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Fix avg_over_time for nan and float64 overflows (#7346)

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* Fix avg_over_time with Inf and NaN values

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
This commit is contained in:
Julien Pivotto 2020-07-13 17:30:50 +02:00 committed by GitHub
parent 65d805a642
commit d77b56e88e
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 211 additions and 2 deletions
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20
promql/engine.go
View file

@ -2005,7 +2005,25 @@ func (ev *evaluator) aggregation(op parser.ItemType, grouping []string, without
case parser.AVG:
group.groupCount++
group.mean += (s.V - group.mean) / float64(group.groupCount)
if math.IsInf(group.mean, 0) {
if math.IsInf(s.V, 0) && (group.mean > 0) == (s.V > 0) {
// The `mean` and `s.V` values are `Inf` of the same sign. They
// can't be subtracted, but the value of `mean` is correct
// already.
break
}
if !math.IsInf(s.V, 0) && !math.IsNaN(s.V) {
// At this stage, the mean is an infinite. If the added
// value is neither an Inf or a Nan, we can keep that mean
// value.
// This is required because our calculation below removes
// the mean value, which would look like Inf += x - Inf and
// end up as a NaN.
break
}
}
// Divide each side of the `-` by `group.groupCount` to avoid float64 overflows.
group.mean += s.V/float64(group.groupCount) - group.mean/float64(group.groupCount)
case parser.GROUP:
// Do nothing. Required to avoid the panic in `default:` below.

19
promql/functions.go
View file

@ -354,7 +354,24 @@ func funcAvgOverTime(vals []parser.Value, args parser.Expressions, enh *EvalNode
var mean, count float64
for _, v := range values {
count++
mean += (v.V - mean) / count
if math.IsInf(mean, 0) {
if math.IsInf(v.V, 0) && (mean > 0) == (v.V > 0) {
// The `mean` and `v.V` values are `Inf` of the same sign. They
// can't be subtracted, but the value of `mean` is correct
// already.
continue
}
if !math.IsInf(v.V, 0) && !math.IsNaN(v.V) {
// At this stage, the mean is an infinite. If the added
// value is neither an Inf or a Nan, we can keep that mean
// value.
// This is required because our calculation below removes
// the mean value, which would look like Inf += x - Inf and
// end up as a NaN.
continue
}
}
mean += v.V/count - mean/count
}
return mean
})

77
promql/testdata/aggregators.test vendored
View file

@ -320,3 +320,80 @@ eval instant at 1m group without(point)(data)
eval instant at 1m group(foo)
{} 1
# Tests for avg.
clear
load 10s
data{test="ten",point="a"} 8
data{test="ten",point="b"} 10
data{test="ten",point="c"} 12
data{test="inf",point="a"} 0
data{test="inf",point="b"} Inf
data{test="inf",point="d"} Inf
data{test="inf",point="c"} 0
data{test="-inf",point="a"} -Inf
data{test="-inf",point="b"} -Inf
data{test="-inf",point="c"} 0
data{test="inf2",point="a"} Inf
data{test="inf2",point="b"} 0
data{test="inf2",point="c"} Inf
data{test="-inf2",point="a"} -Inf
data{test="-inf2",point="b"} 0
data{test="-inf2",point="c"} -Inf
data{test="inf3",point="b"} Inf
data{test="inf3",point="d"} Inf
data{test="inf3",point="c"} Inf
data{test="inf3",point="d"} -Inf
data{test="-inf3",point="b"} -Inf
data{test="-inf3",point="d"} -Inf
data{test="-inf3",point="c"} -Inf
data{test="-inf3",point="c"} Inf
data{test="nan",point="a"} -Inf
data{test="nan",point="b"} 0
data{test="nan",point="c"} Inf
data{test="big",point="a"} 9.988465674311579e+307
data{test="big",point="b"} 9.988465674311579e+307
data{test="big",point="c"} 9.988465674311579e+307
data{test="big",point="d"} 9.988465674311579e+307
data{test="-big",point="a"} -9.988465674311579e+307
data{test="-big",point="b"} -9.988465674311579e+307
data{test="-big",point="c"} -9.988465674311579e+307
data{test="-big",point="d"} -9.988465674311579e+307
data{test="bigzero",point="a"} -9.988465674311579e+307
data{test="bigzero",point="b"} -9.988465674311579e+307
data{test="bigzero",point="c"} 9.988465674311579e+307
data{test="bigzero",point="d"} 9.988465674311579e+307
eval instant at 1m avg(data{test="ten"})
{} 10
eval instant at 1m avg(data{test="inf"})
{} Inf
eval instant at 1m avg(data{test="inf2"})
{} Inf
eval instant at 1m avg(data{test="inf3"})
{} NaN
eval instant at 1m avg(data{test="-inf"})
{} -Inf
eval instant at 1m avg(data{test="-inf2"})
{} -Inf
eval instant at 1m avg(data{test="-inf3"})
{} NaN
eval instant at 1m avg(data{test="nan"})
{} NaN
eval instant at 1m avg(data{test="big"})
{} 9.988465674311579e+307
eval instant at 1m avg(data{test="-big"})
{} -9.988465674311579e+307
eval instant at 1m avg(data{test="bigzero"})
{} 0

97
promql/testdata/functions.test vendored
View file

@ -395,10 +395,107 @@ eval instant at 8000s holt_winters(http_requests[1m], 0.01, 0.1)
clear
load 10s
metric 1 2 3 4 5
metric2 1 2 3 4 Inf
metric3 1 2 3 4 -Inf
metric4 1 2 3 Inf -Inf
metric5 Inf 0 Inf
metric5b Inf 0 Inf
metric5c Inf Inf Inf -Inf
metric6 1 2 3 -Inf -Inf
metric6b -Inf 0 -Inf
metric6c -Inf -Inf -Inf Inf
metric7 1 2 -Inf -Inf Inf
metric8 9.988465674311579e+307 9.988465674311579e+307
metric9 -9.988465674311579e+307 -9.988465674311579e+307 -9.988465674311579e+307
metric10 -9.988465674311579e+307 9.988465674311579e+307
eval instant at 1m avg_over_time(metric[1m])
{} 3
eval instant at 1m sum_over_time(metric[1m])/count_over_time(metric[1m])
{} 3
eval instant at 1m avg_over_time(metric2[1m])
{} Inf
eval instant at 1m sum_over_time(metric2[1m])/count_over_time(metric2[1m])
{} Inf
eval instant at 1m avg_over_time(metric3[1m])
{} -Inf
eval instant at 1m sum_over_time(metric3[1m])/count_over_time(metric3[1m])
{} -Inf
eval instant at 1m avg_over_time(metric4[1m])
{} NaN
eval instant at 1m sum_over_time(metric4[1m])/count_over_time(metric4[1m])
{} NaN
eval instant at 1m avg_over_time(metric5[1m])
{} Inf
eval instant at 1m sum_over_time(metric5[1m])/count_over_time(metric5[1m])
{} Inf
eval instant at 1m avg_over_time(metric5b[1m])
{} Inf
eval instant at 1m sum_over_time(metric5b[1m])/count_over_time(metric5b[1m])
{} Inf
eval instant at 1m avg_over_time(metric5c[1m])
{} NaN
eval instant at 1m sum_over_time(metric5c[1m])/count_over_time(metric5c[1m])
{} NaN
eval instant at 1m avg_over_time(metric6[1m])
{} -Inf
eval instant at 1m sum_over_time(metric6[1m])/count_over_time(metric6[1m])
{} -Inf
eval instant at 1m avg_over_time(metric6b[1m])
{} -Inf
eval instant at 1m sum_over_time(metric6b[1m])/count_over_time(metric6b[1m])
{} -Inf
eval instant at 1m avg_over_time(metric6c[1m])
{} NaN
eval instant at 1m sum_over_time(metric6c[1m])/count_over_time(metric6c[1m])
{} NaN
eval instant at 1m avg_over_time(metric7[1m])
{} NaN
eval instant at 1m sum_over_time(metric7[1m])/count_over_time(metric7[1m])
{} NaN
eval instant at 1m avg_over_time(metric8[1m])
{} 9.988465674311579e+307
# This overflows float64.
eval instant at 1m sum_over_time(metric8[1m])/count_over_time(metric8[1m])
{} Inf
eval instant at 1m avg_over_time(metric9[1m])
{} -9.988465674311579e+307
# This overflows float64.
eval instant at 1m sum_over_time(metric9[1m])/count_over_time(metric9[1m])
{} -Inf
eval instant at 1m avg_over_time(metric10[1m])
{} 0
eval instant at 1m sum_over_time(metric10[1m])/count_over_time(metric10[1m])
{} 0
# Tests for stddev_over_time and stdvar_over_time.
clear
load 10s