I have a shared hosting server with high traffic.

I have a lightweight apache mod_proxy for static content that from time to time has a "504 proxy error" problem proxing to apache/mod_php. Error log says:

error reading status line from remote server 127.0.0.1:8080
Error reading from remote server returned by /

This is what the apache documentation says about it.

proxy-initial-not-pooled

If this variable is set no pooled connection will be reused if the client connection is an initial connection. This avoids the "proxy: error reading status line from remote server" error message caused by the race condition that the backend server closed the pooled connection after the connection check by the proxy and before data sent by the proxy reached the backend. It has to be kept in mind that setting this variable downgrades performance, especially with HTTP/1.0 clients.

I am really concerned about this downgrade in performance therefore I started to look at nginx immediately.

I am new to nginx and time is crucial right now, I can't afford to waste days to study it just to find out there is the same race condition issue.

Is nginx affected by this connection pool race condition?

Thanks