Mercurial > hg > nginx-quic
annotate src/core/ngx_resolver.h @ 4207:4fc91bae6f83
Better recheck of dead upstream servers.
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.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2011 14:22:48 +0000 |
parents | 71193a456616 |
children | 016352c19049 4919fb357a5d |
rev | line source |
---|---|
1649 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4 */ | |
5 | |
6 | |
7 #include <ngx_config.h> | |
8 #include <ngx_core.h> | |
9 | |
10 | |
11 #ifndef _NGX_RESOLVER_H_INCLUDED_ | |
12 #define _NGX_RESOLVER_H_INCLUDED_ | |
13 | |
14 | |
15 #define NGX_RESOLVE_A 1 | |
16 #define NGX_RESOLVE_CNAME 5 | |
17 #define NGX_RESOLVE_PTR 12 | |
18 #define NGX_RESOLVE_MX 15 | |
19 #define NGX_RESOLVE_TXT 16 | |
1965 | 20 #define NGX_RESOLVE_DNAME 39 |
1649 | 21 |
22 #define NGX_RESOLVE_FORMERR 1 | |
23 #define NGX_RESOLVE_SERVFAIL 2 | |
24 #define NGX_RESOLVE_NXDOMAIN 3 | |
25 #define NGX_RESOLVE_NOTIMP 4 | |
26 #define NGX_RESOLVE_REFUSED 5 | |
27 #define NGX_RESOLVE_TIMEDOUT NGX_ETIMEDOUT | |
28 | |
29 | |
1683
1e0b028055ec
allow to use IP addresses without defined resolver
Igor Sysoev <igor@sysoev.ru>
parents:
1649
diff
changeset
|
30 #define NGX_NO_RESOLVER (void *) -1 |
1e0b028055ec
allow to use IP addresses without defined resolver
Igor Sysoev <igor@sysoev.ru>
parents:
1649
diff
changeset
|
31 |
1969 | 32 #define NGX_RESOLVER_MAX_RECURSION 50 |
33 | |
1683
1e0b028055ec
allow to use IP addresses without defined resolver
Igor Sysoev <igor@sysoev.ru>
parents:
1649
diff
changeset
|
34 |
1649 | 35 typedef struct { |
36 ngx_connection_t *connection; | |
37 struct sockaddr *sockaddr; | |
38 socklen_t socklen; | |
39 ngx_str_t server; | |
3408
71193a456616
add context to a resolver log
Igor Sysoev <igor@sysoev.ru>
parents:
3269
diff
changeset
|
40 ngx_log_t log; |
1649 | 41 } ngx_udp_connection_t; |
42 | |
43 | |
44 typedef struct ngx_resolver_ctx_s ngx_resolver_ctx_t; | |
45 | |
46 typedef void (*ngx_resolver_handler_pt)(ngx_resolver_ctx_t *ctx); | |
47 | |
48 | |
49 typedef struct { | |
50 ngx_rbtree_node_t node; | |
51 ngx_queue_t queue; | |
52 | |
53 /* PTR: resolved name, A: name to resolve */ | |
54 u_char *name; | |
55 | |
56 u_short nlen; | |
57 u_short qlen; | |
58 | |
59 u_char *query; | |
60 | |
61 union { | |
62 in_addr_t addr; | |
63 in_addr_t *addrs; | |
64 u_char *cname; | |
65 } u; | |
66 | |
67 u_short naddrs; | |
68 u_short cnlen; | |
69 | |
70 time_t expire; | |
71 time_t valid; | |
72 | |
73 ngx_resolver_ctx_t *waiting; | |
74 } ngx_resolver_node_t; | |
75 | |
76 | |
77 typedef struct { | |
78 /* has to be pointer because of "incomplete type" */ | |
79 ngx_event_t *event; | |
80 | |
81 /* TODO: DNS peers balancer */ | |
82 /* STUB */ | |
83 ngx_udp_connection_t *udp_connection; | |
84 | |
85 ngx_log_t *log; | |
86 | |
87 /* ident must be after 3 pointers */ | |
88 ngx_int_t ident; | |
89 | |
90 ngx_rbtree_t name_rbtree; | |
91 ngx_rbtree_node_t name_sentinel; | |
92 | |
93 ngx_rbtree_t addr_rbtree; | |
94 ngx_rbtree_node_t addr_sentinel; | |
95 | |
96 ngx_queue_t name_resend_queue; | |
97 ngx_queue_t addr_resend_queue; | |
98 | |
99 ngx_queue_t name_expire_queue; | |
100 ngx_queue_t addr_expire_queue; | |
101 | |
102 time_t resend_timeout; | |
103 time_t expire; | |
104 time_t valid; | |
105 | |
106 ngx_uint_t log_level; | |
107 } ngx_resolver_t; | |
108 | |
109 | |
110 struct ngx_resolver_ctx_s { | |
111 ngx_resolver_ctx_t *next; | |
112 ngx_resolver_t *resolver; | |
113 ngx_udp_connection_t *udp_connection; | |
114 | |
115 /* ident must be after 3 pointers */ | |
116 ngx_int_t ident; | |
117 | |
118 ngx_int_t state; | |
119 ngx_int_t type; | |
120 ngx_str_t name; | |
121 | |
122 ngx_uint_t naddrs; | |
123 in_addr_t *addrs; | |
124 in_addr_t addr; | |
125 | |
126 /* TODO: DNS peers balancer ctx */ | |
127 | |
128 ngx_resolver_handler_pt handler; | |
129 void *data; | |
130 ngx_msec_t timeout; | |
131 | |
132 ngx_uint_t quick; /* unsigned quick:1; */ | |
1969 | 133 ngx_uint_t recursion; |
1649 | 134 ngx_event_t *event; |
135 }; | |
136 | |
137 | |
3269
f0d596e84634
rename ngx_peer_addr_t to ngx_addr_t
Igor Sysoev <igor@sysoev.ru>
parents:
1969
diff
changeset
|
138 ngx_resolver_t *ngx_resolver_create(ngx_conf_t *cf, ngx_addr_t *addr); |
1649 | 139 ngx_resolver_ctx_t *ngx_resolve_start(ngx_resolver_t *r, |
140 ngx_resolver_ctx_t *temp); | |
141 ngx_int_t ngx_resolve_name(ngx_resolver_ctx_t *ctx); | |
142 void ngx_resolve_name_done(ngx_resolver_ctx_t *ctx); | |
143 ngx_int_t ngx_resolve_addr(ngx_resolver_ctx_t *ctx); | |
144 void ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx); | |
145 char *ngx_resolver_strerror(ngx_int_t err); | |
146 | |
147 | |
148 #endif /* _NGX_RESOLVER_H_INCLUDED_ */ |