Micro-optimize datatype conversions in datum_to_jsonb_internal. The general case for converting to a JSONB numeric value is to run the source datatype's output function and then numeric_in, but we can do substantially better than that for integer and numeric source values. This patch improves the speed of jsonb_agg by 30% for integer input, and nearly 2X for numeric input.
Sadly, the obvious idea of using float4_numeric and float8_numeric to speed up those cases doesn't work: they are actually slower than the generic coerce-via-I/O method, and not by a small amount. They might round off differently than this code has historically done, too. Leave that alone pending possible changes in those functions. We can also do better than the existing code for text/varchar/bpchar source data; this optimization is similar to one that already exists in the json_agg() code. That saves 20% or so for such inputs. Also make a couple of other minor improvements, such as not giving JSONTYPE_CAST its own special case outside the switch when it could perfectly well be handled inside, and not using dubious string hacking to detect infinity and NaN results. Author: Tom Lane <[email protected]> Reviewed-by: jian he <[email protected]> Reviewed-by: Chao Li <[email protected]> Discussion: https://postgr.es/m/[email protected] Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/005a2907dc304eadb00719e5b6e08cd2cf329829 Modified Files -------------- src/backend/utils/adt/jsonb.c | 115 +++++++++++++++++++++++++++++------------- 1 file changed, 81 insertions(+), 34 deletions(-)
