Re: How about a psql backslash command to show GUCs? - Mailing list pgsql-hackers

From David G. Johnston
Subject Re: How about a psql backslash command to show GUCs?
Date
Msg-id CAKFQuwab7BqXMKnqd=QBJF_XLnBiKSrGfA2xUeP9Yja2cCeH3g@mail.gmail.com
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In response to Re: How about a psql backslash command to show GUCs?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Sat, Apr 9, 2022 at 9:27 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
"Jonathan S. Katz" <jkatz@postgresql.org> writes:
> -1, at least for the moment. Sometimes a user doesn't know what they're
> looking for coupled with being unaware of what the default value is. If
> a setting is set to a default value and that value is the problematic
> setting, a user should be able to see that even in a full list.

Sure, but then you do "\dconfig *".  With there being several hundred
GUCs (and no doubt more coming), I'm not sure that "show me every GUC"
is a common use-case at all, let alone so common as to deserve being
the default behavior.


I'm for having a default that doesn't mean "show everything".

I'm also wondering whether we can invent GUC namespaces for the different contexts, so I can use a pattern like: context.internal.*

A similar ability for category would be nice but we'd have to invent labels to make it practical.

\dconfig [pattern [mode]]

mode: all, overridden

So mode is overridden if pattern is absent but all if pattern is present, with the ability to specify overridden.

pattern: [[{context.{context label}}|{category.{category label}}.]...]{parameter name pattern}
parameter name pattern: [{two part name prefix}.]{base parameter pattern}


One thing we could perhaps do to reduce confusion is to change the
table heading when doing this, say from "List of configuration parameters"
to "List of non-default configuration parameters".


I'd be inclined to echo a note after the output table that says that not all configuration parameters are displayed - possibly even providing a count [all - overridden].  The header is likely to be ignored even if it still ends up on screen after scrolling.

David J.

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