feat(wal): Add sizing information to writer and reader.

pkg/storage/wal/chunks/chunks_test.go

@@ -1,18 +1,16 @@
 package chunks
 
 import (
-	"bufio"
 	"bytes"
 	"fmt"
-	"os"
-	"path/filepath"
 	"strconv"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/require"
 
 	"github.com/grafana/loki/v3/pkg/logproto"
+	"github.com/grafana/loki/v3/pkg/storage/wal/testdata"
 )
 
 func TestChunkReaderWriter(t *testing.T) {
@@ -121,11 +119,11 @@ func TestChunkReaderWriter(t *testing.T) {
 }
 
 func TestChunkReaderWriterWithLogGenerator(t *testing.T) {
-	filenames := testDataFile()
+	filenames := testdata.Files()
 
 	for _, filename := range filenames {
 		t.Run(filename, func(t *testing.T) {
-			gen := newLogGenerator(t, filename)
+			gen := testdata.NewLogGenerator(t, filename)
 			defer gen.Close()
 
 			var entries []*logproto.Entry
@@ -196,10 +194,10 @@ var (
 
 // Benchmark reads with log generator
 func BenchmarkReadChunkWithLogGenerator(b *testing.B) {
-	filenames := testDataFile()
+	filenames := testdata.Files()
 	for _, filename := range filenames {
 		b.Run(filename, func(b *testing.B) {
-			gen := newLogGenerator(b, filename)
+			gen := testdata.NewLogGenerator(b, filename)
 			defer gen.Close()
 
 			var entries []*logproto.Entry
@@ -239,12 +237,12 @@ func BenchmarkReadChunkWithLogGenerator(b *testing.B) {
 
 // Benchmark with log generator
 func BenchmarkWriteChunkWithLogGenerator(b *testing.B) {
-	filenames := testDataFile()
+	filenames := testdata.Files()
 
 	for _, filename := range filenames {
 		for _, count := range []int{1000, 10000, 100000} {
 			b.Run(fmt.Sprintf("%s-%d", filename, count), func(b *testing.B) {
-				gen := newLogGenerator(b, filename)
+				gen := testdata.NewLogGenerator(b, filename)
 				defer gen.Close()
 
 				var entries []*logproto.Entry
@@ -278,24 +276,6 @@ func BenchmarkWriteChunkWithLogGenerator(b *testing.B) {
 	}
 }
 
-func testDataFile() []string {
-	testdataDir := "../testdata"
-	files, err := os.ReadDir(testdataDir)
-	if err != nil {
-		panic(err)
-	}
-
-	var fileNames []string
-	for _, file := range files {
-		if !file.IsDir() {
-			filePath := filepath.Join(testdataDir, file.Name())
-			fileNames = append(fileNames, filePath)
-		}
-	}
-
-	return fileNames
-}
-
 // generateLogEntries generates a slice of logproto.Entry with the given count.
 func generateLogEntries(count int) []*logproto.Entry {
 	entries := make([]*logproto.Entry, count)
@@ -307,39 +287,3 @@ func generateLogEntries(count int) []*logproto.Entry {
 	}
 	return entries
 }
-
-type logGenerator struct {
-	f *os.File
-	s *bufio.Scanner
-}
-
-func (g *logGenerator) Next() (bool, []byte) {
-	if g.s.Scan() {
-		return true, g.s.Bytes()
-	}
-	g.reset()
-	return g.s.Scan(), g.s.Bytes()
-}
-
-func (g *logGenerator) Close() {
-	if g.f != nil {
-		g.f.Close()
-	}
-	g.f = nil
-}
-
-func (g *logGenerator) reset() {
-	_, _ = g.f.Seek(0, 0)
-	g.s = bufio.NewScanner(g.f)
-}
-
-func newLogGenerator(t testing.TB, filename string) *logGenerator {
-	t.Helper()
-	file, err := os.Open(filename)
-	require.NoError(t, err)
-
-	return &logGenerator{
-		f: file,
-		s: bufio.NewScanner(file),
-	}
-}

pkg/storage/wal/segment.go

@@ -37,8 +37,9 @@ type streamID struct {
 }
 
 type SegmentWriter struct {
-	streams *swiss.Map[streamID, *streamSegment]
-	buf1    encoding.Encbuf
+	streams   *swiss.Map[streamID, *streamSegment]
+	buf1      encoding.Encbuf
+	inputSize int64
 }
 
 type streamSegment struct {
@@ -61,6 +62,9 @@ func (b *SegmentWriter) Append(tenantID, labelsString string, lbls labels.Labels
 	if len(entries) == 0 {
 		return
 	}
+	for _, e := range entries {
+		b.inputSize += int64(len(e.Line))
+	}
 	id := streamID{labels: labelsString, tenant: tenantID}
 	s, ok := b.streams.Get(id)
 	if !ok {
@@ -224,6 +228,13 @@ func (s *streamSegment) WriteTo(w io.Writer) (n int64, err error) {
 func (b *SegmentWriter) Reset() {
 	b.streams.Clear()
 	b.buf1.Reset()
+	b.inputSize = 0
+}
+
+// InputSize returns the total size of the input data written to the writer.
+// It doesn't account for timestamps and labels.
+func (b *SegmentWriter) InputSize() int64 {
+	return b.inputSize
 }
 
 type SegmentReader struct {
@@ -332,3 +343,23 @@ func (r *SegmentReader) Series(ctx context.Context) (*SeriesIter, error) {
 
 	return NewSeriesIter(r.idr, ps, r.b), nil
 }
+
+type Sizes struct {
+	Index  int64
+	Series []int64
+}
+
+func (r *SegmentReader) Sizes() (Sizes, error) {
+	var sizes Sizes
+	sizes.Index = int64(r.idr.Size())
+	it, err := r.Series(context.Background())
+	if err != nil {
+		return sizes, err
+	}
+	sizes.Series = []int64{}
+	for it.Next() {
+		_, size := it.chunksMeta[0].Ref.Unpack()
+		sizes.Series = append(sizes.Series, int64(size))
+	}
+	return sizes, err
+}

pkg/storage/wal/segment_test.go

@@ -8,12 +8,14 @@ import (
 	"testing"
 	"time"
 
+	"github.com/dustin/go-humanize"
 	"github.com/prometheus/prometheus/model/labels"
 	"github.com/stretchr/testify/require"
 
 	"github.com/grafana/loki/v3/pkg/logproto"
 	"github.com/grafana/loki/v3/pkg/logql/syntax"
 	"github.com/grafana/loki/v3/pkg/storage/stores/shipper/indexshipper/tsdb"
+	"github.com/grafana/loki/v3/pkg/storage/wal/testdata"
 
 	"github.com/grafana/loki/pkg/push"
 )
@@ -186,3 +188,68 @@ func TestMultiTenantWrite(t *testing.T) {
 	require.NoError(t, iter.Err())
 	require.ElementsMatch(t, expectedSeries, actualSeries)
 }
+
+func TestCompression(t *testing.T) {
+	size := []int64{250 * 1024, 500 * 1024, 750 * 1024, 1 << 20, 2 << 20, 5 << 20, 10 << 20, 20 << 20, 50 << 20, 100 << 20}
+	for _, s := range size {
+		t.Run(fmt.Sprintf("size %.2f", float64(s)/(1024*1024)), func(t *testing.T) {
+			testCompression(t, s)
+		})
+	}
+}
+
+func testCompression(t *testing.T, maxInputSize int64) {
+	w := NewWalSegmentWriter()
+	dst := bytes.NewBuffer(nil)
+	files := testdata.Files()
+	lbls := []labels.Labels{}
+	generators := []*testdata.LogGenerator{}
+
+	for _, file := range files {
+		lbls = append(lbls, labels.FromStrings("filename", file, "namespace", "dev"))
+		lbls = append(lbls, labels.FromStrings("filename", file, "namespace", "prod"))
+		g := testdata.NewLogGenerator(t, file)
+		generators = append(generators, g, g)
+	}
+	inputSize := int64(0)
+	for inputSize < maxInputSize {
+		for i, lbl := range lbls {
+			more, line := generators[i].Next()
+			if !more {
+				continue
+			}
+			inputSize += int64(len(line))
+			w.Append("tenant", lbl.String(), lbl, []*push.Entry{
+				{Timestamp: time.Unix(0, int64(i*1e9)), Line: string(line)},
+			})
+		}
+	}
+
+	require.Equal(t, inputSize, w.InputSize())
+
+	now := time.Now()
+	n, err := w.WriteTo(dst)
+	require.NoError(t, err)
+	require.True(t, n > 0)
+	compressionTime := time.Since(now)
+
+	r, err := NewReader(dst.Bytes())
+	require.NoError(t, err)
+	inputSizeMB := float64(w.InputSize()) / (1024 * 1024)
+	outputSizeMB := float64(dst.Len()) / (1024 * 1024)
+	compressionRatio := (1 - (outputSizeMB / inputSizeMB)) * 100
+
+	t.Logf("Input Size: %s\n", humanize.Bytes(uint64(w.InputSize())))
+	t.Logf("Output Size: %s\n", humanize.Bytes(uint64(dst.Len())))
+	t.Logf("Compression Ratio: %.2f%%\n", compressionRatio)
+	t.Logf("Write time: %s\n", compressionTime)
+	sizes, err := r.Sizes()
+	require.NoError(t, err)
+	t.Logf("Total chunks %d\n", len(sizes.Series))
+	t.Logf("Index size  %s\n", humanize.Bytes(uint64(sizes.Index)))
+	sizesString := ""
+	for _, size := range sizes.Series {
+		sizesString += humanize.Bytes(uint64(size)) + ", "
+	}
+	t.Logf("Series sizes: [%s]\n", sizesString)
+}

pkg/storage/wal/testdata/generator.go

@@ -0,0 +1,71 @@
+package testdata
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type LogGenerator struct {
+	f *os.File
+	s *bufio.Scanner
+}
+
+func (g *LogGenerator) Next() (bool, []byte) {
+	if g.s.Scan() {
+		return true, g.s.Bytes()
+	}
+	g.reset()
+	return g.s.Scan(), g.s.Bytes()
+}
+
+func (g *LogGenerator) Close() {
+	if g.f != nil {
+		g.f.Close()
+	}
+	g.f = nil
+}
+
+func (g *LogGenerator) reset() {
+	_, _ = g.f.Seek(0, 0)
+	g.s = bufio.NewScanner(g.f)
+}
+
+func NewLogGenerator(t testing.TB, filename string) *LogGenerator {
+	t.Helper()
+	file, err := os.Open(filename)
+	require.NoError(t, err)
+
+	return &LogGenerator{
+		f: file,
+		s: bufio.NewScanner(file),
+	}
+}
+
+func Files() []string {
+	testdataDir := "./testdata"
+	files, err := os.ReadDir(testdataDir)
+	if err != nil && !os.IsNotExist(err) {
+		if !os.IsNotExist(err) {
+			panic(err)
+		}
+		testdataDir = "../testdata"
+		files, err = os.ReadDir(testdataDir)
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	var fileNames []string
+	for _, file := range files {
+		if !file.IsDir() {
+			filePath := filepath.Join(testdataDir, file.Name())
+			fileNames = append(fileNames, filePath)
+		}
+	}
+
+	return fileNames
+}