[nginx] Upstream keepalive: clean read delayed flag in stored connections.

[Roman Arutyunyan]

details:   http://hg.nginx.org/nginx/rev/1cb92a2d672e
branches:  
changeset: 7165:1cb92a2d672e
user:      Roman Arutyunyan <arut at nginx.com>
date:      Tue Nov 28 14:00:00 2017 +0300
description:
Upstream keepalive: clean read delayed flag in stored connections.

If a connection with the read delayed flag set was stored in the keepalive
cache, and after picking it from the cache a read timer was set on that
connection, this timer was considered a delay timer rather than a socket read
event timer as expected.  The latter timeout is usually much longer than the
former, which caused a significant delay in request processing.

The issue manifested itself with proxy_limit_rate and upstream keepalive
enabled and exists since 973ee2276300 (1.7.7) when proxy_limit_rate was
introduced.

diffstat:

 src/http/modules/ngx_http_upstream_keepalive_module.c |  1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diffs (11 lines):

diff -r 044cb349fd3c -r 1cb92a2d672e src/http/modules/ngx_http_upstream_keepalive_module.c
--- a/src/http/modules/ngx_http_upstream_keepalive_module.c	Mon Dec 04 17:30:02 2017 +0300
+++ b/src/http/modules/ngx_http_upstream_keepalive_module.c	Tue Nov 28 14:00:00 2017 +0300
@@ -340,6 +340,7 @@ ngx_http_upstream_free_keepalive_peer(ng
     pc->connection = NULL;
 
     if (c->read->timer_set) {
+        c->read->delayed = 0;
         ngx_del_timer(c->read);
     }
     if (c->write->timer_set) {