Expose interfaces for pruner and make pruner tool.

In order to run database cleanups and diagnostics, we should have
a means for pruning a database---even if LevelDB does this for us.

Makefile

@@ -23,12 +23,13 @@ advice:
 binary: build
 	go build $(BUILDFLAGS) .
 
-build: preparation config model web
+build: preparation config model tools web
 
 clean:
 	$(MAKE) -C build clean
 	$(MAKE) -C config clean
 	$(MAKE) -C model clean
+	$(MAKE) -C tools clean
 	$(MAKE) -C web clean
 	rm -rf $(TEST_ARTIFACTS)
 	-find . -type f -iname '*~' -exec rm '{}' ';'
@@ -72,7 +73,10 @@ source_path:
 test: build
 	go test ./... $(GO_TEST_FLAGS)
 
+tools:
+	$(MAKE) -C tools
+
 web: preparation config model
 	$(MAKE) -C web
 
-.PHONY: advice binary build clean config documentation format model package preparation run search_index source_path test
+.PHONY: advice binary build clean config documentation format model package preparation run search_index source_path test tools

storage/metric/leveldb.go

@@ -876,3 +876,35 @@ func (l *LevelDBMetricPersistence) GetAllValuesForLabel(labelName model.LabelNam
 func (l *LevelDBMetricPersistence) ForEachSample(builder IteratorsForFingerprintBuilder) (err error) {
 	panic("not implemented")
 }
+
+// CompactKeyspace compacts each database's keyspace serially.  An error may
+// be returned if there are difficulties with the underlying database or if
+// it's empty.
+//
+// Beware that it would probably be imprudent to run this on a live user-facing
+// server due to latency implications.
+func (l *LevelDBMetricPersistence) CompactKeyspaces() error {
+	if err := l.CurationRemarks.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact curation remarks: %s", err)
+	}
+	if err := l.fingerprintToMetrics.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact fingerprint to metric index: %s", err)
+	}
+	if err := l.labelNameToFingerprints.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact label name to fingerprint index: %s", err)
+	}
+	if err := l.labelSetToFingerprints.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact label pair to fingerprint index: %s", err)
+	}
+	if err := l.MetricHighWatermarks.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact metric high watermarks: %s", err)
+	}
+	if err := l.metricMembershipIndex.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact metric membership index: %s", err)
+	}
+	if err := l.MetricSamples.CompactKeyspace(); err != nil {
+		return fmt.Errorf("Could not compact metric samples database: %s", err)
+	}
+
+	return nil
+}

storage/raw/index/leveldb/leveldb.go

@@ -61,3 +61,13 @@ func NewLevelDBMembershipIndex(storageRoot string, cacheCapacity, bitsPerBloomFi
 func (l *LevelDBMembershipIndex) Commit(batch raw.Batch) error {
 	return l.persistence.Commit(batch)
 }
+
+// CompactKeyspace compacts the entire database's keyspace.  An error may be
+// returned if there are difficulties with the underlying database or if it's
+// empty.
+//
+// Beware that it would probably be imprudent to run this on a live user-facing
+// server due to latency implications.
+func (l *LevelDBMembershipIndex) CompactKeyspace() error {
+	return l.persistence.CompactKeyspace()
+}

storage/raw/leveldb/leveldb.go

@@ -195,10 +195,12 @@ func NewLevelDBPersistence(storageRoot string, cacheCapacity, bitsPerBloomFilter
 	p = &LevelDBPersistence{
 		cache:        cache,
 		filterPolicy: filterPolicy,
+
 		options:      options,
 		readOptions:  readOptions,
-		storage:      storage,
 		writeOptions: writeOptions,
+
+		storage: storage,
 	}
 
 	return
@@ -306,6 +308,35 @@ func (l *LevelDBPersistence) Commit(b raw.Batch) (err error) {
 	return l.storage.Write(l.writeOptions, batch.batch)
 }
 
+// CompactKeyspace compacts the entire database's keyspace.  An error may be
+// returned if there are difficulties with the underlying database or if it's
+// empty.
+//
+// Beware that it would probably be imprudent to run this on a live user-facing
+// server due to latency implications.
+func (l *LevelDBPersistence) CompactKeyspace() error {
+	iterator := l.NewIterator(false)
+	defer iterator.Close()
+
+	if !iterator.SeekToFirst() {
+		return fmt.Errorf("could not seek to first key")
+	}
+
+	keyspace := levigo.Range{}
+
+	keyspace.Start = iterator.Key()
+
+	if !iterator.SeekToLast() {
+		return fmt.Errorf("could not seek to last key")
+	}
+
+	keyspace.Limit = iterator.Key()
+
+	l.storage.CompactRange(keyspace)
+
+	return nil
+}
+
 // NewIterator creates a new levigoIterator, which follows the Iterator
 // interface.
 //

tools/Makefile

@@ -0,0 +1,26 @@
+# 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.
+
+all: pruner
+
+SUFFIXES:
+
+include ../Makefile.INCLUDE
+
+pruner:
+	$(MAKE) -C pruner
+
+clean:
+	$(MAKE) -C pruner clean
+
+.PHONY: clean pruner

tools/pruner/.gitignore

@@ -0,0 +1 @@
+pruner

tools/pruner/Makefile

@@ -0,0 +1,28 @@
+# 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.
+
+MAKE_ARTIFACTS = pruner
+
+all: pruner
+
+SUFFIXES:
+
+include ../../Makefile.INCLUDE
+
+pruner: $(shell find . -iname '*.go')
+	go build -o pruner .
+
+clean:
+	rm -rf $(MAKE_ARTIFACTS)
+
+.PHONY: clean

tools/pruner/main.go

@@ -0,0 +1,49 @@
+// 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.
+
+// Pruner is responsible for cleaning all Prometheus disk databases, which
+// minimally includes 1. applying pending commit logs, 2. compacting SSTables,
+// 3. purging stale SSTables, and 4. removing old tombstones.
+package main
+
+import (
+	"flag"
+	"github.com/prometheus/prometheus/storage/metric"
+	"log"
+	"time"
+)
+
+var (
+	storageRoot = flag.String("storage.root", "", "The path to the storage root for Prometheus.")
+)
+
+func main() {
+	flag.Parse()
+
+	if storageRoot == nil || *storageRoot == "" {
+		log.Fatal("Must provide a path...")
+	}
+
+	persistences, err := metric.NewLevelDBMetricPersistence(*storageRoot)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer persistences.Close()
+
+	start := time.Now()
+	log.Printf("Starting compaction...")
+	if err := persistences.CompactKeyspaces(); err != nil {
+		log.Fatalf("Abording after %s", time.Since(start))
+	}
+	log.Printf("Finished in %s", time.Since(start))
+}