mirror/nginx
1
0
Fork 0
mirror of https://github.com/nginx/nginx.git synced 2025-06-11 04:12:40 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Better recheck of dead upstream servers.

Browse Source 
Previously nginx used to mark backend again as live as soon as fail_timeout
passes (10s by default) since last failure.  On the other hand, detecting
dead backend takes up to 60s (proxy_connect_timeout) in typical situation
"backend is down and doesn't respond to any packets".  This resulted in
suboptimal behaviour in the above situation (up to 23% of requests were
directed to dead backend with default settings).

More detailed description of the problem may be found here (in Russian):
http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html

Fix is to only allow one request after fail_timeout passes, and
mark backend as "live" only if this request succeeds.

Note that with new code backend will not be marked "live" unless "check"
request is completed, and this may take a while in some specific workloads
(e.g. streaming).  This is believed to be acceptable.
This commit is contained in:
Maxim Dounin 2011-10-12 14:22:48 +00:00
parent 72df0f400a
commit b713e480ca
3 changed files with 18 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/http/modules/ngx_http_upstream_ip_hash_module.c
View File

@ -185,8 +185,8 @@ ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
break;
}
if (now - peer->accessed > peer->fail_timeout) {
peer->fails = 0;
if (now - peer->checked > peer->fail_timeout) {
peer->checked = now;
break;
}
}

21
src/http/ngx_http_upstream_round_robin.c
View File

@ -443,8 +443,8 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
break;
}
if (now - peer->accessed > peer->fail_timeout) {
peer->fails = 0;
if (now - peer->checked > peer->fail_timeout) {
peer->checked = now;
break;
}
@ -491,8 +491,8 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
break;
}
if (now - peer->accessed > peer->fail_timeout) {
peer->fails = 0;
if (now - peer->checked > peer->fail_timeout) {
peer->checked = now;
break;
}
@ -663,15 +663,16 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
return;
}
peer = &rrp->peers->peer[rrp->current];
if (state & NGX_PEER_FAILED) {
now = ngx_time();
peer = &rrp->peers->peer[rrp->current];
/* ngx_lock_mutex(rrp->peers->mutex); */
peer->fails++;
peer->accessed = now;
peer->checked = now;
if (peer->max_fails) {
peer->current_weight -= peer->weight / peer->max_fails;
@ -686,6 +687,14 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
}
/* ngx_unlock_mutex(rrp->peers->mutex); */
} else {
/* mark peer live if check passed */
if (peer->accessed < peer->checked) {
peer->fails = 0;
}
}
rrp->current++;

1
src/http/ngx_http_upstream_round_robin.h
View File

@ -23,6 +23,7 @@ typedef struct {
ngx_uint_t fails;
time_t accessed;
time_t checked;
ngx_uint_t max_fails;
time_t fail_timeout;