lost some request while DNS resolving

[HatsuneMiku3939]

reported from #1

ngx_http_upstream_resolveMK_get_peer fitting early resolved values into peer (before RESOLVE_STATS_DONE). Near one second, but happens time-to-time and in result 0.05% of requests going to black hole. It's a lot.

2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: resolve_start ok for "home-docker.mcbyte.net"
2017/03/13 20:08:12 [debug] 23470#0: resolve: "home-docker.mcbyte.net"
2017/03/13 20:08:12 [debug] 23470#0: resolve: "_php-fpm-main-9000._tcp.home-docker.mcbyte.net" SRV 39707
2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: resolved_num=1
2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: upstream to DNS peer (192.168.1.11:0)
2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: resolving
2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: resolved_num=1
2017/03/13 20:08:12 [debug] 23470#0: *1 upstream_resolveMK: upstream to DNS peer (192.168.1.11:0)

resolving not finished, but now peer have wrong value "192.168.1.11:0, 192.168.1.11:0" (as one peer) and all request failed

2017/03/13 20:08:12 [debug] 23470#0: resolver DNS response 39707 fl:8580 1/1/0/1
2017/03/13 20:08:12 [debug] 23470#0: resolver DNS response qt:33 cl:1
2017/03/13 20:08:12 [debug] 23470#0: resolver qs:_php-fpm-main-9000._tcp.home-docker.mcbyte.net
2017/03/13 20:08:12 [debug] 23470#0: resolver nsrvs:1 cname:0000000000000000 ttl:68
2017/03/13 20:08:12 [debug] 23470#0: resolve: "620009deb596._php-fpm-main-9000._tcp.home-docker.mcbyte.net"
2017/03/13 20:08:12 [debug] 23470#0: resolve: "620009deb596._php-fpm-main-9000._tcp.home-docker.mcbyte.net" A 55296
2017/03/13 20:08:12 [debug] 23470#0: resolver DNS response 55296 fl:8580 1/1/0/0
2017/03/13 20:08:12 [debug] 23470#0: resolver DNS response qt:1 cl:1
2017/03/13 20:08:12 [debug] 23470#0: resolver qs:620009deb596._php-fpm-main-9000._tcp.home-docker.mcbyte.net
2017/03/13 20:08:12 [debug] 23470#0: resolver naddrs:1 cname:0000000000000000 ttl:68
2017/03/13 20:08:12 [debug] 23470#0: resolve name done: 0
2017/03/13 20:08:12 [debug] 23470#0: resolver expire
2017/03/13 20:08:12 [debug] 23470#0: upstream_resolveMK: "home-docker.mcbyte.net" resolved state(0: Unknown error)
2017/03/13 20:08:12 [debug] 23470#0: resolve name done: 0
2017/03/13 20:08:12 [debug] 23470#0: resolver expire
2017/03/13 20:08:13 [debug] 23470#0: *1 upstream_resolveMK: update from DNS cache
2017/03/13 20:08:13 [debug] 23470#0: *1 upstream_resolveMK: resolved_num=1
2017/03/13 20:08:13 [debug] 23470#0: *1 upstream_resolveMK: upstream to DNS peer (192.168.1.11:9002)

resolving finished, now peer is "192.168.1.11:9002"