Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit874372a

Browse files
committed
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 NaNresult, because the calculation is not well-defined. They used to doso, but since we adopted Youngs-Cramer aggregation in commite954a72,they produced zero instead. That's an oversight, so fix it. Add testsexercising 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/353062.1591898766@sss.pgh.pa.us
1 parent81cd796 commit874372a

File tree

3 files changed

+159
-2
lines changed

3 files changed

+159
-2
lines changed

‎src/backend/utils/adt/float.c‎

Lines changed: 35 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2932,6 +2932,17 @@ float8_accum(PG_FUNCTION_ARGS)
29322932
Sxx=get_float8_nan();
29332933
}
29342934
}
2935+
else
2936+
{
2937+
/*
2938+
* At the first input, we normally can leave Sxx as 0. However, if
2939+
* the first input is Inf or NaN, we'd better force Sxx to NaN;
2940+
* otherwise we will falsely report variance zero when there are no
2941+
* more inputs.
2942+
*/
2943+
if (isnan(newval)||isinf(newval))
2944+
Sxx=get_float8_nan();
2945+
}
29352946

29362947
/*
29372948
* If we're invoked as an aggregate, we can cheat and modify our first
@@ -3006,6 +3017,17 @@ float4_accum(PG_FUNCTION_ARGS)
30063017
Sxx=get_float8_nan();
30073018
}
30083019
}
3020+
else
3021+
{
3022+
/*
3023+
* At the first input, we normally can leave Sxx as 0. However, if
3024+
* the first input is Inf or NaN, we'd better force Sxx to NaN;
3025+
* otherwise we will falsely report variance zero when there are no
3026+
* more inputs.
3027+
*/
3028+
if (isnan(newval)||isinf(newval))
3029+
Sxx=get_float8_nan();
3030+
}
30093031

30103032
/*
30113033
* If we're invoked as an aggregate, we can cheat and modify our first
@@ -3232,6 +3254,19 @@ float8_regr_accum(PG_FUNCTION_ARGS)
32323254
Sxy=get_float8_nan();
32333255
}
32343256
}
3257+
else
3258+
{
3259+
/*
3260+
* At the first input, we normally can leave Sxx et al as 0. However,
3261+
* if the first input is Inf or NaN, we'd better force the dependent
3262+
* sums to NaN; otherwise we will falsely report variance zero when
3263+
* there are no more inputs.
3264+
*/
3265+
if (isnan(newvalX)||isinf(newvalX))
3266+
Sxx=Sxy=get_float8_nan();
3267+
if (isnan(newvalY)||isinf(newvalY))
3268+
Syy=Sxy=get_float8_nan();
3269+
}
32353270

32363271
/*
32373272
* If we're invoked as an aggregate, we can cheat and modify our first

‎src/test/regress/expected/aggregates.out‎

Lines changed: 104 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -127,7 +127,79 @@ SELECT var_samp(b::numeric) FROM aggtest;
127127

128128
-- population variance is defined for a single tuple, sample variance
129129
-- is not
130-
SELECT var_pop(1.0), var_samp(2.0);
130+
SELECT var_pop(1.0::float8), var_samp(2.0::float8);
131+
var_pop | var_samp
132+
---------+----------
133+
0 |
134+
(1 row)
135+
136+
SELECT stddev_pop(3.0::float8), stddev_samp(4.0::float8);
137+
stddev_pop | stddev_samp
138+
------------+-------------
139+
0 |
140+
(1 row)
141+
142+
SELECT var_pop('inf'::float8), var_samp('inf'::float8);
143+
var_pop | var_samp
144+
---------+----------
145+
NaN |
146+
(1 row)
147+
148+
SELECT stddev_pop('inf'::float8), stddev_samp('inf'::float8);
149+
stddev_pop | stddev_samp
150+
------------+-------------
151+
NaN |
152+
(1 row)
153+
154+
SELECT var_pop('nan'::float8), var_samp('nan'::float8);
155+
var_pop | var_samp
156+
---------+----------
157+
NaN |
158+
(1 row)
159+
160+
SELECT stddev_pop('nan'::float8), stddev_samp('nan'::float8);
161+
stddev_pop | stddev_samp
162+
------------+-------------
163+
NaN |
164+
(1 row)
165+
166+
SELECT var_pop(1.0::float4), var_samp(2.0::float4);
167+
var_pop | var_samp
168+
---------+----------
169+
0 |
170+
(1 row)
171+
172+
SELECT stddev_pop(3.0::float4), stddev_samp(4.0::float4);
173+
stddev_pop | stddev_samp
174+
------------+-------------
175+
0 |
176+
(1 row)
177+
178+
SELECT var_pop('inf'::float4), var_samp('inf'::float4);
179+
var_pop | var_samp
180+
---------+----------
181+
NaN |
182+
(1 row)
183+
184+
SELECT stddev_pop('inf'::float4), stddev_samp('inf'::float4);
185+
stddev_pop | stddev_samp
186+
------------+-------------
187+
NaN |
188+
(1 row)
189+
190+
SELECT var_pop('nan'::float4), var_samp('nan'::float4);
191+
var_pop | var_samp
192+
---------+----------
193+
NaN |
194+
(1 row)
195+
196+
SELECT stddev_pop('nan'::float4), stddev_samp('nan'::float4);
197+
stddev_pop | stddev_samp
198+
------------+-------------
199+
NaN |
200+
(1 row)
201+
202+
SELECT var_pop(1.0::numeric), var_samp(2.0::numeric);
131203
var_pop | var_samp
132204
---------+----------
133205
0 |
@@ -139,6 +211,18 @@ SELECT stddev_pop(3.0::numeric), stddev_samp(4.0::numeric);
139211
0 |
140212
(1 row)
141213

214+
SELECT var_pop('nan'::numeric), var_samp('nan'::numeric);
215+
var_pop | var_samp
216+
---------+----------
217+
NaN | NaN
218+
(1 row)
219+
220+
SELECT stddev_pop('nan'::numeric), stddev_samp('nan'::numeric);
221+
stddev_pop | stddev_samp
222+
------------+-------------
223+
NaN | NaN
224+
(1 row)
225+
142226
-- verify correct results for null and NaN inputs
143227
select sum(null::int4) from generate_series(1,3);
144228
sum
@@ -299,6 +383,25 @@ SELECT corr(b, a) FROM aggtest;
299383
0.139634516517873
300384
(1 row)
301385

386+
-- check single-tuple behavior
387+
SELECT covar_pop(1::float8,2::float8), covar_samp(3::float8,4::float8);
388+
covar_pop | covar_samp
389+
-----------+------------
390+
0 |
391+
(1 row)
392+
393+
SELECT covar_pop(1::float8,'inf'::float8), covar_samp(3::float8,'inf'::float8);
394+
covar_pop | covar_samp
395+
-----------+------------
396+
NaN |
397+
(1 row)
398+
399+
SELECT covar_pop(1::float8,'nan'::float8), covar_samp(3::float8,'nan'::float8);
400+
covar_pop | covar_samp
401+
-----------+------------
402+
NaN |
403+
(1 row)
404+
302405
-- test accum and combine functions directly
303406
CREATE TABLE regr_test (x float8, y float8);
304407
INSERT INTO regr_test VALUES (10,150),(20,250),(30,350),(80,540),(100,200);

‎src/test/regress/sql/aggregates.sql‎

Lines changed: 20 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -39,8 +39,22 @@ SELECT var_samp(b::numeric) FROM aggtest;
3939

4040
-- population variance is defined for a single tuple, sample variance
4141
-- is not
42-
SELECT var_pop(1.0), var_samp(2.0);
42+
SELECT var_pop(1.0::float8), var_samp(2.0::float8);
43+
SELECT stddev_pop(3.0::float8), stddev_samp(4.0::float8);
44+
SELECT var_pop('inf'::float8), var_samp('inf'::float8);
45+
SELECT stddev_pop('inf'::float8), stddev_samp('inf'::float8);
46+
SELECT var_pop('nan'::float8), var_samp('nan'::float8);
47+
SELECT stddev_pop('nan'::float8), stddev_samp('nan'::float8);
48+
SELECT var_pop(1.0::float4), var_samp(2.0::float4);
49+
SELECT stddev_pop(3.0::float4), stddev_samp(4.0::float4);
50+
SELECT var_pop('inf'::float4), var_samp('inf'::float4);
51+
SELECT stddev_pop('inf'::float4), stddev_samp('inf'::float4);
52+
SELECT var_pop('nan'::float4), var_samp('nan'::float4);
53+
SELECT stddev_pop('nan'::float4), stddev_samp('nan'::float4);
54+
SELECT var_pop(1.0::numeric), var_samp(2.0::numeric);
4355
SELECT stddev_pop(3.0::numeric), stddev_samp(4.0::numeric);
56+
SELECT var_pop('nan'::numeric), var_samp('nan'::numeric);
57+
SELECT stddev_pop('nan'::numeric), stddev_samp('nan'::numeric);
4458

4559
-- verify correct results for null and NaN inputs
4660
selectsum(null::int4)from generate_series(1,3);
@@ -81,6 +95,11 @@ SELECT regr_slope(b, a), regr_intercept(b, a) FROM aggtest;
8195
SELECT covar_pop(b, a), covar_samp(b, a)FROM aggtest;
8296
SELECT corr(b, a)FROM aggtest;
8397

98+
-- check single-tuple behavior
99+
SELECT covar_pop(1::float8,2::float8), covar_samp(3::float8,4::float8);
100+
SELECT covar_pop(1::float8,'inf'::float8), covar_samp(3::float8,'inf'::float8);
101+
SELECT covar_pop(1::float8,'nan'::float8), covar_samp(3::float8,'nan'::float8);
102+
84103
-- test accum and combine functions directly
85104
CREATETABLEregr_test (x float8, y float8);
86105
INSERT INTO regr_testVALUES (10,150),(20,250),(30,350),(80,540),(100,200);

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp