From 6cee197767a5337cf00ead4756764f2d0a18c3fd Mon Sep 17 00:00:00 2001
From: Alex Sharov <AskAlexSharov@gmail.com>
Date: Wed, 4 Dec 2024 09:13:52 +0700
Subject: [PATCH] recsplit: compact Enum=true representation (#12970)

used wrong `bytesPerRec`
It reducing hot random-read parts of `.efi` and some `.idx` ~25%

For: https://github.com/erigontech/erigon/issues/12852

PR is backward/forward compatible
---
 erigon-lib/recsplit/index.go         | 1 +
 erigon-lib/recsplit/recsplit.go      | 6 +++++-
 erigon-lib/recsplit/recsplit_test.go | 7 ++++---
 turbo/app/snapshots_cmd.go           | 2 +-
 4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/erigon-lib/recsplit/index.go b/erigon-lib/recsplit/index.go
index 5dc9534de77..ae52667a84d 100644
--- a/erigon-lib/recsplit/index.go
+++ b/erigon-lib/recsplit/index.go
@@ -353,6 +353,7 @@ func (idx *Index) Lookup(bucketHash, fingerprint uint64) (uint64, bool) {
 	}
 	b := gr.ReadNext(idx.golombParam(m))
 	rec := int(cumKeys) + int(remap16(remix(fingerprint+idx.startSeed[level]+b), m))
+
 	pos := 1 + 8 + idx.bytesPerRec*(rec+1)
 
 	found := binary.BigEndian.Uint64(idx.data[pos:]) & idx.recMask
diff --git a/erigon-lib/recsplit/recsplit.go b/erigon-lib/recsplit/recsplit.go
index 161cd2343f1..76e06d30cd0 100644
--- a/erigon-lib/recsplit/recsplit.go
+++ b/erigon-lib/recsplit/recsplit.go
@@ -604,7 +604,11 @@ func (rs *RecSplit) Build(ctx context.Context) error {
 		return fmt.Errorf("write number of keys: %w", err)
 	}
 	// Write number of bytes per index record
-	rs.bytesPerRec = common.BitLenToByteLen(bits.Len64(rs.maxOffset))
+	if rs.enums {
+		rs.bytesPerRec = common.BitLenToByteLen(bits.Len64(rs.keysAdded + 1))
+	} else {
+		rs.bytesPerRec = common.BitLenToByteLen(bits.Len64(rs.maxOffset))
+	}
 	if err = rs.indexW.WriteByte(byte(rs.bytesPerRec)); err != nil {
 		return fmt.Errorf("write bytes per record: %w", err)
 	}
diff --git a/erigon-lib/recsplit/recsplit_test.go b/erigon-lib/recsplit/recsplit_test.go
index 5d7062d18ae..6c770a876fe 100644
--- a/erigon-lib/recsplit/recsplit_test.go
+++ b/erigon-lib/recsplit/recsplit_test.go
@@ -149,8 +149,9 @@ func TestTwoLayerIndex(t *testing.T) {
 	tmpDir := t.TempDir()
 	indexFile := filepath.Join(tmpDir, "index")
 	salt := uint32(1)
+	N := 2571
 	rs, err := NewRecSplit(RecSplitArgs{
-		KeyCount:           100,
+		KeyCount:           N,
 		BucketSize:         10,
 		Salt:               &salt,
 		TmpDir:             tmpDir,
@@ -162,7 +163,7 @@ func TestTwoLayerIndex(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	for i := 0; i < 100; i++ {
+	for i := 0; i < N; i++ {
 		if err = rs.AddKey([]byte(fmt.Sprintf("key %d", i)), uint64(i*17)); err != nil {
 			t.Fatal(err)
 		}
@@ -173,7 +174,7 @@ func TestTwoLayerIndex(t *testing.T) {
 
 	idx := MustOpen(indexFile)
 	defer idx.Close()
-	for i := 0; i < 100; i++ {
+	for i := 0; i < N; i++ {
 		reader := NewIndexReader(idx)
 		e, _ := reader.Lookup([]byte(fmt.Sprintf("key %d", i)))
 		if e != uint64(i) {
diff --git a/turbo/app/snapshots_cmd.go b/turbo/app/snapshots_cmd.go
index 7208f9fd4a1..67e005b4659 100644
--- a/turbo/app/snapshots_cmd.go
+++ b/turbo/app/snapshots_cmd.go
@@ -88,7 +88,7 @@ func joinFlags(lists ...[]cli.Flag) (res []cli.Flag) {
 
 var snapshotCommand = cli.Command{
 	Name:    "seg",
-	Aliases: []string{"snapshots"},
+	Aliases: []string{"snapshots", "segments"},
 	Usage:   `Managing historical data segments (partitions)`,
 	Before: func(cliCtx *cli.Context) error {
 		go mem.LogMemStats(cliCtx.Context, log.New())