// Get history values for the input metric, will only fetch the history
// values with the same phase around this timestamp, within an filter
// offset.
func (d *Detector) values(m *models.Metric, fz bool) ([]float64, error) {
timer := util.NewTimer()
defer func() {
elapsed := timer.Elapsed()
health.AddQueryCost(elapsed)
}()
offset := uint32(d.cfg.Detector.FilterOffset * float64(d.cfg.Period))
expiration := d.cfg.Expiration
period := d.cfg.Period
ftimes := d.cfg.Detector.FilterTimes
// Get values with the same phase.
n := 0 // number of goroutines to luanch
ch := make(chan metricGetResult)
var stamp uint32
if d.cfg.Detector.UsingRecentDataPoints {
stamp = m.Stamp
} else {
stamp = m.Stamp - period
}
for ; stamp+expiration > m.Stamp; stamp -= period {
start := stamp - offset
stop := stamp + offset
// Range (m.Stamp,m.Stamp+offset) has no data as it is the future
if stamp == m.Stamp {
stop = m.Stamp
}
go func() {
ms, err := d.db.Metric.Get(m.Name, m.Link, start, stop)
ch <- metricGetResult{err, ms, start, stop}
}()
n++
if n >= ftimes {
break
}
}
// Concat chunks.
var vals []float64
var err error
for i := 0; i < n; i++ {
r := <-ch
if r.err != nil {
// Record error but DONOT return directly.
// Must receive n times from ch, otherwise the goroutine will
// be hanged and the ch won't be gc, yet memory leaks.
err = r.err
continue
}
if err != nil {
continue
}
// Append to values.
if !fz {
for j := 0; j < len(r.ms); j++ {
vals = append(vals, r.ms[j].Value)
}
} else {
// Fill blank with zeros.
vals = append(vals, d.fill0(r.ms, r.start, r.stop)...)
}
}
return vals, err
}
// Get history values for the input metric, will only fetch the history
// values with the same phase around this timestamp, within an filter
// offset.
func (d *Detector) values(m *models.Metric, fz bool) ([]float64, error) {
timer := util.NewTimer()
defer func() {
elapsed := timer.Elapsed()
health.AddQueryCost(elapsed)
}()
offset := uint32(d.cfg.Detector.FilterOffset * float64(d.cfg.Period))
expiration := d.cfg.Expiration
period := d.cfg.Period
ftimes := d.cfg.Detector.FilterTimes
k := int(math.Ceil(float64(expiration) / float64(period)))
s := rand.Perm(k)[:ftimes]
mp := make(map[int]bool, ftimes)
for _, v := range s {
mp[v] = true
}
// Get values with the same phase.
n := 0 // number of goroutines to luanch
i := 0 // index of the following loop
ch := make(chan metricGetResult)
for stamp := m.Stamp; stamp+expiration > m.Stamp; stamp -= period {
start := stamp - offset
stop := stamp + offset
if mp[i] {
go func() {
ms, err := d.db.Metric.Get(m.Name, start, stop)
ch <- metricGetResult{err, ms, start, stop}
}()
n++
}
i++
}
// Concat chunks.
var vals []float64
var err error
for i := 0; i < n; i++ {
r := <-ch
if r.err != nil {
// Record error but DONOT return directly.
// Must receive n times from ch, otherwise the goroutine will
// be hanged and the ch won't be gc, yet memory leaks.
err = r.err
continue
}
if err != nil {
continue
}
// Append to values.
if !fz {
for j := 0; j < len(r.ms); j++ {
vals = append(vals, r.ms[j].Value)
}
} else {
// Fill blank with zeros.
vals = append(vals, d.fill0(r.ms, r.start, r.stop)...)
}
}
if err != nil {
// Unexcepted error
return vals, err
}
// Append m
vals = append(vals, m.Value)
return vals, nil
}