Mercurial > hg > nginx-quic
view src/mysql/ngx_http_mysql_test.c @ 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 | f0d596e84634 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_mysql.h> #include <ngx_http.h> typedef struct { ngx_addr_t *peers; ngx_uint_t npeers; } ngx_http_mysql_test_conf_t; static void ngx_http_mysql_auth(ngx_mysql_t *m); static void ngx_http_mysql_done(ngx_mysql_t *m); static void *ngx_http_mysql_test_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_mysql_test(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_mysql_test_commands[] = { { ngx_string("mysql_test"), NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_mysql_test, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_mysql_test_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_mysql_test_create_loc_conf, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_mysql_test_module = { NGX_MODULE_V1, &ngx_http_mysql_test_module_ctx, /* module context */ ngx_http_mysql_test_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_str_t ngx_mysql_login = ngx_string("root"); static ngx_str_t ngx_mysql_passwd = ngx_string("tp"); static ngx_str_t ngx_mysql_database = ngx_string("mysql"); static ngx_str_t ngx_mysql_command_query = ngx_string("select * from user"); static ngx_int_t ngx_http_mysql_test_handler(ngx_http_request_t *r) { ngx_int_t rc; ngx_mysql_t *m; ngx_http_mysql_test_conf_t *mtcf; mtcf = ngx_http_get_module_loc_conf(r, ngx_http_mysql_test_module); m = ngx_pcalloc(r->pool, sizeof(ngx_mysql_t)); if (m == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } m->pool = r->pool; m->handler = ngx_http_mysql_auth; m->data = r; m->login = &ngx_mysql_login; m->passwd = &ngx_mysql_passwd; m->database = &ngx_mysql_database; /* STUB */ m->peer.sockaddr = mtcf->peers[0].sockaddr; m->peer.socklen = mtcf->peers[0].socklen; m->peer.name = &mtcf->peers[0].name; m->peer.tries = mtcf->npeers; m->peer.get = ngx_event_get_peer; /**/ m->peer.log = r->connection->log; m->peer.log_error = NGX_ERROR_ERR; rc = ngx_mysql_connect(m); if (rc == NGX_OK || rc == NGX_AGAIN) { return NGX_DONE; } return NGX_HTTP_INTERNAL_SERVER_ERROR; } static void ngx_http_mysql_auth(ngx_mysql_t *m) { ngx_http_request_t *r; r = m->data; if (m->state != NGX_OK) { ngx_http_finalize_request(r, NGX_HTTP_NO_CONTENT); return; } m->query.len = NGX_MYSQL_CMDPKT_LEN + ngx_mysql_command_query.len; m->query.data = ngx_pnalloc(r->pool, m->query.len); if (m->query.data == NULL) { ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR); return; } ngx_memcpy(m->query.data + NGX_MYSQL_CMDPKT_LEN, ngx_mysql_command_query.data, ngx_mysql_command_query.len); m->handler = ngx_http_mysql_done; ngx_mysql_query(m); } static void ngx_http_mysql_done(ngx_mysql_t *m) { ngx_http_request_t *r; r = m->data; ngx_http_finalize_request(r, NGX_HTTP_NO_CONTENT); } static void * ngx_http_mysql_test_create_loc_conf(ngx_conf_t *cf) { ngx_http_mysql_test_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_mysql_test_conf_t)); if (conf == NULL) { return NGX_CONF_ERROR; } return conf; } static char * ngx_http_mysql_test(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_mysql_test_conf_t *mtcf = conf; ngx_str_t *value; ngx_url_t u; ngx_http_core_loc_conf_t *clcf; clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module); clcf->handler = ngx_http_mysql_test_handler; value = cf->args->elts; ngx_memzero(&u, sizeof(ngx_url_t)); u.url = value[1]; u.default_port = 3306; if (ngx_parse_url(cf->pool, &u) != NGX_OK) { if (u.err) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%s in upstream \"%V\"", u.err, &u.url); } return NGX_CONF_ERROR; } mtcf->peers = u.addrs; mtcf->npeers = u.naddrs; return NGX_CONF_OK; }