PHP REDIS/MYSQL, issue with concurrent connections

I have worked on NodeJs and Redis before. Since NodeJs is a web server I could maintain a single connection to Redis and all the http requests use same Redis client to connect to Redis. But in PHP each page upon HTTP request creates a new connection to Redis Server and this is slowing down the performance. How do they maintain the connection state in PHP? It must be same issue with PHP-Mysql too so I guess there are solutions out the开发者_JS百科re?

The way php works, it that it is a program, not a server. Every time you request a page on your web server, PHP is called to run the program. Once the page is done loading, the thread is ended. PHP is not a server, so once a page is done loading, all connections associated with it are terminated. Therefor, every time a page is requested, a new connection to the database has to be made. If you are noticing a performance issue when connecting, you should try php-redis if you are not already doing so.

Let says you are using php-fpm. php-fpm has a master process and run multiple worker process according the pool configuration.

Each worker process is independent (but can use shared resource such as opcache/APUc cache ...), consume CPU and memory (memory is most important factor to tune the pool configuration max-children property).

So yes, 1 HTTP query = 1 php-fpm worker (fresh or reuse) = 1 new socket connection (or reuse persistent connection), to scale:

• Redis cluster
• Proxy such as HAProxy between php and redis (so you can limit maxconn)
• Use local cache such as APCu to limit Redis access (complicate but the most powerful)
• Check OS ulimit and opened file descriptors