On Tue, Sep 26, 2017 at 12:29 PM, Andres Freund <and...@anarazel.de> wrote:
> Hi, > > On 2017-09-26 11:59:42 -0700, Jeff Janes wrote: > > Should the release notes have a compatibility entry about pg_ctl restart, > > being used against a running pre-10 server, no longer being able to > detect > > when startup is complete? > > > > I don't know if cross-version use of pg_ctl restart was ever officially > > supported, but the current behavior is rather confusing (waiting for a > long > > time, and then reporting failure, even though it started successfully). > > I'm actually tempted to just make pg_ctl verify the right version of > postgres is being used. Maybe I'm missing something, but what's the > use-case for allowing it, and every couple releases have some breakage? > The use case for me is that I have multiple versions of postgres running on the same machine, and don't want check which pg_ctl is in my path each time I change one of their configurations and need to restart it. Or at least, I never had to check before, as pg_ctl goes out of its way to restart it with the same bin/postgres that the server is currently running with, rather than restarting with the bin/postgres currently in the path, or whichever bin/postgres is in the same directory as the bin/pg_ctl. (Which is itself not an unmitigated win, but it is what I'm used to). Admittedly, this is a much bigger problem with hacking/testing than it is with production use, but still I do have production machines with mixed versions running, and can see myself screwing this up a few times once one of them gets upgraded to v10, even with an incompatibility warning in the release notes. But at least I had fair warning. To add insult to injury, when v10 pg_ctl does restart a pre-10 server and it sits there for a long time waiting for it to start up even though it has already started up, if I hit ctrl-C because I assume something is horribly wrong, it then goes ahead and kills the successfully started-and-running server. If we do want to do a version check and fail out, I think it should check before shutting it down, rather than shutting it down and then refusing to start. Cheers, Jeff
