Question

I have a RESTful web service with a C++ API at the back-end. I am using the FastCGI library to facilitate the REST interface. My C++ API has multiple functions that may be used independently. I am looking for a way to make it as fast as possible. Here are a few ideas I got:

1. Have one FastCGI application that gets the function to be executed, executes that function and returns the output. This way the API calls keep waiting until one ‘function’ is complete, even though the next call is for a different independent function.

2. Have multiple FastCGI applications, each having access to only one function from the API, each getting inputs for that particular app and returning outputs of that particular app alone.

This way I can have concurrent calls made to all the different functions, and separate process queues would be made for each function that I have, instead of having one generic process queue to the FastCGI application consisting of calls to different independent functions.

While this looks like it would perform better, I am not sure if it is possible to implement a system such as this – i.e having many FastCGI apps running in parallel from the same server. If it is possible, can someone tell me how to implement this?

Answer 1

Each FastCGI application is a separate program, running in a loop, and communicating with Apache in a binary protocol defined by FastCGI specification. The only possible concurrency problems are the same concurrency problems you would experience if you were running concurrent CGI or PHP requests, with just one exception: since FastCGI processes do not terminate, any limited resources will have to be carefully managed. For example, if you only have a ten-client licence to a database server, you can’t have eleven FastCGI processes using the database unless you manage connections better than “open at start, let it close at the end” method often used in CGI or PHP.