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From: Joe Conway <mail@joeconway.com>
To: Andrew Dunstan <andrew@dunslane.net>
To: Davin Shearer <davin@apache.org>
To: PostgreSQL-development <pgsql-hackers@postgreSQL.org>
Subject: Re: Emitting JSON to file using COPY TO
Date: Sun, 3 Dec 2023 15:09:36 -0500
Message-ID: <cb63a985-35a5-4f1e-a551-32166e18112c@joeconway.com> (raw)
In-Reply-To: <6603ea04-8ec3-67b2-e9f6-e00fd0e46858@dunslane.net>
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	<24e3ee88-ec1e-421b-89ae-8a47ee0d2df1@joeconway.com>
	<b22367ef-6ac1-e1c0-da05-0e760e1b7e29@dunslane.net>
	<8c88da85-c197-4765-96f8-a9a1c78305a6@joeconway.com>
	<a70d33fb-76f8-40a8-9a5f-7e03b120e661@joeconway.com>
	<6603ea04-8ec3-67b2-e9f6-e00fd0e46858@dunslane.net>

On 12/3/23 14:52, Andrew Dunstan wrote:
> 
> On 2023-12-03 Su 14:24, Joe Conway wrote:
>> On 12/3/23 11:03, Joe Conway wrote:
>>> On 12/3/23 10:10, Andrew Dunstan wrote:
>>>> I  realize this is just a POC, but I'd prefer to see 
>>>> composite_to_json()
>>>> not exposed. You could use the already public datum_to_json() instead,
>>>> passing JSONTYPE_COMPOSITE and F_RECORD_OUT as the second and third
>>>> arguments.
>>>
>>> Ok, thanks, will do
>>
>> Just FYI, this change does loose some performance in my not massively 
>> scientific A/B/A test:
>>
>> 8<---------------------------
<snip>
>> 8<---------------------------
>>
>> That is somewhere in the 3% range.
> 
> I assume it's because datum_to_json() constructs a text value from which
> you then need to extract the cstring, whereas composite_to_json(), just
> gives you back the stringinfo. I guess that's a good enough reason to go
> with exposing composite_to_json().

Yeah, that was why I went that route in the first place. If you are good 
with it I will go back to that. The code is a bit simpler too.

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






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