I like the idea of a command as well, for flexibility. If you want a
signal, you can write a trivial command that sends the signal... Maximum flexibility, as long as we don't create a lot of caveats for users.
Agreed, I think it is also easier to understand the mechanism (instead of a signal), and would allow for some reuse of already existing scripts.
If we do use a full command (vs a signal), I propose we do also offer the %p and %f placeholders for the command.
Agreed. It shouldn't be that hard and could be very useful. If nothing else it will eliminate the need to configure path to the pg_receivexlog queue in the archiver.
Is there actual value in providing both %p and %f? It's not like it's really hard to do, but since the path will be specified on the same commandline, you could just put it in the command?