Fix behavior of float aggregates for single Inf or NaN inputs. When there is just one non-null input value, and it is infinity or NaN, aggregates such as stddev_pop and covar_pop should produce a NaN result, because the calculation is not well-defined. They used to do so, but since we adopted Youngs-Cramer aggregation in commit e954a727f, they produced zero instead. That's an oversight, so fix it. Add tests exercising these edge cases.
Affected aggregates are var_pop(double precision) stddev_pop(double precision) var_pop(real) stddev_pop(real) regr_sxx(double precision,double precision) regr_syy(double precision,double precision) regr_sxy(double precision,double precision) regr_r2(double precision,double precision) regr_slope(double precision,double precision) regr_intercept(double precision,double precision) covar_pop(double precision,double precision) corr(double precision,double precision) Back-patch to v12 where the behavior change was accidentally introduced. Report and patch by me; thanks to Dean Rasheed for review. Discussion: https://postgr.es/m/[email protected] Branch ------ REL_12_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/874372a941a6ee31ba4034db0367e0929e5f49bc Modified Files -------------- src/backend/utils/adt/float.c | 35 +++++++++++ src/test/regress/expected/aggregates.out | 105 ++++++++++++++++++++++++++++++- src/test/regress/sql/aggregates.sql | 21 ++++++- 3 files changed, 159 insertions(+), 2 deletions(-)
