From ccfe3dbaa4392ec1cf50224c57eccd0f34ce8d1d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 21 Jun 2025 12:52:37 -0400 Subject: [PATCH] Doc: improve documentation about width_bucket(). Specify whether the bucket bounds are inclusive or exclusive, and improve some other vague language. Explain the behavior that occurs when the "low" bound is greater than the "high" bound. Make width_bucket_numeric's comment more like that for width_bucket_float8, in particular noting that infinite bounds are rejected (since they became possible in v14). Reported-by: Ben Peachey Higdon Author: Robert Treat Co-authored-by: Tom Lane Reviewed-by: Dean Rasheed Discussion: https://postgr.es/m/2BD74F86-5B89-4AC1-8F13-23CED3546AC1@gmail.com Backpatch-through: 13 --- doc/src/sgml/func.sgml | 18 ++++++++++++++---- src/backend/utils/adt/float.c | 4 ++-- src/backend/utils/adt/numeric.c | 7 ++++--- 3 files changed, 20 insertions(+), 9 deletions(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 5c7e0f9c02d..7a6ca392484 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -1739,13 +1739,23 @@ repeat('Pg', 4) PgPgPgPg which operand falls in a histogram having count equal-width buckets spanning the range low to high. - Returns 0 + The buckets have inclusive lower bounds and exclusive upper bounds. + Returns 0 for an input less + than low, or count+1 for an input - outside that range. + greater than or equal to high. + If low > high, + the behavior is mirror-reversed, with bucket 1 + now being the one just below low, and the + inclusive bounds now being on the upper side. width_bucket(5.35, 0.024, 10.06, 5) 3 + + + width_bucket(9, 10, 0, 10) + 2 @@ -1757,8 +1767,8 @@ repeat('Pg', 4) PgPgPgPg Returns the number of the bucket in which operand falls given an array listing the - lower bounds of the buckets. Returns 0 for an - input less than the first lower + inclusive lower bounds of the buckets. + Returns 0 for an input less than the first lower bound. operand and the array elements can be of any type having standard comparison operators. The thresholds array must be diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c index 63bb0f22772..9b7e0af4bad 100644 --- a/src/backend/utils/adt/float.c +++ b/src/backend/utils/adt/float.c @@ -4004,8 +4004,8 @@ float84ge(PG_FUNCTION_ARGS) * in the histogram. width_bucket() returns an integer indicating the * bucket number that 'operand' belongs to in an equiwidth histogram * with the specified characteristics. An operand smaller than the - * lower bound is assigned to bucket 0. An operand greater than the - * upper bound is assigned to an additional bucket (with number + * lower bound is assigned to bucket 0. An operand greater than or equal + * to the upper bound is assigned to an additional bucket (with number * count+1). We don't allow "NaN" for any of the float8 inputs, and we * don't allow either of the histogram bounds to be +/- infinity. */ diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index e5f2551bf04..f6aeaff7c0e 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -1764,9 +1764,10 @@ generate_series_step_numeric(PG_FUNCTION_ARGS) * in the histogram. width_bucket() returns an integer indicating the * bucket number that 'operand' belongs to in an equiwidth histogram * with the specified characteristics. An operand smaller than the - * lower bound is assigned to bucket 0. An operand greater than the - * upper bound is assigned to an additional bucket (with number - * count+1). We don't allow "NaN" for any of the numeric arguments. + * lower bound is assigned to bucket 0. An operand greater than or equal + * to the upper bound is assigned to an additional bucket (with number + * count+1). We don't allow "NaN" for any of the numeric inputs, and we + * don't allow either of the histogram bounds to be +/- infinity. */ Datum width_bucket_numeric(PG_FUNCTION_ARGS)