今日笔记

MYSQL篇

新增如果unique索引字段重复，则更新；

insert into mg_user(key,key2,key3)value(‘value‘,‘value2‘,‘value3‘) on duplicate key update key=value,key2=value2,key3=value3

show global variables；

if(!mysql_real_connect(&logdb, my_hostname, my_user, my_password, my_dbname, my_port, my_sock, 0)){  //mysql长连接
        ast_log(LOG_ERROR, "Failed to connect to mysql database %s on %s.\n", my_dbname, my_hostname); 
        use_mysql = 0; 
} else { 
       char value = 1; 
       mysql_options(&logdb, MYSQL_OPT_RECONNECT, (char*)&value); 
        use_mysql = 1; 
}

NGINX篇

例如，NGINX对一个没有长连接支持的后端机器，会出现大量TIME_WAIT 状态的连接，使用以下命令验证之：
netstat -n | grep TIME_WAIT

1. 启用到 memcache 服务器的长连接
在upstream 配置段中增加 keepalive N 指令即可：

upstream memcached_backend {
    server 127.0.0.1:11211;
    server 10.0.0.2:11211;
     keepalive 32;
}
server {
     ...
     location /memcached/ {
       set $memcached_key $uri;
        memcached_pass memcached_backend;
     }
}

2. 启用fastcgi 长连接支持
除了需要在upstream 中配置 keepalive N 外，还需要在 location 中增加 fastcgi_keep_conn on;
upstream fastcgi_backend {
    server 127.0.0.1:9000;
    keepalive 8;
}

server {
    ...
    location /fastcgi/ {
       fastcgi_pass fastcgi_backend;
       fastcgi_keep_conn on;
        ...
    }
}
3. 启用对后端机器HTTP 长连接支持
upstream http_backend {
    server 127.0.0.1:8080;
    keepalive 16;
}

server {
   location /http/ {
        proxy_pass http://http_backend;
        proxy_http_version 1.1;
       proxy_set_header Connection "";
       ...
   }
}

http://blog.itpub.net/29754888/viewspace-1406479/