Re: [COMMITTERS] pgsql: Efficient transaction-controlled synchronous replication.

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> As a side note, it's not very obvious why some parts of PostmasterMain
> report problems by doing write_stderr() and exit() while other parts
> use ereport(ERROR). This check and the nearby checks on WAL level are
> immediately preceded and followed by other checks that use the
> opposite technique.

This question is answered in postmaster.c's header comment:

* Error Reporting:
* Use write_stderr() only for reporting "interactive" errors
* (essentially, bogus arguments on the command line). Once the
* postmaster is launched, use ereport(). In particular, don't use
* write_stderr() for anything that occurs after pmdaemonize.

Code that is involved in GUC variable processing is in a gray area, though,
since it can be invoked both before and after pmdaemonize. It might be
a good idea to convert all the calls into ereports and maintain a state
flag in elog.c to determine what to do.

regards, tom lane