Re: unite recovery.conf and postgresql.conf

> Agreed. This thread has already expended too much of our valuable time,
> in my opinion.

As I said elsewhere, I think that a modified version of Simon's proposal
gets us all what we want except code cleanliness. I'd like to hear from
Tom on that issue.

The proposal is:

1. No changes are expected to PITR mode, unless required by the other
changes below.

2. standby_mode becomes an ENUM: "off,standby,pitr". It can be reset on
server reload or through "pg_ctl promote"

3. we add a "recovery_file" filepath parameter to postgresql.conf. This
points to the location of recovery.conf, if any, but does not error
fatally if the file doesn't exist, allowing recovery.conf/.done if we
want to support it.
3.a. we continue to support recovery.conf/.done trigger file
behavior if recovery_file is set. In this case,
the recovery.conf file would contain the standby_mode GUC.
3.b. should pitr mode require recovery_file? Doesn't seem
like it.
3.c. we begin arguments on whether or not recovery_file
should be set by default

4. Haas implements SET PERSISTENT for postgresql.conf

5. pg_ctl promote uses SET PERSISTENT to change standby_mode so that
former standbys can be permanently promoted.

6. (optional) we add include_if_exists specifier for postgresql.conf,
allowing scripters to handle having a separate recovery.conf file in
other ways.

7. (optional) we add a "pg_ctl standby" command which starts up
postgres and sets standby_mode to "standby". I'm not sure I see the
value in this though.

The above allows DBAs to operate in "backwards compatibility mode"
without forcing authors of new tools and scripts to abide by it.

Question: if both standby_mode and recovery_file are set, what should
happen if the recovery_file is not present? For backwards
compatibility, we would use SET PERSISTENT to set standby_mode after the
server comes up. Arguments?

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com