Horton

Re: Emitting JSON to file using COPY TO

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Joe Conway <mail@joeconway.com>, Daniel Verite <daniel@manitou-mail.org>, Andrew Dunstan <andrew@dunslane.net>, Davin Shearer <davin@apache.org>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Junwang Zhao <zhjwpku@gmail.com>
Date: 2024-02-02T08:25:28Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add option force_array for COPY JSON FORMAT

  2. json format for COPY TO

  3. introduce CopyFormat, refactor CopyFormatOptions

  4. Doc: add IDs to copy.sgml's <varlistentry> and <refsect1>

On Wed, Jan 31, 2024 at 9:26 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> On 2024-Jan-23, jian he wrote:
>
> > > +           | FORMAT_LA copy_generic_opt_arg
> > > +               {
> > > +                   $$ = makeDefElem("format", $2, @1);
> > > +               }
> > >         ;
> > >
> > > I think it's not necessary. "format" option is already handled in
> > > copy_generic_opt_elem.
> >
> > test it, I found out this part is necessary.
> > because a query with WITH like `copy (select 1)  to stdout with
> > (format json, force_array false); ` will fail.
>
> Right, because "FORMAT JSON" is turned into FORMAT_LA JSON by parser.c
> (see base_yylex there).  I'm not really sure but I think it might be
> better to make it "| FORMAT_LA JSON" instead of invoking the whole
> copy_generic_opt_arg syntax.  Not because of performance, but just
> because it's much clearer what's going on.
>

sorry to bother you.
Now I didn't apply any patch, just at the master.
I don't know much about gram.y.

copy (select 1)  to stdout with  (format json1);
ERROR:  COPY format "json1" not recognized
LINE 1: copy (select 1)  to stdout with  (format json1);
                                          ^
copy (select 1) to stdout with  (format json);
ERROR:  syntax error at or near "format"
LINE 1: copy (select 1) to stdout with  (format json);
                                         ^

json is a keyword. Is it possible to escape it?
make `copy (select 1) to stdout with  (format json)` error message the same as
`copy (select 1) to stdout with  (format json1)`