Make topk/bottomk prefer returning real numbers over NaN.

This commit is contained in:
Brian Brazil 2015-12-22 13:53:43 +00:00
parent edf3e123f5
commit 88ca82304c
2 changed files with 43 additions and 11 deletions

View File

@ -194,7 +194,7 @@ func funcTopk(ev *evaluator, args Expressions) model.Value {
topk := make(vectorByValueHeap, 0, k) topk := make(vectorByValueHeap, 0, k)
for _, el := range vec { for _, el := range vec {
if len(topk) < k || topk[0].Value < el.Value { if len(topk) < k || topk[0].Value < el.Value || math.IsNaN(float64(topk[0].Value)) {
if len(topk) == k { if len(topk) == k {
heap.Pop(&topk) heap.Pop(&topk)
} }
@ -213,18 +213,17 @@ func funcBottomk(ev *evaluator, args Expressions) model.Value {
} }
vec := ev.evalVector(args[1]) vec := ev.evalVector(args[1])
bottomk := make(vectorByValueHeap, 0, k) bottomk := make(vectorByReverseValueHeap, 0, k)
bkHeap := reverseHeap{Interface: &bottomk}
for _, el := range vec { for _, el := range vec {
if len(bottomk) < k || bottomk[0].Value > el.Value { if len(bottomk) < k || bottomk[0].Value > el.Value || math.IsNaN(float64(bottomk[0].Value)) {
if len(bottomk) == k { if len(bottomk) == k {
heap.Pop(&bkHeap) heap.Pop(&bottomk)
} }
heap.Push(&bkHeap, el) heap.Push(&bottomk, el)
} }
} }
sort.Sort(bottomk) sort.Sort(sort.Reverse(bottomk))
return vector(bottomk) return vector(bottomk)
} }
@ -985,10 +984,31 @@ func (s *vectorByValueHeap) Pop() interface{} {
return el return el
} }
type reverseHeap struct { type vectorByReverseValueHeap vector
heap.Interface
func (s vectorByReverseValueHeap) Len() int {
return len(s)
} }
func (s reverseHeap) Less(i, j int) bool { func (s vectorByReverseValueHeap) Less(i, j int) bool {
return s.Interface.Less(j, i) if math.IsNaN(float64(s[i].Value)) {
return true
}
return s[i].Value > s[j].Value
}
func (s vectorByReverseValueHeap) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s *vectorByReverseValueHeap) Push(x interface{}) {
*s = append(*s, x.(*sample))
}
func (s *vectorByReverseValueHeap) Pop() interface{} {
old := *s
n := len(old)
el := old[n-1]
*s = old[0 : n-1]
return el
} }

View File

@ -200,6 +200,7 @@ clear
load 5m load 5m
http_requests{job="api-server", instance="0", group="production"} 0+10x10 http_requests{job="api-server", instance="0", group="production"} 0+10x10
http_requests{job="api-server", instance="1", group="production"} 0+20x10 http_requests{job="api-server", instance="1", group="production"} 0+20x10
http_requests{job="api-server", instance="2", group="production"} NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
http_requests{job="api-server", instance="0", group="canary"} 0+30x10 http_requests{job="api-server", instance="0", group="canary"} 0+30x10
http_requests{job="api-server", instance="1", group="canary"} 0+40x10 http_requests{job="api-server", instance="1", group="canary"} 0+40x10
http_requests{job="app-server", instance="0", group="production"} 0+50x10 http_requests{job="app-server", instance="0", group="production"} 0+50x10
@ -224,3 +225,14 @@ eval_ordered instant at 50m bottomk(3, http_requests)
eval_ordered instant at 50m bottomk(5, http_requests{group="canary",job="app-server"}) eval_ordered instant at 50m bottomk(5, http_requests{group="canary",job="app-server"})
http_requests{group="canary", instance="0", job="app-server"} 700 http_requests{group="canary", instance="0", job="app-server"} 700
http_requests{group="canary", instance="1", job="app-server"} 800 http_requests{group="canary", instance="1", job="app-server"} 800
# Test NaN is sorted away from the top/bottom.
eval_ordered instant at 50m topk(3, http_requests{job="api-server",group="production"})
http_requests{job="api-server", instance="1", group="production"} 200
http_requests{job="api-server", instance="0", group="production"} 100
http_requests{job="api-server", instance="2", group="production"} NaN
eval_ordered instant at 50m bottomk(3, http_requests{job="api-server",group="production"})
http_requests{job="api-server", instance="0", group="production"} 100
http_requests{job="api-server", instance="1", group="production"} 200
http_requests{job="api-server", instance="2", group="production"} NaN