Simplify compaction and expose database sizes.

This commit simplifies the way that compactions across a database's
keyspace occur due to reading the LevelDB internals. Secondarily it
introduces the database size estimation mechanisms.

Include database health and help interfaces.

Add database statistics; remove status goroutines.

This commit kills the use of Go routines to expose status throughout
the web components of Prometheus. It also dumps raw LevelDB status
on a separate /databases endpoint.

README.md

@@ -1,3 +1,4 @@
+
 # Prometheus
 
 Bedecke deinen Himmel, Zeus!  A new kid is in town.

main.go

@@ -20,6 +20,7 @@ import (
 	"github.com/prometheus/prometheus/retrieval/format"
 	"github.com/prometheus/prometheus/rules"
 	"github.com/prometheus/prometheus/storage/metric"
+	"github.com/prometheus/prometheus/storage/raw/leveldb"
 	"github.com/prometheus/prometheus/web"
 	"github.com/prometheus/prometheus/web/api"
 	"log"
@@ -66,8 +67,10 @@ type prometheus struct {
 	bodyCompactionTimer      *time.Ticker
 	tailCompactionTimer      *time.Ticker
 	deletionTimer            *time.Ticker
+	reportDatabasesTimer     *time.Ticker
 	curationMutex            sync.Mutex
 	curationState            chan metric.CurationState
+	databaseStates           chan []leveldb.DatabaseState
 	stopBackgroundOperations chan bool
 
 	ruleResults   chan *rules.Result
@@ -132,6 +135,10 @@ func (p *prometheus) close() {
 		p.deletionTimer.Stop()
 	}
 
+	if p.reportDatabasesTimer != nil {
+		p.reportDatabasesTimer.Stop()
+	}
+
 	if len(p.stopBackgroundOperations) == 0 {
 		p.stopBackgroundOperations <- true
 	}
@@ -141,6 +148,26 @@ func (p *prometheus) close() {
 	p.storage.Close()
 	close(p.stopBackgroundOperations)
 	close(p.curationState)
+	close(p.databaseStates)
+}
+
+func (p *prometheus) reportDatabaseState() {
+	for _ = range p.reportDatabasesTimer.C {
+		// BUG(matt): Per Julius, ...
+		// These channel magic tricks confuse me and seem a bit awkward just to
+		// pass a status around. Now that we have Go 1.1, would it be maybe be
+		// nicer to pass ts.DiskStorage.States as a method value
+		// (http://tip.golang.org/ref/spec#Method_values) to the web layer
+		// instead of doing this?
+		select {
+		case <-p.databaseStates:
+			// Reset the future database state if nobody consumes it.
+		case p.databaseStates <- p.storage.DiskStorage.States():
+			// Set the database state so someone can consume it if they want.
+		default:
+			// Don't block.
+		}
+	}
 }
 
 func main() {
@@ -171,6 +198,7 @@ func main() {
 	scrapeResults := make(chan format.Result, *scrapeResultsQueueCapacity)
 	ruleResults := make(chan *rules.Result, *ruleResultsQueueCapacity)
 	curationState := make(chan metric.CurationState, 1)
+	databaseStates := make(chan []leveldb.DatabaseState, 1)
 	// Coprime numbers, fool!
 	headCompactionTimer := time.NewTicker(*headCompactInterval)
 	bodyCompactionTimer := time.NewTicker(*bodyCompactInterval)
@@ -181,17 +209,25 @@ func main() {
 	targetManager := retrieval.NewTargetManager(scrapeResults, *concurrentRetrievalAllowance)
 	targetManager.AddTargetsFromConfig(conf)
 
+	flags := map[string]string{}
+
+	flag.VisitAll(func(f *flag.Flag) {
+		flags[f.Name] = f.Value.String()
+	})
+
 	statusHandler := &web.StatusHandler{
-		BuildInfo:     BuildInfo,
-		Config:        &conf,
+		PrometheusStatus: &web.PrometheusStatus{
+			BuildInfo:   BuildInfo,
+			Config:      conf.String(),
+			TargetPools: targetManager.Pools(),
+			Flags:       flags,
+		},
 		CurationState: curationState,
-		// Furnish the default status.
-		PrometheusStatus: &web.PrometheusStatus{},
-		TargetManager:    targetManager,
 	}
 
-	// The closing of curationState implicitly closes this routine.
-	go statusHandler.ServeRequestsForever()
+	databasesHandler := &web.DatabasesHandler{
+		Incoming: databaseStates,
+	}
 
 	metricsService := &api.MetricsService{
 		Config:        &conf,
@@ -200,8 +236,9 @@ func main() {
 	}
 
 	webService := &web.WebService{
-		StatusHandler:  statusHandler,
-		MetricsHandler: metricsService,
+		StatusHandler:    statusHandler,
+		MetricsHandler:   metricsService,
+		DatabasesHandler: databasesHandler,
 	}
 
 	prometheus := prometheus{
@@ -211,7 +248,11 @@ func main() {
 
 		deletionTimer: deletionTimer,
 
-		curationState: curationState,
+		reportDatabasesTimer: time.NewTicker(15 * time.Minute),
+
+		curationState:  curationState,
+		databaseStates: databaseStates,
+
 		ruleResults:   ruleResults,
 		scrapeResults: scrapeResults,
 
@@ -223,6 +264,7 @@ func main() {
 
 	go ts.Serve()
 	go prometheus.interruptHandler()
+	go prometheus.reportDatabaseState()
 
 	go func() {
 		for _ = range prometheus.headCompactionTimer.C {

storage/metric/curator.go

@@ -119,9 +119,8 @@ func (c Curator) Run(ignoreYoungerThan time.Duration, instant time.Time, process
 	}(time.Now())
 	defer func() {
 		select {
-		case status <- CurationState{
-			Active: false,
-		}:
+		case status <- CurationState{Active: false}:
+		case <-status:
 		default:
 		}
 	}()
@@ -268,6 +267,7 @@ func (w watermarkFilter) Filter(key, value interface{}) (r storage.FilterResult)
 			Limit:       w.ignoreYoungerThan,
 			Fingerprint: fingerprint,
 		}:
+		case <-w.status:
 		default:
 		}
 	}()

storage/metric/leveldb.go

@@ -22,7 +22,7 @@ import (
 	dto "github.com/prometheus/prometheus/model/generated"
 	"github.com/prometheus/prometheus/storage"
 	index "github.com/prometheus/prometheus/storage/raw/index/leveldb"
-	leveldb "github.com/prometheus/prometheus/storage/raw/leveldb"
+	"github.com/prometheus/prometheus/storage/raw/leveldb"
 	"github.com/prometheus/prometheus/utility"
 	"log"
 	"sort"
@@ -931,3 +931,44 @@ func (l *LevelDBMetricPersistence) ApproximateSizes() (total uint64, err error)
 
 	return total, nil
 }
+
+func (l *LevelDBMetricPersistence) States() []leveldb.DatabaseState {
+	states := []leveldb.DatabaseState{}
+
+	state := l.CurationRemarks.State()
+	state.Name = "Curation Remarks"
+	state.Type = "Watermark"
+	states = append(states, state)
+
+	state = l.fingerprintToMetrics.State()
+	state.Name = "Fingerprints to Metrics"
+	state.Type = "Index"
+	states = append(states, state)
+
+	state = l.labelNameToFingerprints.State()
+	state.Name = "Label Name to Fingerprints"
+	state.Type = "Inverted Index"
+	states = append(states, state)
+
+	state = l.labelSetToFingerprints.State()
+	state.Name = "Label Pair to Fingerprints"
+	state.Type = "Inverted Index"
+	states = append(states, state)
+
+	state = l.MetricHighWatermarks.State()
+	state.Name = "Metric Last Write"
+	state.Type = "Watermark"
+	states = append(states, state)
+
+	state = l.metricMembershipIndex.State()
+	state.Name = "Metric Membership"
+	state.Type = "Index"
+	states = append(states, state)
+
+	state = l.MetricSamples.State()
+	state.Name = "Samples"
+	state.Type = "Time Series"
+	states = append(states, state)
+
+	return states
+}

storage/metric/tiered.go

@@ -59,20 +59,27 @@ type TieredStorage struct {
 	// BUG(matt): This introduces a Law of Demeter violation.  Ugh.
 	DiskStorage *LevelDBMetricPersistence
 
-	appendToDiskQueue   chan model.Samples
-	diskFrontier        *diskFrontier
-	draining            chan chan bool
-	flushMemoryInterval time.Duration
+	appendToDiskQueue chan model.Samples
+
+	diskFrontier *diskFrontier
+
 	memoryArena         memorySeriesStorage
 	memoryTTL           time.Duration
+	flushMemoryInterval time.Duration
+	writeMemoryInterval time.Duration
+
 	// This mutex manages any concurrent reads/writes of the memoryArena.
 	memoryMutex sync.RWMutex
 	// This mutex blocks only deletions from the memoryArena. It is held for a
 	// potentially long time for an entire renderView() duration, since we depend
 	// on no samples being removed from memory after grabbing a LevelDB snapshot.
-	memoryDeleteMutex   sync.RWMutex
-	viewQueue           chan viewJob
-	writeMemoryInterval time.Duration
+	memoryDeleteMutex sync.RWMutex
+
+	viewQueue chan viewJob
+
+	draining chan chan bool
+
+	mutex sync.Mutex
 }
 
 // viewJob encapsulates a request to extract sample values from the datastore.
@@ -180,11 +187,13 @@ func (t *TieredStorage) rebuildDiskFrontier(i leveldb.Iterator) (err error) {
 func (t *TieredStorage) Serve() {
 	flushMemoryTicker := time.NewTicker(t.flushMemoryInterval)
 	defer flushMemoryTicker.Stop()
-	reportTicker := time.NewTicker(time.Second)
-	defer reportTicker.Stop()
+	writeMemoryTicker := time.NewTicker(t.writeMemoryInterval)
+	defer writeMemoryTicker.Stop()
+	queueReportTicker := time.NewTicker(time.Second)
+	defer queueReportTicker.Stop()
 
 	go func() {
-		for _ = range reportTicker.C {
+		for _ = range queueReportTicker.C {
 			t.reportQueues()
 		}
 	}()

storage/raw/index/leveldb/leveldb.go

@@ -73,3 +73,7 @@ func (l *LevelDBMembershipIndex) CompactKeyspace() {
 func (l *LevelDBMembershipIndex) ApproximateSize() (uint64, error) {
 	return l.persistence.ApproximateSize()
 }
+
+func (l *LevelDBMembershipIndex) State() leveldb.DatabaseState {
+	return l.persistence.State()
+}

storage/raw/leveldb/leveldb.go

@@ -31,6 +31,8 @@ var (
 
 // LevelDBPersistence is a disk-backed sorted key-value store.
 type LevelDBPersistence struct {
+	path string
+
 	cache        *levigo.Cache
 	filterPolicy *levigo.FilterPolicy
 	options      *levigo.Options
@@ -67,11 +69,9 @@ type levigoIterator struct {
 }
 
 func (i levigoIterator) String() string {
-	var (
-		valid       = "valid"
-		open        = "open"
-		snapshotted = "snapshotted"
-	)
+	valid := "valid"
+	open := "open"
+	snapshotted := "snapshotted"
 
 	if i.closed {
 		open = "closed"
@@ -193,6 +193,8 @@ func NewLevelDBPersistence(storageRoot string, cacheCapacity, bitsPerBloomFilter
 
 	writeOptions.SetSync(*leveldbFlushOnMutate)
 	p = &LevelDBPersistence{
+		path: storageRoot,
+
 		cache:        cache,
 		filterPolicy: filterPolicy,
 

storage/raw/leveldb/state.go

@@ -0,0 +1,54 @@
+// 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 leveldb
+
+import (
+	"github.com/prometheus/prometheus/utility"
+	"time"
+)
+
+const (
+	statsKey    = "leveldb.stats"
+	sstablesKey = "leveldb.sstables"
+)
+
+// DatabaseState models a bundle of metadata about a LevelDB database used in
+// template format string interpolation.
+type DatabaseState struct {
+	LastRefreshed   time.Time
+	Type            string
+	Name            string
+	Path            string
+	LowLevelStatus  string
+	SSTablesStatus  string
+	ApproximateSize utility.ByteSize
+	Error           error
+}
+
+func (l *LevelDBPersistence) State() DatabaseState {
+	databaseState := DatabaseState{
+		LastRefreshed:  time.Now(),
+		Path:           l.path,
+		LowLevelStatus: l.storage.PropertyValue(statsKey),
+		SSTablesStatus: l.storage.PropertyValue(sstablesKey),
+	}
+
+	if size, err := l.ApproximateSize(); err != nil {
+		databaseState.Error = err
+	} else {
+		databaseState.ApproximateSize = utility.ByteSize(size)
+	}
+
+	return databaseState
+}

utility/bytesize.go

@@ -0,0 +1,55 @@
+// 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 utility
+
+import (
+	"fmt"
+)
+
+// The canonical example: http://golang.org/doc/progs/eff_bytesize.go.
+type ByteSize float64
+
+const (
+	_           = iota // ignore first value by assigning to blank identifier
+	KB ByteSize = 1 << (10 * iota)
+	MB
+	GB
+	TB
+	PB
+	EB
+	ZB
+	YB
+)
+
+func (b ByteSize) String() string {
+	switch {
+	case b >= YB:
+		return fmt.Sprintf("%.2fYB", b/YB)
+	case b >= ZB:
+		return fmt.Sprintf("%.2fZB", b/ZB)
+	case b >= EB:
+		return fmt.Sprintf("%.2fEB", b/EB)
+	case b >= PB:
+		return fmt.Sprintf("%.2fPB", b/PB)
+	case b >= TB:
+		return fmt.Sprintf("%.2fTB", b/TB)
+	case b >= GB:
+		return fmt.Sprintf("%.2fGB", b/GB)
+	case b >= MB:
+		return fmt.Sprintf("%.2fMB", b/MB)
+	case b >= KB:
+		return fmt.Sprintf("%.2fKB", b/KB)
+	}
+	return fmt.Sprintf("%.2fB", b)
+}

web/databases.go

@@ -0,0 +1,42 @@
+// 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 web
+
+import (
+	"github.com/prometheus/prometheus/storage/raw/leveldb"
+	"net/http"
+	"sync"
+)
+
+type DatabasesHandler struct {
+	States []leveldb.DatabaseState
+
+	Incoming chan []leveldb.DatabaseState
+
+	mutex sync.RWMutex
+}
+
+func (h *DatabasesHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	select {
+	case states := <-h.Incoming:
+		h.mutex.Lock()
+		defer h.mutex.Unlock()
+		h.States = states
+	default:
+		h.mutex.RLock()
+		defer h.mutex.RUnlock()
+	}
+
+	executeTemplate(w, "databases", h)
+}

web/static/css/prometheus.css

@@ -79,3 +79,7 @@ input[name=end_input], input[name=range_input] {
 #add_graph {
     margin-left: 8px;
 }
+
+.literal_output td {
+  font-family: monospace;
+}

web/status.go

@@ -14,8 +14,6 @@
 package web
 
 import (
-	"flag"
-	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/retrieval"
 	"github.com/prometheus/prometheus/storage/metric"
 	"net/http"
@@ -32,39 +30,22 @@ type PrometheusStatus struct {
 }
 
 type StatusHandler struct {
-	sync.Mutex
-	BuildInfo        map[string]string
-	Config           *config.Config
 	CurationState    chan metric.CurationState
 	PrometheusStatus *PrometheusStatus
-	TargetManager    retrieval.TargetManager
-}
 
-func (h *StatusHandler) ServeRequestsForever() {
-	flags := map[string]string{}
-
-	flag.VisitAll(func(f *flag.Flag) {
-		flags[f.Name] = f.Value.String()
-	})
-
-	h.PrometheusStatus = &PrometheusStatus{
-		BuildInfo: h.BuildInfo,
-		Config:    h.Config.String(),
-		Flags:     flags,
-		Rules:     "TODO: list rules here",
-		// BUG: race condition, concurrent map access
-		TargetPools: h.TargetManager.Pools(),
-	}
-
-	for state := range h.CurationState {
-		h.Lock()
-		h.PrometheusStatus.Curation = state
-		h.Unlock()
-	}
+	mutex sync.RWMutex
 }
 
 func (h *StatusHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	h.Lock()
-	defer h.Unlock()
+	select {
+	case curationState := <-h.CurationState:
+		h.mutex.Lock()
+		defer h.mutex.Unlock()
+		h.PrometheusStatus.Curation = curationState
+	default:
+		h.mutex.RLock()
+		defer h.mutex.RUnlock()
+	}
+
 	executeTemplate(w, "status", h.PrometheusStatus)
 }

web/templates/_base.html

@@ -2,7 +2,7 @@
 <html lang="en">
   <head>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-    <title>Prometheus</title>
+    <title>Prometheus Time Series Collection and Processing Server</title>
     <script src="/static/vendor/js/jquery.min.js"></script>
     <link type="text/css" rel="stylesheet" href="/static/css/prometheus.css">
     {{template "head" .}}
@@ -10,8 +10,12 @@
 
   <body>
     <div id="navigation">
-      <a href="/graph">Graph</a>
+      <a href="/graph">Graph &amp; Console</a>
       <a href="/">Status</a>
+      <a href="/databases">Databases</a>
+
+      <!-- Help should preferentially be the right-most element. -->
+      <a href="https://github.com/prometheus/prometheus/wiki" target="_blank">Help</a>
     </div>
     {{template "content" .}}
   </body>

web/web.go

@@ -34,8 +34,9 @@ var (
 )
 
 type WebService struct {
-	StatusHandler  *StatusHandler
-	MetricsHandler *api.MetricsService
+	StatusHandler    *StatusHandler
+	DatabasesHandler *DatabasesHandler
+	MetricsHandler   *api.MetricsService
 }
 
 func (w WebService) ServeForever() error {
@@ -53,6 +54,7 @@ func (w WebService) ServeForever() error {
 	exp.Handle("/debug/pprof/symbol", http.HandlerFunc(pprof.Symbol))
 
 	exp.Handle("/", w.StatusHandler)
+	exp.Handle("/databases", w.DatabasesHandler)
 	exp.HandleFunc("/graph", graphHandler)
 
 	exp.Handle("/api/", gorest.Handle())