How do I notify a process of an SQLite database change done in a different process?

Question

Let's say I have two or more processes dealing with an SQLite database - a "player" process and many "editor" processes.

The "player" process reads the database and updates a view - in my case it would be a waveform being mixed to the soundcard depending on events stored in the database.

An "editor" process is any editor for that database: it changes the database constantly.

Now I want the player to reflect the editing changes quickly.

I know that SQLite supplies hooks to trace database changes within the same process, but there seems to be little info on how to do this with multiple processes.

I could poll the database constantly, compare records and trigger events, but that seems to be quite inefficient, especially when the database grows to a large size.

I am thinking about using a log table and triggers, but I wonder if there is a simpler method.

Answer 1

If it's on the same machine, the simplest way would be to have named pipe, "player" with blocking read() and "editors" putting a token in pipe whenever they modify DB.