It seems works fine when the output size is small. but it will occur in some probability when the output size (about 14000 k) is big, The probability of occurrence is about 40% ~ 50%.

Below is relative info.

error_log sample
```
[alert] 6#6: *130 header already sent while sending response to client, client: xxx, server: xxx, request: "GET /my-page HTTP/1.1", subrequest: "xxxhtml", host: "xxx"
```

access log sample

```
[06/Nov/2018:02:06:15 +0000] "GET /my-page HTTP/1.1" 200 0 "-" "Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1"
```

nginx info

```
nginx -V
nginx version: nginx/1.15.5
built by gcc 6.3.0 20170516 (Debian 6.3.0-18+deb9u1)
built with OpenSSL 1.1.0f 25 May 2017
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-g -O2 -fdebug-prefix-map=/data/builder/debuild/nginx-1.15.5/debian/debuild-base/nginx-1.15.5=. -specs=/usr/share/dpkg/no-pie-compile.specs -fstack-protector-strong -Wformat -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fPIC' --with-ld-opt='-specs=/usr/share/dpkg/no-pie-link.specs -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -pie'
```

My nginx config:

1. nginx.conf
```
user nginx;
worker_processes 1;

error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;


events {
worker_connections 1024;
}


http {
include /etc/nginx/mime.types;
default_type application/octet-stream;

log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';

access_log /var/log/nginx/access.log main;

sendfile on;
#tcp_nopush on;

keepalive_timeout 65;

#gzip on;

include /etc/nginx/conf.d/*.conf;
}
```

2. server.conf
```
server {
listen 80;
server_name xxx;
root xxx;

disable_symlinks off;
gzip on;
gzip_disable "msie6";

gzip_vary on;
gzip_proxied any;
gzip_comp_level 6;
gzip_buffers 16 8k;
gzip_http_version 1.1;
gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

add_header X-XSS-Protection "1; mode=block";
add_header X-Content-Type-Options "nosniff";
#add_header Cache-Control "max-age=0, private, no-store, no-cache, must-revalidate";

location / {
try_files $uri /index.php$is_args$args;
index index.php;
}

location ~ [^/]\.php(/|$) {
ssi on;
fastcgi_split_path_info ^(.+?\.php)(/.*)$;
#if (!-f $document_root$fastcgi_script_name) {
# return 404;
#}
fastcgi_read_timeout 120s;
fastcgi_send_timeout 120s;
fastcgi_pass php-fpm:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME /usr/local/rms/evt/toto/public$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
fastcgi_param PATH_TRANSLATED /usr/local/rms/evt/toto/public$fastcgi_path_info;
}

rewrite_log on;
error_log /var/log/nginx/project_error.log debug;
access_log /var/log/nginx/project_access.log;
error_page 500 503 /error50x.html;
error_page 404 /error404.html;
}
```

3. fastcgi_params

```
fastcgi_param QUERY_STRING $query_string;
fastcgi_param REQUEST_METHOD $request_method;
fastcgi_param CONTENT_TYPE $content_type;
fastcgi_param CONTENT_LENGTH $content_length;

fastcgi_param SCRIPT_NAME $fastcgi_script_name;
fastcgi_param REQUEST_URI $request_uri;
fastcgi_param DOCUMENT_URI $document_uri;
fastcgi_param DOCUMENT_ROOT $document_root;
fastcgi_param SERVER_PROTOCOL $server_protocol;
fastcgi_param REQUEST_SCHEME $scheme;
fastcgi_param HTTPS $https if_not_empty;

fastcgi_param GATEWAY_INTERFACE CGI/1.1;
fastcgi_param SERVER_SOFTWARE nginx/$nginx_version;

fastcgi_param REMOTE_ADDR $remote_addr;
fastcgi_param REMOTE_PORT $remote_port;
fastcgi_param SERVER_ADDR $server_addr;
fastcgi_param SERVER_PORT $server_port;
fastcgi_param SERVER_NAME $server_name;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param REDIRECT_STATUS 200;
```



Edited 1 time(s). Last edit at 11/05/2018 09:51PM by junlin.chen.

I solved the problem by disabling "fastcgi_buffering" or increasing fastcgi_buffer_size. Before nginx uses default buffer size and it failed.

It seems irrelevant to ssi but ssi somehow trigger the error. But still I don't know why there was multiple empty response. Can anybody have any explanation about this?