Re: Allow reload recovery.conf during recovery

On Fri, May 04, 2018 at 05:19:26PM +0300, Sergei Kornilov wrote:
> I did not find previous discussions.

There have been a lot of discussions across the years about switching
recovery parameters to use the GUC infrastructure, please see those
two ones:
https://www.postgresql.org/message-id/CABUevEy5aWuwySXEC6i3JA6cvy8agGZHQbOn0RVZ4h4oxM0Dkw%40mail.gmail.com
https://www.postgresql.org/message-id/CAJKUy5id1eyweK0W4%2ByyCM6%2B-qYs9erLidUmb%3D1a-QYBgTW4Qw%40mail.gmail.com

And more recently this one which reached a kind of agreement:
https://www.postgresql.org/message-id/CANP8%2BjLO5fmfudbB1b1iw3pTdOK1HBM%3DxMTaRfOa5zpDVcqzew%40mail.gmail.com

Parameters in recovery.conf now have a level equivalent to
GUC_POSTMASTER as those are just read when the startup process finds a
recovery.conf file and are never changed.  Before making some of them as
reloadable, let's switch them to be GUCs first and not re-invent the
SIGHUP handling of parameters as your patch does.  And after let's
discuss about switching some of them to GUC_SIGHUP.
--
Michael