Choose ranges by retention and min-block-duration

Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>

cmd/tsdb/main.go

@@ -113,8 +113,7 @@ func (b *writeBenchmark) run(cmd *cobra.Command, args []string) {
 	st, err := tsdb.Open(dir, nil, nil, &tsdb.Options{
 		WALFlushInterval:  200 * time.Millisecond,
 		RetentionDuration: 2 * 24 * 60 * 60 * 1000, // 1 days in milliseconds
-		MinBlockDuration:  3 * 60 * 60 * 1000,      // 3 hours in milliseconds
-		MaxBlockDuration:  27 * 60 * 60 * 1000,     // 1 days in milliseconds
+		BlockRanges:       tsdb.ExponentialBlockRanges(int64(2*time.Hour), 3, 5),
 	})
 	if err != nil {
 		exitWithError(err)

compact.go

@@ -30,6 +30,18 @@ import (
 	"github.com/prometheus/tsdb/labels"
 )
 
+// ExponentialBlockRanges returns the time ranges based on the stepSize
+func ExponentialBlockRanges(minSize int64, steps, stepSize int) []int64 {
+	ranges := make([]int64, 0, steps)
+	curRange := minSize
+	for i := 0; i < steps; i++ {
+		ranges = append(ranges, curRange)
+		curRange = curRange * int64(stepSize)
+	}
+
+	return ranges
+}
+
 // Compactor provides compaction against an underlying storage
 // of time series data.
 type Compactor interface {
@@ -91,15 +103,6 @@ type compactorOptions struct {
 }
 
 func newCompactor(dir string, r prometheus.Registerer, l log.Logger, opts *compactorOptions) *compactor {
-	if opts.blockRanges == nil {
-		opts.blockRanges = []int64{
-			int64(2 * time.Hour),
-			int64(6 * time.Hour),
-			int64(24 * time.Hour),
-			int64(72 * time.Hour),  // 3d
-			int64(216 * time.Hour), // 9d
-		}
-	}
 	return &compactor{
 		dir:     dir,
 		opts:    opts,
@@ -161,6 +164,11 @@ func (c *compactor) Plan() ([][]string, error) {
 }
 
 func (c *compactor) selectDirs(ds []dirMeta) []dirMeta {
+	// The way to skip compaction is to not have blockRanges.
+	if len(c.opts.blockRanges) == 1 {
+		return nil
+	}
+
 	return selectRecurse(ds, c.opts.blockRanges)
 }
 
@@ -184,6 +192,8 @@ func selectRecurse(dms []dirMeta, intervals []int64) []dirMeta {
 	// If there are too many blocks, see if a smaller interval will catch them.
 	// i.e, if we have 0-20, 60-80, 80-100; all fall under 0-240, but we'd rather compact 60-100
 	// than all at once.
+	// Again if have 0-1d, 1d-2d, 3-6d we compact 0-1d, 1d-2d to compact it into the 0-3d block instead of compacting all three
+	// This is to honor the boundaries as much as possible.
 	if len(dirs) > 2 {
 		smallerDirs := selectRecurse(dirs, intervals[:len(intervals)-1])
 		if len(smallerDirs) > 1 {
@@ -194,30 +204,29 @@ func selectRecurse(dms []dirMeta, intervals []int64) []dirMeta {
 	return dirs
 }
 
+// splitByRange splits the directories by the time range.
+// for example if we have blocks 0-10, 10-20, 50-60, 90-100 and want to split them into 30 interval ranges
+// splitByRange returns [0-10, 10-20], [50-60], [90-100].
 func splitByRange(ds []dirMeta, tr int64) [][]dirMeta {
-	splitDirs := [][]dirMeta{}
-	t0 := ds[0].meta.MinTime - ds[0].meta.MinTime%tr
-	dirs := []dirMeta{}
+	var splitDirs [][]dirMeta
 
-	for _, dir := range ds {
-		if intervalContains(t0, t0+tr, dir.meta.MinTime) && intervalContains(t0, t0+tr, dir.meta.MaxTime) {
-			dirs = append(dirs, dir)
-			continue
+	for i := 0; i < len(ds); {
+		var group []dirMeta
+		// Compute start of aligned time range of size tr closest to the current block's start.
+		t0 := ds[i].meta.MinTime - (ds[i].meta.MinTime % tr)
+
+		// Add all dirs to the current group that are within [t0, t0+tr].
+		for ; i < len(ds); i++ {
+			if ds[i].meta.MinTime < t0 || ds[i].meta.MaxTime > t0+tr {
+				break
+			}
+			group = append(group, ds[i])
 		}
 
-		if dir.meta.MinTime >= t0+tr {
-			splitDirs = append(splitDirs, dirs)
-			dirs = []dirMeta{}
-			t0 = dir.meta.MinTime - dir.meta.MinTime%tr
-			if intervalContains(t0, t0+tr, dir.meta.MinTime) && intervalContains(t0, t0+tr, dir.meta.MaxTime) {
-				dirs = append(dirs, dir)
+		if len(group) > 0 {
+			splitDirs = append(splitDirs, group)
 		}
 	}
-	}
-
-	if len(dirs) > 0 {
-		splitDirs = append(splitDirs, dirs)
-	}
 
 	return splitDirs
 }

compact_test.go

@@ -1,3 +1,16 @@
+// Copyright 2017 The Prometheus Authors
+// 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 tsdb
 
 import (

db.go

@@ -45,7 +45,7 @@ import (
 var DefaultOptions = &Options{
 	WALFlushInterval:  5 * time.Second,
 	RetentionDuration: 15 * 24 * 60 * 60 * 1000, // 15 days in milliseconds
-	MinBlockDuration:  3 * 60 * 60 * 1000,       // 2 hours in milliseconds
+	BlockRanges:       ExponentialBlockRanges(int64(2*time.Hour), 3, 5),
 	NoLockfile:        false,
 }
 
@@ -57,9 +57,8 @@ type Options struct {
 	// Duration of persisted data to keep.
 	RetentionDuration uint64
 
-	// The timestamp range of head blocks after which they get persisted.
-	// It's the minimum duration of any persisted block.
-	MinBlockDuration uint64
+	// The sizes of the Blocks.
+	BlockRanges []int64
 
 	// NoLockfile disables creation and consideration of a lock file.
 	NoLockfile bool
@@ -223,7 +222,24 @@ func Open(dir string, l log.Logger, r prometheus.Registerer, opts *Options) (db
 		db.lockf = &lockf
 	}
 
-	db.compactor = newCompactor(dir, r, l, &compactorOptions{})
+	copts := &compactorOptions{
+		blockRanges: opts.BlockRanges,
+	}
+
+	if len(copts.blockRanges) == 0 {
+		return nil, errors.New("at least one block-range must exist")
+	}
+
+	for float64(copts.blockRanges[len(copts.blockRanges)-1])/float64(opts.RetentionDuration) > 0.2 {
+		if len(copts.blockRanges) == 1 {
+			break
+		}
+
+		// Max overflow is restricted to 20%.
+		copts.blockRanges = copts.blockRanges[:len(copts.blockRanges)-1]
+	}
+
+	db.compactor = newCompactor(dir, r, l, copts)
 
 	if err := db.reloadBlocks(); err != nil {
 		return nil, err
@@ -693,20 +709,20 @@ func rangeForTimestamp(t int64, width int64) (mint, maxt int64) {
 // it is within or after the currently appendable window.
 func (db *DB) ensureHead(t int64) error {
 	var (
-		mint, maxt = rangeForTimestamp(t, int64(db.opts.MinBlockDuration))
+		mint, maxt = rangeForTimestamp(t, int64(db.opts.BlockRanges[0]))
 		addBuffer  = len(db.blocks) == 0
 		last       BlockMeta
 	)
 
 	if !addBuffer {
 		last = db.blocks[len(db.blocks)-1].Meta()
-		addBuffer = last.MaxTime <= mint-int64(db.opts.MinBlockDuration)
+		addBuffer = last.MaxTime <= mint-int64(db.opts.BlockRanges[0])
 	}
 	// Create another block of buffer in front if the DB is initialized or retrieving
 	// new data after a long gap.
 	// This ensures we always have a full block width if append window.
 	if addBuffer {
-		if _, err := db.createHeadBlock(mint-int64(db.opts.MinBlockDuration), mint); err != nil {
+		if _, err := db.createHeadBlock(mint-int64(db.opts.BlockRanges[0]), mint); err != nil {
 			return err
 		}
 		// If the previous block reaches into our new window, make it smaller.