Re: Allow commenting of variables in postgresql.conf to - try 4

* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> Joachim Wieland <joe@mcknight.de> writes:
> > I did not check the changes you have done to set_config_option and the like
> > but tested the commenting / uncommenting / changing of guc variables and the
> > behavior and log output. The general idea (at least my idea) is that
> > whenever a SIGHUP is received and there is some difference between the
> > config file and the active value that the server is using, a notice message
> > is written to the log.
>
> Notice message?  Where did that come from?  The behavior I thought
> people were after was just that variables previously defined by the file
> would revert to reset values if not any longer defined by the file.

There's two issues here, I believe.  There's the
'revert-to-reset-values' issue for things which can be changed with a
reload and then there's also the 'notice-message-if-unable-to-change'
a given variable without a reset.

On reload a variable is changed:

#1: That variable can be changed by a reload.
    If the variable has been removed/commented-out then it is reverted
    to the reset-value.  Otherwise, the new value is used.

#2: That variable can *not* be changed by a reload.
    Notice-level message is sent to the log notifying the admin that the
    change requested could not be performed.  This change could be
    either a revert to reset-value if it was removed/commented-out or an
    explicit change request to a different value.

Personally, I'm very interested in having both.  I'm about 90% sure both
were discussed previously on hackers and that the general consensus was
that both were good.  It's possible the second point wasn't noticed by
everyone involved though.  Of course, I might be misunderstanding what
Joachim was referring to also.

    Thanks,

        Stephen