Re: HttPrevayler

If this proxy relies on the current Prevayler and waits for a request
to finish then one long request can suspend all the others. It will be
a bottleneck because of the single lock inside Prevayler.

If it does not wait for a request to finish then how those failed
requests are going to be handled?

On Wed, Jun 10, 2009 at 10:07 PM, Klaus
Wuestefeld<[email protected]> wrote:
> Thanks. This is helping a lot. :)
>
> Three kinds os failures:
>
> 1) Garden-variety bugs, broken links, etc. In these cases the web app
> will behave deterministically so we don't have to consider these as
> failures for our purposes.
>
> 2) Non-deterministic OutOfMemory-style catastrophical failures of the
> web app. Every http request must be sent to the web app with a
> sequence number as a parameter. The web app can refuse (reply with a
> specific error) saying: "Sorry, you sent me request 45, I was
> expecting request 42". HttPrevayler then starts re-sending requests
> since 42. So, if the web app crashes (OOM or StackOverflow, for
> example) and is rebooted, we are ok.
>
> 3) Network failures between proxy and web app. Solved the same as 2)
> above, with the request sequence number.
>
> Our only problem is failures which are both non-catastrophic AND
> non-deterministic.
>
> Klaus.
>
>
> On Wed, Jun 10, 2009 at 3:00 PM, Sergey Didenko<[email protected]> wrote:
>> So the web app can be written to be just in memory then.
>> Or just to make occasional snapshots and load the last one on restart.
>>
>> Interesting idea. Though I can't understand right now how practical it is.
>>
>> What about failed requests? Does proxy just journal a request or does
>> it wait to see if the web app fails?
>>
>> ------------------------------------------------------------------------------
>> Crystal Reports - New Free Runtime and 30 Day Trial
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>>
>
> ------------------------------------------------------------------------------
> Crystal Reports - New Free Runtime and 30 Day Trial
> Check out the new simplified licensing option that enables unlimited
> royalty-free distribution of the report engine for externally facing
> server and web deployment.
> http://p.sf.net/sfu/businessobjects
> _______________________________________________
> To unsubscribe go to the end of this page: http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
> _______________________________________________
> "Databases in Memoriam" -- http://www.prevayler.org
>

------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing 
server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
To unsubscribe go to the end of this page: http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
_______________________________________________
"Databases in Memoriam" -- http://www.prevayler.org