I don't know the implementation details, but in the extreme scenario
you  described, where number of threads is set to 100, but only 1 is
active, because there is only 1 host to crawl, there is not much you
can do - you don't want more than 1 thread hitting the same host.

Are you saying the current implementation results in sleeping threads,
when in fact they could be fetching pages?

Otis

--- Stefan Groschupf <[EMAIL PROTECTED]> wrote:

> Hi developers.
> 
> I would love to discuss the thread management of the fetcher, may be 
> there is room for improvements.
> The fetcher start as much threads as setuped in the configuration
> file 
> for example 100 threads.
> The problem that i see is that in case the fetchlist contains many
> urls 
> of the same host a set of threads sleep and is not used to fetch.
> Or do I oversee something in the code?
> So in case we start n threads and actually m threads sleep since the 
> host is blocked there are only n-m thread working.
> 
> Wouldn't it be better to have every-time n threads working?
> I see 2 possible solutions to solve that problem:
> 
> 1.) We change the way we handle delayed urls. For example write
> blocked 
> urls back to a queue and the thread try the next url.
> 2.) We monitor and handle the number of threads actually working. For
> 
> example a thread that starts to sleep announce that to a handler. The
> 
> handler could start a new thread for the time the other thread is 
> sleeping.
> 
> I personal think the first solution would be better however this 
> require some more detailed technical discussion.
> 
> Any comments?
> 
> Greetings,
> Stefan
> 
> 
> 
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