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

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> Joachim Wieland <joe(at)mcknight(dot)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