On 12/6/23 21:56, Nathan Bossart wrote:
On Wed, Dec 06, 2023 at 03:20:46PM -0500, Tom Lane wrote:
If Nathan's perf results hold up elsewhere, it seems like some
micro-optimization around the text-pushing (appendStringInfoString)
might be more useful than caching. The 7% spent in cache lookups
could be worth going after later, but it's not the top of the list.
Hah, it turns out my benchmark of 110M integers really stresses the
JSONTYPE_NUMERIC path in datum_to_json_internal(). That particular path
calls strlen() twice: once for IsValidJsonNumber(), and once in
appendStringInfoString(). If I save the result from IsValidJsonNumber()
and give it to appendBinaryStringInfo() instead, the COPY goes ~8% faster.
It's probably worth giving datum_to_json_internal() a closer look in a new
thread.
Yep, after looking through that code I was going to make the point that
your 11 integer test was over indexing on that one type. I am sure there
are other micro-optimizations to be made here, but I also think that it
is outside the scope of the COPY TO JSON patch.
--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
