From d950b6546c1fba17c5ee980e4235f3d424b7ac98 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Sun, 11 Dec 2022 21:33:51 +0500
Subject: [PATCH 1/5] Add notes about current store state

---
 README.md | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 5ed2b58..4474fec 100644
--- a/README.md
+++ b/README.md
@@ -4,17 +4,17 @@ Simple key-value store for single-user applications.
 
 ## Pros
 
-* Simple one file structure
+* Simple two file structure (data file and index file)
 * Internal Zstandard compression by [klauspost/compress/zstd](https://github.com/klauspost/compress/tree/master/zstd)
 * Threadsafe operations through `sync.RWMutex`
 
 ## Cons
 
 * Index stored in memory (`map[key hash (28 bytes)]file offset (int64)`)
-* Need to read the whole file on store open to create file index (you can use index file options to avoid this)
+* No transaction system
+* Index file is fully rewrited on every store commit
 * No way to recover disk space from deleted records
 * Write/Delete operations block Read and each other operations
-* Need to decode whole file until stored value
 
 ## Usage
 
@@ -63,9 +63,6 @@ type Options struct {
 
 	// Disk write buffer size in bytes
 	DiskBufferSize int
-
-	// Use index file
-	UseIndexFile bool
 }
 
 ```
@@ -87,6 +84,17 @@ File is log stuctured list of commands:
 | Length | Record body bytes length | int64    |
 | Body   | Gob-encoded record       | variable |
 
+Index file is simple gob-encoded map:
+
+```go
+map[string]struct {
+	BlockOffset  int64
+	RecordOffset int64
+}
+```
+
+where map key is data key hash and value - data offset in data file.
+
 ## Resource consumption
 
 Store requirements:
@@ -97,4 +105,4 @@ Store requirements:
 ## TODO
 
 - [ ] Add recovery previous state of store file on write error
-- [ ] Add fast file seek to value (add compressed block start position)
+- [ ] Add method for index rebuild

From 2791b39d486aff9cdf93c83244fe01e19e8696e8 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Mon, 12 Dec 2022 21:01:00 +0500
Subject: [PATCH 2/5] Delete test files

---
 TestBufferRead.zkv.idx  | Bin 131 -> 0 bytes
 TestSmallWrites.zkv.idx | Bin 3465 -> 0 bytes
 2 files changed, 0 insertions(+), 0 deletions(-)
 delete mode 100644 TestBufferRead.zkv.idx
 delete mode 100644 TestSmallWrites.zkv.idx

diff --git a/TestBufferRead.zkv.idx b/TestBufferRead.zkv.idx
deleted file mode 100644
index ced4e784f1da329060e7333b77539b4bdd131895..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 131
zcmd=8-_F9w^uL3Fk%#er8v}#x|5j#3rvGgWj7*H&PC5C>+5Ty1#i=EXEDVf1L8;04
zMJaFr1_qb^9Slq|6TYa57L>+(+4J+><R83z7151T^HzJmFrS{`Xv-ke(sEFdsr!2F
eg|$+lA~73T%r*5ZB(^>Y^Xrv#WBkYHzyJUezb&5t

diff --git a/TestSmallWrites.zkv.idx b/TestSmallWrites.zkv.idx
deleted file mode 100644
index 15a6d389fca5b0bafaacc87682cfb2e099a9f8ad..0000000000000000000000000000000000000000
GIT binary patch
literal 0
HcmV?d00001

literal 3465
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zMJaFr28MsU9{)QSQe^V#`j-nt@beyD^5?)k^EZoISG`s^z~|w(VEWV|#(x=47-W>L
zTKuZdbq{~?aBhJ{SVMNP>}|nK$4uvb$+S7m_^+UeLB^lse|ONP^bIG|?>_y`knwM=
z81E~Y2vupV*v~5&|CKf{$n<)+Mf}vA7bc*!beG-g3(q?*s9OG+@$669AtMpSe*zf{
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zJl@ct9#H@JQPzg4%nshYIgI~u)-lKwm*-x5*?y}2s@12UkNUsmWJRWEi94-#JnU{f
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z_v6;n!n40xR3G+6NnUn}mG9<d{Kw|UAhY$3dZV7siFsEY9fMv+u%}&<o$7Kdl4skc
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zqm!4pT64UPTeIXe@n@WIzV>eWzr$L-jQ{j|7-VK2EG(8uT-|RHJ!`^|_DZ9UYO75T
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From 822504e8a01b5e62cf72733ffb488b514a78c106 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Wed, 5 Apr 2023 21:17:38 +0500
Subject: [PATCH 3/5] Update deps

---
 go.mod | 4 ++--
 go.sum | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/go.mod b/go.mod
index 392f6ec..4dc95a4 100644
--- a/go.mod
+++ b/go.mod
@@ -3,8 +3,8 @@ module github.com/nxshock/zkv
 go 1.19
 
 require (
-	github.com/klauspost/compress v1.15.12
-	github.com/stretchr/testify v1.8.1
+	github.com/klauspost/compress v1.16.4
+	github.com/stretchr/testify v1.8.2
 )
 
 require (
diff --git a/go.sum b/go.sum
index 8609118..abc35b1 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,8 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/klauspost/compress v1.15.12 h1:YClS/PImqYbn+UILDnqxQCZ3RehC9N318SU3kElDUEM=
-github.com/klauspost/compress v1.15.12/go.mod h1:QPwzmACJjUTFsnSHH934V6woptycfrDDJnH7hvFVbGM=
+github.com/klauspost/compress v1.16.4 h1:91KN02FnsOYhuunwU4ssRe8lc2JosWmizWa91B5v1PU=
+github.com/klauspost/compress v1.16.4/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -10,8 +10,8 @@ github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSS
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

From 832d12c43bcbd80b0ec8975318eb67d4e36105c1 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Sat, 15 Apr 2023 22:33:37 +0500
Subject: [PATCH 4/5] Move record tests to separate file

---
 record_test.go | 35 +++++++++++++++++++++++++++++++++++
 zkv_test.go    | 28 ----------------------------
 2 files changed, 35 insertions(+), 28 deletions(-)
 create mode 100644 record_test.go

diff --git a/record_test.go b/record_test.go
new file mode 100644
index 0000000..1e69354
--- /dev/null
+++ b/record_test.go
@@ -0,0 +1,35 @@
+package zkv
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRecord(t *testing.T) {
+	buf := new(bytes.Buffer)
+
+	var records []Record
+
+	for i := 0; i < 10; i++ {
+		record, err := newRecord(RecordTypeSet, i, i)
+		assert.NoError(t, err)
+
+		records = append(records, *record)
+
+		b, err := record.Marshal()
+		assert.NoError(t, err)
+
+		_, err = buf.Write(b)
+		assert.NoError(t, err)
+	}
+
+	for i := 0; i < 10; i++ {
+		_, record, err := readRecord(buf)
+		assert.NoError(t, err)
+
+		assert.Equal(t, record.KeyHash, records[i].KeyHash)
+		assert.Equal(t, record.ValueBytes, records[i].ValueBytes)
+	}
+}
diff --git a/zkv_test.go b/zkv_test.go
index 4ec0d41..5229178 100644
--- a/zkv_test.go
+++ b/zkv_test.go
@@ -1,40 +1,12 @@
 package zkv
 
 import (
-	"bytes"
 	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func TestRecord(t *testing.T) {
-	buf := new(bytes.Buffer)
-
-	var records []Record
-
-	for i := 0; i < 10; i++ {
-		record, err := newRecord(RecordTypeSet, i, i)
-		assert.NoError(t, err)
-
-		records = append(records, *record)
-
-		b, err := record.Marshal()
-		assert.NoError(t, err)
-
-		_, err = buf.Write(b)
-		assert.NoError(t, err)
-	}
-
-	for i := 0; i < 10; i++ {
-		_, record, err := readRecord(buf)
-		assert.NoError(t, err)
-
-		assert.Equal(t, record.KeyHash, records[i].KeyHash)
-		assert.Equal(t, record.ValueBytes, records[i].ValueBytes)
-	}
-}
-
 func TestReadWriteBasic(t *testing.T) {
 	const filePath = "TestReadWriteBasic.zkv"
 	const recordCount = 100

From 583f60da9f9ffd00701a3ebbbbad8ef17f232a90 Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Sun, 16 Apr 2023 10:32:58 +0500
Subject: [PATCH 5/5] Add RebuildIndex() func

---
 TestDeleteBasic.zkv.idx    | Bin 0 -> 3431 bytes
 TestSmallWrites.zkv.idx    | Bin 0 -> 3465 bytes
 testdata/TestReadBlock.zkv | Bin 0 -> 644 bytes
 utils.go                   |  12 +++
 zkv.go                     | 188 ++++++++++++++++++++++++++++---------
 zkv_test.go                |  55 +++++++++++
 6 files changed, 209 insertions(+), 46 deletions(-)
 create mode 100644 TestDeleteBasic.zkv.idx
 create mode 100644 TestSmallWrites.zkv.idx
 create mode 100644 testdata/TestReadBlock.zkv

diff --git a/TestDeleteBasic.zkv.idx b/TestDeleteBasic.zkv.idx
new file mode 100644
index 0000000000000000000000000000000000000000..b341db72544cb67bd4fd560f43e99a37bd67a577
GIT binary patch
literal 3431
zcmd=8-_F9w^uL3Fk%#er8v}#x|5j#3rvGgWj7*H&PC5C>+5Ty1#i=EXEDVf1L8;04
zMJaFr28MsUYX3VJl4Z6&+{_#CL)f|9W_`!go0pxu+Sl%mF*w?v`B(ov(?8xX3^KD^
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diff --git a/TestSmallWrites.zkv.idx b/TestSmallWrites.zkv.idx
new file mode 100644
index 0000000000000000000000000000000000000000..6de70daa2dcb36824aeffb528ea00ae58a9cd592
GIT binary patch
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diff --git a/testdata/TestReadBlock.zkv b/testdata/TestReadBlock.zkv
new file mode 100644
index 0000000000000000000000000000000000000000..7916c5b25ea46be9f90ae34ec57b2de949cc318b
GIT binary patch
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zSCbVX?(1Y>=!7_rffnvFfx55df6M=aicJ5z|6kAjf8qaHsZf!a{~KA%HT5eb{%`&N
zB+T!BucRB;bu0`#*843XuA@)rsaD##`TbwRrv889|Hc1T{eS%bo_S$%(f>}~|E-q)
zxBlPxzw7_Jg#T;B!R}*Y2;#6)gShV`3&TVjhMo;H^!BU%fB*l)|5ly<`~PqKzxMyH
s|LbM`KQH|M%k2MD>Hib|uQvOCw#xYb_y2GHzx#g>>`D%XrF==j0L|{;qyPW_

literal 0
HcmV?d00001

diff --git a/utils.go b/utils.go
index 97d63be..ae570b2 100644
--- a/utils.go
+++ b/utils.go
@@ -4,7 +4,9 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"encoding/gob"
+	"errors"
 	"io"
+	"os"
 )
 
 func encode(value interface{}) ([]byte, error) {
@@ -40,3 +42,13 @@ func skip(r io.Reader, count int64) (err error) {
 
 	return err
 }
+
+func isFileExists(filePath string) (bool, error) {
+	if _, err := os.Stat(filePath); err == nil {
+		return true, nil
+	} else if errors.Is(err, os.ErrNotExist) {
+		return false, nil
+	} else {
+		return false, err
+	}
+}
diff --git a/zkv.go b/zkv.go
index 1c4d543..8a2b7d6 100644
--- a/zkv.go
+++ b/zkv.go
@@ -37,7 +37,7 @@ type Store struct {
 func OpenWithOptions(filePath string, options Options) (*Store, error) {
 	options.setDefaults()
 
-	database := &Store{
+	store := &Store{
 		dataOffset:       make(map[string]Offsets),
 		bufferDataOffset: make(map[string]int64),
 		buffer:           new(bytes.Buffer),
@@ -48,50 +48,30 @@ func OpenWithOptions(filePath string, options Options) (*Store, error) {
 	if options.useIndexFile {
 		idxFile, err := os.Open(filePath + indexFileExt)
 		if err == nil {
-			err = gob.NewDecoder(idxFile).Decode(&database.dataOffset)
-			if err == nil {
-				return database, nil
+			err = gob.NewDecoder(idxFile).Decode(&store.dataOffset)
+			if err != nil {
+				return nil, err
 			}
+
+			return store, nil
 		}
 	}
 
-	// restore file data
-	readF, err := os.Open(filePath)
-	if os.IsNotExist(err) {
-		// Empty datebase
-		return database, nil
-	} else if err != nil {
-		return nil, fmt.Errorf("open file for indexing: %v", err)
-	}
-	defer readF.Close()
-
-	decompressor, err := zstd.NewReader(readF)
+	exists, err := isFileExists(filePath)
 	if err != nil {
-		return nil, fmt.Errorf("decompressor initialization: %v", err)
-	}
-	defer decompressor.Close()
-
-	offset := int64(0)
-	for {
-		n, record, err := readRecord(decompressor)
-		if err == io.EOF {
-			break
-		}
-		if err != nil {
-			return nil, fmt.Errorf("read record error: %v", err)
-		}
-
-		switch record.Type {
-		case RecordTypeSet:
-			database.dataOffset[string(record.KeyHash[:])] = Offsets{} // offset
-		case RecordTypeDelete:
-			delete(database.dataOffset, string(record.KeyHash[:]))
-		}
-
-		offset += n
+		return nil, err
 	}
 
-	return database, nil
+	if !exists {
+		return store, nil
+	}
+
+	err = store.rebuildIndex()
+	if err != nil {
+		return nil, err
+	}
+
+	return store, nil
 }
 
 func Open(filePath string) (*Store, error) {
@@ -395,14 +375,7 @@ func (s *Store) flush() error {
 
 	// Update index file only on data update
 	if s.options.useIndexFile && l > 0 {
-		idxBuf := new(bytes.Buffer)
-
-		err = gob.NewEncoder(idxBuf).Encode(s.dataOffset)
-		if err != nil {
-			return err
-		}
-
-		err = os.WriteFile(s.filePath+indexFileExt, idxBuf.Bytes(), 0644)
+		err = s.saveIndex()
 		if err != nil {
 			return err
 		}
@@ -410,3 +383,126 @@ func (s *Store) flush() error {
 
 	return nil
 }
+
+func readBlock(r *bufio.Reader) (line []byte, n int, err error) {
+	delim := []byte{0x28, 0xb5, 0x2f, 0xfd}
+
+	line = make([]byte, len(delim))
+	copy(line, delim)
+
+	for {
+		s, err := r.ReadBytes(delim[len(delim)-1])
+		line = append(line, []byte(s)...)
+		if err != nil {
+			if bytes.Equal(line, delim) { // contains only magic number
+				return []byte{}, 0, err
+			} else {
+				return line, len(s), err
+			}
+		}
+
+		if bytes.Equal(line, append(delim, delim...)) { // first block
+			line = make([]byte, len(delim))
+			copy(line, delim)
+			continue
+		}
+
+		if bytes.HasSuffix(line, delim) {
+			return line[:len(line)-len(delim)], len(s), nil
+		}
+	}
+}
+
+// RebuildIndex renews index from store file
+func (s *Store) RebuildIndex() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	err := s.rebuildIndex()
+	if err != nil {
+		return err
+	}
+
+	if s.options.useIndexFile {
+		return s.saveIndex()
+	}
+
+	return nil
+}
+
+func (s *Store) rebuildIndex() error {
+	f, err := os.Open(s.filePath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	r := bufio.NewReader(f)
+
+	var blockOffset int64
+
+	s.dataOffset = make(map[string]Offsets)
+
+	for {
+		l, n, err := readBlock(r)
+		if err != nil {
+			if err != io.EOF {
+				return err
+			} else if err == io.EOF && len(l) == 0 {
+				break
+			}
+		}
+
+		dec, err := zstd.NewReader(bytes.NewReader(l))
+
+		var recordOffset int64
+		for {
+			n, record, err := readRecord(dec)
+			if err != nil {
+				if err == io.EOF {
+					break
+				} else {
+					return err
+				}
+			}
+
+			switch record.Type {
+			case RecordTypeSet:
+				s.dataOffset[string(record.KeyHash[:])] = Offsets{BlockOffset: blockOffset, RecordOffset: recordOffset}
+			case RecordTypeDelete:
+				delete(s.dataOffset, string(record.KeyHash[:]))
+			}
+			recordOffset += n
+		}
+
+		blockOffset += int64(n)
+	}
+
+	idxBuf := new(bytes.Buffer)
+
+	err = gob.NewEncoder(idxBuf).Encode(s.dataOffset)
+	if err != nil {
+		return err
+	}
+
+	err = os.WriteFile(s.filePath+indexFileExt, idxBuf.Bytes(), 0644)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (s *Store) saveIndex() error {
+	f, err := os.OpenFile(s.filePath+indexFileExt, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+
+	err = gob.NewEncoder(f).Encode(s.dataOffset)
+	if err != nil {
+		return err
+	}
+
+	return f.Close()
+}
diff --git a/zkv_test.go b/zkv_test.go
index 5229178..ec2d2de 100644
--- a/zkv_test.go
+++ b/zkv_test.go
@@ -1,6 +1,8 @@
 package zkv
 
 import (
+	"bufio"
+	"io"
 	"os"
 	"testing"
 
@@ -355,3 +357,56 @@ func TestIndexFileBasic(t *testing.T) {
 	err = db.Close()
 	assert.NoError(t, err)
 }
+
+func TestReadBlock(t *testing.T) {
+	file, err := os.Open("testdata/TestReadBlock.zkv")
+	assert.NoError(t, err)
+	defer file.Close()
+
+	r := bufio.NewReader(file)
+
+	line, _, err := readBlock(r)
+	assert.Equal(t, []byte{0x28, 0xb5, 0x2f, 0xfd, 0x04, 0x00, 0x99, 0x04, 0x00, 0x8b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x39, 0xff, 0x81, 0x03, 0x01, 0x01, 0x06, 0x52, 0x65, 0x63, 0x6f, 0x72, 0x64, 0x01, 0xff, 0x82, 0x00, 0x01, 0x03, 0x01, 0x04, 0x54, 0x79, 0x70, 0x65, 0x01, 0x06, 0x00, 0x01, 0x07, 0x4b, 0x65, 0x79, 0x48, 0x61, 0x73, 0x68, 0x01, 0xff, 0x84, 0x00, 0x01, 0x0a, 0x56, 0x61, 0x6c, 0x75, 0x65, 0x42, 0x79, 0x74, 0x65, 0x73, 0x01, 0x0a, 0x00, 0x00, 0x00, 0x19, 0xff, 0x83, 0x01, 0x01, 0x01, 0x09, 0x5b, 0x32, 0x38, 0x5d, 0x75, 0x69, 0x6e, 0x74, 0x38, 0x01, 0xff, 0x84, 0x00, 0x01, 0x06, 0x01, 0x38, 0x00, 0x00, 0x36, 0xff, 0x82, 0x01, 0x01, 0x01, 0x1c, 0xff, 0x90, 0xff, 0xf4, 0x25, 0x15, 0x70, 0x75, 0x5c, 0xff, 0xf4, 0xff, 0xbc, 0xff, 0xf9, 0xff, 0xde, 0xff, 0x93, 0xff, 0xf8, 0x0d, 0x0e, 0x78, 0x5b, 0xff, 0x81, 0xff, 0x95, 0x6e, 0xff, 0xab, 0x4b, 0xff, 0xe8, 0x37, 0xff, 0x97, 0x68, 0x41, 0x3d, 0x01, 0x04, 0x03, 0x04, 0x00, 0x02, 0x00, 0x25, 0xd5, 0x63, 0x21}, line)
+	line, _, err = readBlock(r)
+	assert.Equal(t, []byte{0x28, 0xb5, 0x2f, 0xfd, 0x04, 0x00, 0x89, 0x04, 0x00, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x39, 0xff, 0x81, 0x03, 0x01, 0x01, 0x06, 0x52, 0x65, 0x63, 0x6f, 0x72, 0x64, 0x01, 0xff, 0x82, 0x00, 0x01, 0x03, 0x01, 0x04, 0x54, 0x79, 0x70, 0x65, 0x01, 0x06, 0x00, 0x01, 0x07, 0x4b, 0x65, 0x79, 0x48, 0x61, 0x73, 0x68, 0x01, 0xff, 0x84, 0x00, 0x01, 0x0a, 0x56, 0x61, 0x6c, 0x75, 0x65, 0x42, 0x79, 0x74, 0x65, 0x73, 0x01, 0x0a, 0x00, 0x00, 0x00, 0x19, 0xff, 0x83, 0x01, 0x01, 0x01, 0x09, 0x5b, 0x32, 0x38, 0x5d, 0x75, 0x69, 0x6e, 0x74, 0x38, 0x01, 0xff, 0x84, 0x00, 0x01, 0x06, 0x01, 0x38, 0x00, 0x00, 0x34, 0xff, 0x82, 0x01, 0x01, 0x01, 0x1c, 0xff, 0x84, 0xff, 0x84, 0xff, 0xc1, 0x21, 0x02, 0xff, 0x8b, 0xff, 0xd7, 0x6d, 0xff, 0xd0, 0xff, 0xad, 0x1a, 0x55, 0x14, 0x5c, 0xff, 0xb1, 0x04, 0x37, 0x29, 0x2f, 0x78, 0x18, 0xff, 0xb5, 0xff, 0xe4, 0x56, 0x4e, 0xff, 0x8d, 0x19, 0x46, 0x01, 0x04, 0x03, 0x04, 0x00, 0x04, 0x00, 0x0c, 0x3b, 0xbf, 0x39}, line)
+	line, _, err = readBlock(r)
+	assert.Equal(t, []byte{0x28, 0xb5, 0x2f, 0xfd, 0x04, 0x00, 0x99, 0x04, 0x00, 0x8b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x39, 0xff, 0x81, 0x03, 0x01, 0x01, 0x06, 0x52, 0x65, 0x63, 0x6f, 0x72, 0x64, 0x01, 0xff, 0x82, 0x00, 0x01, 0x03, 0x01, 0x04, 0x54, 0x79, 0x70, 0x65, 0x01, 0x06, 0x00, 0x01, 0x07, 0x4b, 0x65, 0x79, 0x48, 0x61, 0x73, 0x68, 0x01, 0xff, 0x84, 0x00, 0x01, 0x0a, 0x56, 0x61, 0x6c, 0x75, 0x65, 0x42, 0x79, 0x74, 0x65, 0x73, 0x01, 0x0a, 0x00, 0x00, 0x00, 0x19, 0xff, 0x83, 0x01, 0x01, 0x01, 0x09, 0x5b, 0x32, 0x38, 0x5d, 0x75, 0x69, 0x6e, 0x74, 0x38, 0x01, 0xff, 0x84, 0x00, 0x01, 0x06, 0x01, 0x38, 0x00, 0x00, 0x36, 0xff, 0x82, 0x01, 0x01, 0x01, 0x1c, 0x25, 0x79, 0x3e, 0x46, 0x4e, 0xff, 0xac, 0x06, 0x27, 0xff, 0xb1, 0xff, 0xa3, 0xff, 0xaa, 0xff, 0xe3, 0xff, 0xde, 0x37, 0x71, 0x63, 0x72, 0xff, 0x89, 0x0d, 0xff, 0x85, 0x39, 0xff, 0xb5, 0xff, 0xb9, 0xff, 0x8a, 0xff, 0x9e, 0x60, 0xff, 0xad, 0x17, 0x01, 0x04, 0x03, 0x04, 0x00, 0x06, 0x00, 0x52, 0x08, 0x3e, 0x26}, line)
+	line, _, err = readBlock(r)
+	assert.Equal(t, []byte{0x28, 0xb5, 0x2f, 0xfd, 0x04, 0x00, 0xc9, 0x04, 0x00, 0x91, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x39, 0xff, 0x81, 0x03, 0x01, 0x01, 0x06, 0x52, 0x65, 0x63, 0x6f, 0x72, 0x64, 0x01, 0xff, 0x82, 0x00, 0x01, 0x03, 0x01, 0x04, 0x54, 0x79, 0x70, 0x65, 0x01, 0x06, 0x00, 0x01, 0x07, 0x4b, 0x65, 0x79, 0x48, 0x61, 0x73, 0x68, 0x01, 0xff, 0x84, 0x00, 0x01, 0x0a, 0x56, 0x61, 0x6c, 0x75, 0x65, 0x42, 0x79, 0x74, 0x65, 0x73, 0x01, 0x0a, 0x00, 0x00, 0x00, 0x19, 0xff, 0x83, 0x01, 0x01, 0x01, 0x09, 0x5b, 0x32, 0x38, 0x5d, 0x75, 0x69, 0x6e, 0x74, 0x38, 0x01, 0xff, 0x84, 0x00, 0x01, 0x06, 0x01, 0x38, 0x00, 0x00, 0x3c, 0xff, 0x82, 0x01, 0x01, 0x01, 0x1c, 0xff, 0xbf, 0x25, 0xff, 0xef, 0xff, 0xc8, 0xff, 0x85, 0x2c, 0xff, 0xbf, 0xff, 0xb5, 0xff, 0xad, 0xff, 0xfa, 0xff, 0xaf, 0x1c, 0xff, 0xe7, 0x71, 0xff, 0xfa, 0x36, 0xff, 0x95, 0x1b, 0xff, 0x91, 0xff, 0xab, 0x36, 0xff, 0xcd, 0x7a, 0x33, 0xff, 0xf7, 0xff, 0xec, 0xff, 0xee, 0xff, 0xc1, 0x01, 0x04, 0x03, 0x04, 0x00, 0x08, 0x00, 0xa5, 0x0e, 0x62, 0x53}, line)
+
+	line, _, err = readBlock(r)
+	assert.Equal(t, line, []byte{})
+	assert.Equal(t, io.EOF, err)
+}
+
+func TestRebuildIndex(t *testing.T) {
+	const filePath = "TestRebuiltIndex.zkv"
+	const recordCount = 4
+	defer os.Remove(filePath)
+	defer os.Remove(filePath + indexFileExt)
+
+	for i := 1; i <= recordCount; i++ {
+		db, err := Open(filePath)
+		assert.NoError(t, err)
+
+		err = db.Set(i, i)
+		assert.NoError(t, err)
+
+		err = db.Close()
+		assert.NoError(t, err)
+	}
+
+	db, err := Open(filePath)
+	assert.NoError(t, err)
+
+	err = db.RebuildIndex()
+	assert.NoError(t, err)
+
+	for i := 1; i <= recordCount; i++ {
+		var gotValue int
+
+		err = db.Get(i, &gotValue)
+		assert.NoError(t, err)
+		assert.Equal(t, i, gotValue)
+	}
+}