Horton

Re: Emitting JSON to file using COPY TO

Joe Conway <mail@joeconway.com>

View thread
From: Joe Conway <mail@joeconway.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andrew Dunstan <andrew@dunslane.net>, Davin Shearer <davin@apache.org>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-12-06T16:19:19Z
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 12/6/23 10:44, Tom Lane wrote:
> Joe Conway <mail@joeconway.com> writes:
>> I believe this is ready to commit unless there are further comments or 
>> objections.
> 
> I thought we were still mostly at proof-of-concept stage?

The concept is narrowly scoped enough that I think we are homing in on 
the final patch.

> In particular, has anyone done any performance testing?
> I'm concerned about that because composite_to_json() has
> zero capability to cache any metadata across calls, meaning
> there is going to be a large amount of duplicated work
> per row.

I will devise some kind of test and report back. I suppose something 
with many rows and many narrow columns comparing time to COPY 
text/csv/json modes would do the trick?

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