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From <...@covalent.net>
Subject Re: Scoreboard redesign
Date Sun, 20 May 2001 18:49:43 GMT

> > If your concern is one of lost information after the request finishes and
> > is finally cleaned up, then perhaps we need to think about combining the
> > totals up to a higher level before the element is cleaned up.
>
> This is my real concern. After rereading this thread I did not
> discover a solution here. You mention the solution already and this
> is required to provide a real status of the web-server.
> Since the parent can control the elements in the linked list I
> beleive that the parent should indeed grab a the summary at an
> higher level. If this is not done, the server will never provide a
> real status.
>
> Due to the changes in the linked list I believe that the usefullness
> of  access_count and bytes_served in the worker_score is zero.
> Where in the old design only a quick scan over the array would
> have been enough, you now  have to walk thru a linked list.
> And the linked list was introduced to avoid that for instance
> mod_status had to run all the array elements in the scoreboard.
>
> To me this is resulting in zero advantage.
> Do I miss something here??
>
> At least it looks to me that in the alpha 18 the overall
> statistics will get lost after some time.

None of the linked list has been implemented yet, so this can't be an
issue in 2.0.18.

Having said that, the locking issue is a much bigger deal with linked
lists than was mentioned on-list last week.  The child process will have
to walk the list whenever mod_status is called, which means that the child
process will have to lock the scoreboard while serving status requests.

Ryan

_______________________________________________________________________________
Ryan Bloom                        	rbb@apache.org
406 29th St.
San Francisco, CA 94131
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