Re: Emitting JSON to file using COPY TO - Mailing list pgsql-hackers

On Wed, Dec 06, 2023 at 11:28:59AM -0500, Tom Lane wrote:
> It might be acceptable to plan on improving the performance later,
> depending on just how bad it is now.

On 10M rows with 11 integers each, I'm seeing the following:

    (format text)
    Time: 10056.311 ms (00:10.056)
    Time: 8789.331 ms (00:08.789)
    Time: 8755.070 ms (00:08.755)

    (format csv)
    Time: 12295.480 ms (00:12.295)
    Time: 12311.059 ms (00:12.311)
    Time: 12305.469 ms (00:12.305)

    (format json)
    Time: 24568.621 ms (00:24.569)
    Time: 23756.234 ms (00:23.756)
    Time: 24265.730 ms (00:24.266)

'perf top' tends to look a bit like this:

  13.31%  postgres                      [.] appendStringInfoString
   7.57%  postgres                      [.] datum_to_json_internal
   6.82%  postgres                      [.] SearchCatCache1
   5.35%  [kernel]                      [k] intel_gpio_irq
   3.57%  postgres                      [.] composite_to_json
   3.31%  postgres                      [.] IsValidJsonNumber

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com