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Subject Re: [PATCH] tracking active request phase
Date Sat, 26 Feb 2005 21:32:22 GMT
+1 from me for the general idea. This could be be very helpful for
administrators/operators to trace problems of hung requests. As this
creates more overhead to the request processing (although I think not too
much for me personally) there should be a directive for turning this on/off
like ExtendedStatus. In a second step it would be great to see this implemented
in a more extensible way such that modules would be able to add their own
phases to this list. e.g there could be an API call like ap_add_phase which would
add a string to the phase_names array during the configuration phase of a modul
and would return the index in the array for later use in the AP_SET_REQUEST_PHASE
macro via the module.



Jeff Trawick wrote:
> Normally, processing of a request proceeds quite normally towards
> completion.  Dependencies on external input however can impact normal
> processing enough that requests can be hung.  (connections to LDAP
> server timing out?  somebody decided to play with the database in the
> middle of the day and remote application requests are stalled?)  Add
> to that a loop here and there and it gets more exciting.  Having a
> clue about the phase where a request is stalled (looping) can
> drastically speed up resolution of the problem.  Stalling in access
> checking vs. stalling while waiting for a remote application to
> generate the response have quite different causes and often have to be
> diagnosed by two different support teams/vendors (which themselves may
> be different from the web server support team/vendor).
> By tracking the active request phase, it can be displayed by
> mod_status and can provide a quick guide to where work is piling up,
> since 'W' doesn't help much when some of the phases covered by 'W' are
> much more fragile than anything Apache does.

[..deleted more details..]

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