On 12/29/2014 17:19, Eric Covener wrote:
>I have a question about the situation that happens with Apache with >Wikimedia app. >In short, Apache begins to break connections when there are many concurrent >requests. >(Here is the bug report that I created for wikipedia >https://phabricator.wikimedia.org/T85191). >Connections are broken after http request is complete, but 'Connection: >keep-alive' has been set by the server in the last response. > The event MPM does this as a specific process runs out of threads, in the hope that there are other processes in better shape. If it didn't, and the keepalive connections became ready, they would queue.
I run only 30 requests concurrently, and every ~15-25 sec an event occurs when many connections are dropped. 30 must be a drop in a bucket for the powerful wikipedia server, which probably serves thousands of requests concurrently.
So it is not clear why 30 concurrent users can cause it run out of threads, and why connections are broken in bulk, many of them at the same time. And why congestion is triggered later, after 15 seconds of successful work (assuming the problem is congestion that triggers some logic in apache server)?
Since 30 must be very little compared to how many requests it serves in general, does this mean that it stops every 15 seconds and just sheds connections randomly?
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