prometheus/stats/timer.go
Julius Volz 51689d965d Add debug timers to instant and range queries.
This adds timers around several query-relevant code blocks. For now, the
query timer stats are only logged for queries initiated through the UI.
In other cases (rule evaluations), the stats are simply thrown away.

My hope is that this helps us understand where queries spend time,
especially in cases where they sometimes hang for unusual amounts of
time.
2013-06-05 18:32:54 +02:00

101 lines
2.3 KiB
Go

// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package stats
import (
"bytes"
"fmt"
"sort"
"time"
)
// A timer that can be started and stopped and accumulates the total time it
// was running (the time between Start() and Stop()).
type Timer struct {
name fmt.Stringer
created time.Time
start time.Time
duration time.Duration
}
// Start the timer.
func (t *Timer) Start() *Timer {
t.start = time.Now()
return t
}
// Stop the timer.
func (t *Timer) Stop() {
t.duration += time.Since(t.start)
}
// Return a string representation of the Timer.
func (t *Timer) String() string {
return fmt.Sprintf("%s: %s", t.name, t.duration)
}
// A TimerGroup represents a group of timers relevant to a single query.
type TimerGroup struct {
timers map[fmt.Stringer]*Timer
child *TimerGroup
}
// Construct a new TimerGroup.
func NewTimerGroup() *TimerGroup {
return &TimerGroup{timers: map[fmt.Stringer]*Timer{}}
}
// Get (and create, if necessary) the Timer for a given code section.
func (t *TimerGroup) GetTimer(name fmt.Stringer) *Timer {
if timer, exists := t.timers[name]; exists {
return timer
}
timer := &Timer{
name: name,
created: time.Now(),
}
t.timers[name] = timer
return timer
}
type Timers []*Timer
type byCreationTimeSorter struct{ Timers }
func (t Timers) Len() int {
return len(t)
}
func (t Timers) Swap(i, j int) {
t[i], t[j] = t[j], t[i]
}
func (s byCreationTimeSorter) Less(i, j int) bool {
return s.Timers[i].created.Before(s.Timers[j].created)
}
// Return a string representation of a TimerGroup.
func (t *TimerGroup) String() string {
timers := byCreationTimeSorter{}
for _, timer := range t.timers {
timers.Timers = append(timers.Timers, timer)
}
sort.Sort(timers)
result := &bytes.Buffer{}
for _, timer := range timers.Timers {
fmt.Fprintf(result, "%s\n", timer)
}
return result.String()
}