.   Using  
it as
discussed certainly seems to violate one of the first principles of  
information
systems design -- put simply (and slightly inaccurately):
"keep your data and your program separate" --
so one might assume that it has some high (architectural) costs.

This has hopped sideways into a philosophical design discussion and  
perhaps
doesn't belong on this list (mea cupla...)

-Jas

On Mar 26, 2009, at 8:11 PM, andrewfr_ice at yahoo.com wrote:

>
> Hello Jeff:
>
> [I deleted a half-typed-rant on this subject (and the related, growing
> trend to think "virtualizing solves all my problems") before posting  
> it... on the theory that I was just being old and crotchety....   
> suffice it to say that if you consider what is going to happen the  
> day you have a billion requests pending and you need to switch out  
> you interpreter/hardware/shared-libs/OS/whatever to one
> that can't unpickle them anymore
> because you aren't really sure of their data structure... (or,  
> heaven forbid, there is a subtle bug in your unpickle-and-upgrade  
> code!). well...]
>
> This topic has come up before. I would prefer to actually run tests  
> to see what the problems are? I need to look at pickling more in  
> depth. Maybe it would help if I read up on hot-swapping. I wonder if  
> modulisation/layering and having an interpreter dampen the effects  
> of a change?
>
> Currently my approach would be simple. Do a sanity check on the  
> pickled programme. If you can't properly depickle and continue,  
> either the old application or the new application, wakes up the  
> tasklets, tells them something bad has happened, clean-up and  
> terminate. Sometimes unavoidable bad things happen and cannot be  
> mitigated.
>
> Cheers,
> Andrew
>
>
>
>
>
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