From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael Paquier <michael@paquier.xyz>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Inconsistent error message wording for REINDEX CONCURRENTLY
In-reply-to: <20190504085543.GE2174@paquier.xyz>
References: <23694.1556806002@sss.pgh.pa.us>
 <20190504085543.GE2174@paquier.xyz>
Comments: In-reply-to Michael Paquier <michael@paquier.xyz>
	message dated "Sat, 04 May 2019 17:55:43 +0900"
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Date: Sat, 04 May 2019 11:00:11 -0400
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Michael Paquier <michael@paquier.xyz> writes:
> On Thu, May 02, 2019 at 10:06:42AM -0400, Tom Lane wrote:
>> regression=3D# reindex index concurrently pg_class_oid_index;
>> psql: ERROR:  concurrent reindex is not supported for catalog relations
>> regression=3D# reindex table concurrently pg_class; =

>> psql: ERROR:  concurrent index creation on system catalog tables is not=
 supported
>> =

>> It'd be nice though if those error messages gave the impression of havi=
ng
>> been written on the same planet.

> We could do a larger brush-up of error messages in this area, as these
> are full sentences which is not a style allowed, no?

I wouldn't object to either one in isolation, it's the inconsistency
that irks me.

> How about the following changes
> for at least these two?
> "cannot use REINDEX CONCURRENTLY on system catalogs"
> "cannot create index on system catalog concurrently"

I'd suggest something like "cannot reindex a system catalog concurrently"
for both cases.  The "cannot create index" wording doesn't seem to me to
be very relevant, because if you try that you'll get

regression=3D# create index on pg_class(relchecks);
psql: ERROR:  permission denied: "pg_class" is a system catalog

> Then we have some other messages in index.c which could be cleaned
> up..  For example at the beginning of index_constraint_create(), there
> are two them, but there is much more which could be improved.  Do you
> think this is worth having a look and fixing?

I'm not excited about rewording longstanding errors.  These two are
new though (aren't they?)

			regards, tom lane