nginx 出现an upstream response is buffered to a temporary file

今天检查机器运行情况的时候在日志里看到这么一条：

2017/02/14 11:25:05 [warn] 32254#32254: *34 an upstream response is buffered to a temporary file /var/cache/nginx/fastcgi_temp/3/00/0000000003 while reading upstream, client: 66.249.73.253, server: www.on0926.com, request: "GET /?p=418 HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "***.**.***"

在网上查了之后，都说是缓存问题，于是在主机的配置文件添加如下字段：

vim /etc/nginx/conf.d/****.conf

location ~ \.php$ {
        root           html;
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_buffer_size 512k;
        fastcgi_buffers 6 512k;
        fastcgi_busy_buffers_size 512k;
        fastcgi_temp_file_write_size 512k;
        fastcgi_index  index.php;
        fastcgi_param  SCRIPT_FILENAME  /******/$fastcgi_script_name;
        include        fastcgi_params;