From 9f4bdaab50eaeb09adefe14dd31d4c1c68f5b398 Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" <matt.proud@gmail.com>
Date: Wed, 28 Nov 2012 22:48:28 +0100
Subject: [PATCH] Major LevelDB metric end-to-end test improvements.

Performance is enhanced through better range selection.
---
 storage/metric/leveldb/leveldb.go      |  4 --
 storage/metric/leveldb/leveldb_test.go | 72 ++++++++++++++++----------
 2 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/storage/metric/leveldb/leveldb.go b/storage/metric/leveldb/leveldb.go
index c86bb2ff6..38aba87cc 100644
--- a/storage/metric/leveldb/leveldb.go
+++ b/storage/metric/leveldb/leveldb.go
@@ -16,7 +16,6 @@ package leveldb
 import (
 	"code.google.com/p/goprotobuf/proto"
 	"errors"
-	"fmt"
 	"github.com/matttproud/prometheus/coding"
 	"github.com/matttproud/prometheus/coding/indexable"
 	"github.com/matttproud/prometheus/model"
@@ -447,8 +446,6 @@ func (l *LevelDBMetricPersistence) appendFingerprints(ddo *data.MetricDDO) error
 }
 
 func (l *LevelDBMetricPersistence) AppendSample(sample *model.Sample) error {
-	fmt.Printf("Sample: %q\n", sample)
-
 	metricDDO := ddoFromSample(sample)
 
 	if indexHas, indexHasError := l.hasIndexMetric(metricDDO); indexHasError == nil {
@@ -628,7 +625,6 @@ func (l *LevelDBMetricPersistence) GetWatermarksForMetric(metric model.Metric) (
 										return emission, foundEntries, nil
 									}
 									foundEntries++
-									log.Printf("b foundEntries++ %d\n", foundEntries)
 									emission.NewestInclusive = indexable.DecodeTime(found.Timestamp)
 								} else {
 									log.Printf("Could not de-serialize subsequent key: %q\n", subsequentUnmarshalErr)
diff --git a/storage/metric/leveldb/leveldb_test.go b/storage/metric/leveldb/leveldb_test.go
index 771bcfd9e..f7b937b77 100644
--- a/storage/metric/leveldb/leveldb_test.go
+++ b/storage/metric/leveldb/leveldb_test.go
@@ -27,6 +27,10 @@ import (
 	"time"
 )
 
+const (
+	stochasticMaximumVariance = 64
+)
+
 func TestBasicLifecycle(t *testing.T) {
 	temporaryDirectory, temporaryDirectoryErr := ioutil.TempDir("", "leveldb_metric_persistence_test")
 
@@ -325,13 +329,15 @@ func TestAppendSampleAsPureSingleEntityAppend(t *testing.T) {
 
 func TestStochastic(t *testing.T) {
 	stochastic := func(x int) bool {
+		s := time.Now()
 		seed := rand.NewSource(int64(x))
 		random := rand.New(seed)
-		numberOfMetrics := random.Intn(5) + 1
-		numberOfSharedLabels := random.Intn(5)
-		numberOfUnsharedLabels := random.Intn(5)
-		numberOfSamples := random.Intn(1024) + 2
-		numberOfRangeScans := random.Intn(3)
+
+		numberOfMetrics := random.Intn(stochasticMaximumVariance) + 1
+		numberOfSharedLabels := random.Intn(stochasticMaximumVariance)
+		numberOfUnsharedLabels := random.Intn(stochasticMaximumVariance)
+		numberOfSamples := random.Intn(stochasticMaximumVariance) + 2
+		numberOfRangeScans := random.Intn(stochasticMaximumVariance)
 
 		temporaryDirectory, _ := ioutil.TempDir("", "leveldb_metric_persistence_test")
 
@@ -544,10 +550,6 @@ func TestStochastic(t *testing.T) {
 				return false
 			}
 
-			minimum := metricEarliestSample[metricIndex]
-			maximum := metricNewestSample[metricIndex]
-			spread := maximum - minimum
-
 			for i := 0; i < numberOfRangeScans; i++ {
 				timestamps := metricTimestamps[metricIndex]
 
@@ -555,34 +557,48 @@ func TestStochastic(t *testing.T) {
 				var second int64 = 0
 
 				for {
-					first = minimum + random.Int63n(spread)
-					if _, has := timestamps[first]; has {
-						break
+					firstCandidate := random.Int63n(int64(len(timestamps)))
+					secondCandidate := random.Int63n(int64(len(timestamps)))
+
+					smallest := int64(-1)
+					largest := int64(-1)
+
+					if firstCandidate == secondCandidate {
+						continue
+					} else if firstCandidate > secondCandidate {
+						largest = firstCandidate
+						smallest = secondCandidate
+					} else {
+						largest = secondCandidate
+						smallest = firstCandidate
 					}
+
+					j := int64(0)
+					for i := range timestamps {
+						if j == smallest {
+							first = i
+						} else if j == largest {
+							second = i
+							break
+						}
+						j++
+					}
+
+					break
 				}
 
-				for {
-					second = minimum + random.Int63n(spread)
-					if _, has := timestamps[second]; has && second != first {
-						break
-					}
-				}
+				begin := first
+				end := second
 
-				var begin int64 = 0
-				var end int64 = 0
-
-				if first > second {
-					begin = second
-					end = first
-				} else {
-					begin = first
-					end = second
+				if second < first {
+					begin, end = second, first
 				}
 
 				interval := model.Interval{
 					OldestInclusive: time.Unix(begin, 0),
 					NewestInclusive: time.Unix(end, 0),
 				}
+
 				rangeValues, rangeErr := persistence.GetSamplesForMetric(metric, interval)
 
 				if rangeErr != nil {
@@ -595,6 +611,8 @@ func TestStochastic(t *testing.T) {
 			}
 		}
 
+		fmt.Printf("Duration %q\n", time.Now().Sub(s))
+
 		return true
 	}