Tested ab and confirmed terminated requests with reloads during run (complete output pasted at the end).

Failed requests: 180
(Connect: 0, Receive: 24, Length: 78, Exceptions: 78)

ab reports reports terminated connections while receiving. This should not happen at all when executing a reload.

But:
If I run ab without keepalive connections, it is not possible for me to get failed requests by reloading nginx. Maybe the problem is related with persistent connections.

Does your edge nginx use keepalive connections to access the internal nginx?




$ ab -n 1000000 -c 20 -k -r http://localhost/
This is ApacheBench, Version 2.3 <$Revision: 1706008 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 10.10.1.171 (be patient)
Completed 100000 requests
Completed 200000 requests
Completed 300000 requests
Completed 400000 requests
Completed 500000 requests
Completed 600000 requests
Completed 700000 requests
Completed 800000 requests
Completed 900000 requests
Completed 1000000 requests
Finished 1000000 requests


Server Software: nginx
Server Hostname: 127.0.0.1
Server Port: 80

Document Path: /
Document Length: 973 bytes

Concurrency Level: 20
Time taken for tests: 17.916 seconds
Complete requests: 1000000
Failed requests: 180
(Connect: 0, Receive: 24, Length: 78, Exceptions: 78)
Keep-Alive requests: 994974
Total transferred: 1251877604 bytes
HTML transferred: 972924106 bytes
Requests per second: 55815.82 [#/sec] (mean)
Time per request: 0.358 [ms] (mean)
Time per request: 0.018 [ms] (mean, across all concurrent requests)
Transfer rate: 68236.90 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.0 0 3
Processing: 0 0 0.4 0 20
Waiting: 0 0 0.4 0 20
Total: 0 0 0.4 0 20

Percentage of the requests served within a certain time (ms)
50% 0
66% 0
75% 0
80% 0
90% 1
95% 1
98% 1
99% 1
100% 20 (longest request)