Subject: Description of SIGHUP GUC parameters

From: Tom Lane <[email-masked]>
Date: Sat, 21 Jan 2006 14:46:03 -0500

Currently, the standard boilerplate description of a SIGHUP parameter
is

        This option can only be set at server start or in the
        <filename>postgresql.conf</filename> file.

We've heard from more than one person who found this confusing ---
frequently it's misread as saying that the parameter cannot be changed
after postmaster start.  Doubtless this is partly because the
boilerplate phrase for a POSTMASTER parameter is

        This option can only be set at server start.

However, previous discussions have dried up without coming up with a
better phrase.  It occurred to me today that this might work better:

        This option can only be set in the <filename>postgresql.conf</>
        file or on the server command line.

I think mentioning the config file first is important to focus attention
on that.  The only other way to set these parameters is via command-line
switches, so we should just say that rather than emphasizing the "server
start time" aspect of it, which is exactly what not to emphasize.

Comments?

			regards, tom lane

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From: Simon Riggs <[email-masked]>
Date: Wed, 08 Feb 2006 22:17:56 +0000

> start time" aspect of it, which is exactly what not to emphasize.

Just seen this again today and agree its confusing. 

<wildassertion>I think most people think that all parameters can only be
set at server start, until they have dug deeper. Most other systems
software requires a restart to pick up new parameters</wildassertion>

Why not simply use the technical phrase: "SIGHUP" etc. We can just say
'these terms are shorthand for "......" '

I'm not crazy about the terms but at least it is explicit and accurate.
It would also allow us to have a much longer description of all of the
implications and difficulties of each mode.

Best Regards, Simon Riggs

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From: Tom Lane <[email-masked]>
Date: Wed, 08 Feb 2006 18:49:35 -0500

> implications and difficulties of each mode.

We have all that in the introductory section; the references made in the
per-variable descriptions really have no impact on how verbose the
introductory text is ...

			regards, tom lane