Re: psql - factor out echo code

Hello Tom,

> I went to commit this, figuring that it was a trivial bit of code
> consolidation, but as I looked around in common.c I got rather
> unhappy with the inconsistent behavior of things.  Examining
> the various places that implement "echo"-related logic, we have
> the three places this patch proposes to unify, which log queries
> using
>
>    fprintf(out,
>            _("********* QUERY **********\n"
>              "%s\n"
>              "**************************\n\n"), query);
>
> and then we have two more that just do
>
>    puts(query);
>
> plus this:
>
>    if (!OK && pset.echo == PSQL_ECHO_ERRORS)
>        pg_log_info("STATEMENT:  %s", query);
>
> So it's exactly fifty-fifty as to whether we add all that decoration
> or none at all.  I think if we're going to touch this logic, we
> ought to try to unify the behavior.

+1.

I did not go this way because I wanted it to be a simple restructuring 
patch so that it could go through without much ado, but I agree with 
improving the current status. I'm not sure we want too much ascii-art.

> My vote would be to drop the decoration everywhere, but perhaps there 
> are votes not to?

No, I'd be ok with removing the decoration, or at least simplify them, or 
as you suggest below make the have a useful semantics.

> A different angle is that the identical decoration is used for both
> psql-generated queries that are logged because of ECHO_HIDDEN, and
> user-entered queries.  This seems at best rather unhelpful.

Indeed.

> If we keep the decoration, should we make it different for those two 
> cases?  (Maybe "INTERNAL QUERY" vs "QUERY", for example.)  The cases 
> with no decoration likewise fall into multiple categories, both 
> user-entered and generated-by-gexec; if we were going with a decorated 
> approach I'd think it useful to make a distinction between those, too.
>
> Thoughts?

Yes. Maybe decorations should be SQL comments, and the purpose/origin of 
the query could be made clear as you suggest, eg something like markdown 
in a comment:

   "-- # <whatever> QUERY\n%s\n\n"

with <whatever> in USER DESCRIPTION COMPLETION GEXEC…

-- 
Fabien.