Horton

Re: Emitting JSON to file using COPY TO

Joe Conway <mail@joeconway.com>

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From: Joe Conway <mail@joeconway.com>
To: Daniel Verite <daniel@manitou-mail.org>
Cc: Andrew Dunstan <andrew@dunslane.net>, Davin Shearer <davin@apache.org>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-12-08T21:26:40Z
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 12/8/23 14:45, Daniel Verite wrote:
> 	Joe Conway wrote:
> 
>> copyto_json.007.diff
> 
> When the source has json fields with non-significant line feeds, the COPY
> output has these line feeds too, which makes the output incompatible
> with rule #2 at https://jsonlines.org  ("2. Each Line is a Valid JSON
> Value").
> 
> create table j(f json);
> 
> insert into j values('{"a":1,
> "b":2
> }');
> 
> copy j to stdout (format json);
> 
> Result:
> {"f":{"a":1,
> "b":2
> }}
> 
> Is that expected? copy.sgml in 007 doesn't describe the output
> in terms of lines so it's hard to tell from the doc.

The patch as-is just does the equivalent of row_to_json():
8<----------------------------
select row_to_json(j) from j;
  row_to_json
--------------
  {"f":{"a":1,+
  "b":2       +
  }}
(1 row)
8<----------------------------

So yeah, that is how it works today. I will take a look at what it would 
take to fix it.


-- 
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com