3.0.2: rlm_sql_null duplicating its statements

[Alan DeKok]

Arran Cudbard-Bell wrote:
> See this is why I wasn't quite sure why you did this on a per module basis.

  It's simple, it works, and it's a step ahead.

  Only weird people (cough STEFAN) have multiple modules logging to the
same file.

> My suggestion would be to use a global hash of filenames -> FDs, which is
> shared between all things that write to log files on the server.

  The existing code works.  It's easy to make a global log context, just
make a global variable, and have the modules use it.

> My other suggestion to use multiple FDs would also work alleviate some of
> the contention.

  I don't see how that helps... you still have contention when multiple
modules are writing to the same file.  You've just moved it from one
place to another.

> You can just use one mutex, but two would probably be better. You really
> want to limit the critical region for the one global mutex, and locking
> another mutex is probably quicker than doing a bunch of system calls.

  Yes.  The log file code tries hard to minimize contention.

  Alan DeKok.