Update CHANGELOG for 1.0.0

Co-authored-by: James Mills <1290234+prologic@users.noreply.github.com>
Co-authored-by: James Mills <prologic@shortcircuit.net.au>
Co-authored-by: Tai Groot <tai@taigrr.com>
Reviewed-on: https://git.mills.io/prologic/bitcask/pulls/160
Co-authored-by: James Mills <james@mills.io>
Co-committed-by: James Mills <james@mills.io>

.drone.yml

@@ -5,12 +5,6 @@ name: default
 steps:
   - name: build & run tests
     image: r.mills.io/prologic/golang-alpine
-    volumes:
-      - name: gomodcache
-        path: /go/pkg/mod/cache
-    privileged: true
-    environment:
-      GOPROXY: https://goproxy.mills.io
     commands:
       - make build
       - make test
@@ -25,7 +19,10 @@ steps:
         - success
         - failure
 
-volumes:
-  - name: gomodcache
-    host:
-      path: /var/lib/cache/go
+trigger:
+  branch:
+    - master
+  event:
+    - tag
+    - push
+    - pull_request

CHANGELOG.md

@@ -1,4 +1,32 @@
 
+<a name="1.0.0"></a>
+## [1.0.0](https://git.mills.io/prologic/bitcask/compare/v0.3.14...1.0.0) (2021-07-22)
+
+### Updates
+
+* Update README
+
+
+<a name="v0.3.14"></a>
+## [v0.3.14](https://git.mills.io/prologic/bitcask/compare/v0.3.13...v0.3.14) (2021-07-21)
+
+### Bug Fixes
+
+* Fix runGC behaviour to correctly delete all expired keys (#229)
+* Fix missing push event
+* Fix how CI is triggered
+* Fix README Go Reference badge
+* Fix README badges
+
+### Features
+
+* Add RangeScan() support (#160)
+
+### Updates
+
+* Update CHANGELOG for v0.3.14
+
+
 <a name="v0.3.13"></a>
 ## [v0.3.13](https://git.mills.io/prologic/bitcask/compare/v0.3.12...v0.3.13) (2021-07-16)
 
@@ -10,6 +38,10 @@
 
 * Add Drone CI config
 
+### Updates
+
+* Update CHANGELOG for v0.3.13
+
 
 <a name="v0.3.12"></a>
 ## [v0.3.12](https://git.mills.io/prologic/bitcask/compare/v0.3.11...v0.3.12) (2021-07-13)

README.md

@@ -1,17 +1,8 @@
 # bitcask
 
-![](https://git.mills.io/prologic/bitcask/workflows/Coverage/badge.svg)
-![](https://git.mills.io/prologic/bitcask/workflows/Docker/badge.svg)
-![](https://git.mills.io/prologic/bitcask/workflows/Go/badge.svg)
-![](https://git.mills.io/prologic/bitcask/workflows/ReviewDog/badge.svg)
-
-[![CodeCov](https://codecov.io/gh/prologic/bitcask/branch/master/graph/badge.svg)](https://codecov.io/gh/prologic/bitcask)
-[![Go Report Card](https://goreportcard.com/badge/prologic/bitcask)](https://goreportcard.com/report/prologic/bitcask)
-[![codebeat badge](https://codebeat.co/badges/15fba8a5-3044-4f40-936f-9e0f5d5d1fd9)](https://codebeat.co/projects/github-com-prologic-bitcask-master)
-[![GoDoc](https://godoc.org/git.mills.io/prologic/bitcask?status.svg)](https://godoc.org/git.mills.io/prologic/bitcask) 
-[![GitHub license](https://img.shields.io/github/license/prologic/bitcask.svg)](https://git.mills.io/prologic/bitcask)
-[![Sourcegraph](https://sourcegraph.com/git.mills.io/prologic/bitcask/-/badge.svg)](https://sourcegraph.com/git.mills.io/prologic/bitcask?badge)
-[![TODOs](https://img.shields.io/endpoint?url=https://api.tickgit.com/badge?repo=git.mills.io/prologic/bitcask)](https://www.tickgit.com/browse?repo=git.mills.io/prologic/bitcask)
+[![Build Status](https://ci.mills.io/api/badges/prologic/bitcask/status.svg)](https://ci.mills.io/prologic/bitcask)
+[![Go Report Card](https://goreportcard.com/badge/git.mills.io/prologic/bitcask)](https://goreportcard.com/report/git.mills.io/prologic/bitcask)
+[![Go Reference](https://pkg.go.dev/badge/git.mills.io/prologic/bitcask.svg)](https://pkg.go.dev/git.mills.io/prologic/bitcask)
 
 A high performance Key/Value store written in [Go](https://golang.org) with a predictable read/write performance and high throughput. Uses a [Bitcask](https://en.wikipedia.org/wiki/Bitcask) on-disk layout (LSM+WAL) similar to [Riak](https://riak.com/)
 
@@ -229,24 +220,14 @@ Support the ongoing development of Bitcask!
 
 - Become a [Sponsor](https://www.patreon.com/prologic)
 
-## Stargazers over time
-
-[![Stargazers over time](https://starcharts.herokuapp.com/prologic/bitcask.svg)](https://starcharts.herokuapp.com/prologic/bitcask)
-
 ## Contributors
 
-Thank you to all those that have contributed to this project, battle-tested it, used it in their own projects or products, fixed bugs, improved performance and even fix tiny typos in documentation! Thank you and keep contributing!
+Thank you to all those that have contributed to this project, battle-tested it,
+used it in their own projects or products, fixed bugs, improved performance
+and even fix tiny typos in documentation! Thank you and keep contributing!
 
-You can find an [AUTHORS](/AUTHORS) file where we keep a list of contributors to the project. If you contribute a PR please consider adding your name there. There is also GitHub's own [Contributors](https://git.mills.io/prologic/bitcask/graphs/contributors) statistics.
-
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/0)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/0)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/1)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/1)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/2)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/2)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/3)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/3)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/4)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/4)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/5)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/5)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/6)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/6)
-[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/7)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/7)
+You can find an [AUTHORS](/AUTHORS) file where we keep a list of contributors
+to the project. If you contribute a PR please consider adding your name there.
 
 ## Related Projects
 

bitcask.go

@@ -1,6 +1,7 @@
 package bitcask
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"hash/crc32"
@@ -13,6 +14,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/abcum/lcp"
 	"github.com/gofrs/flock"
 	art "github.com/plar/go-adaptive-radix-tree"
 	log "github.com/sirupsen/logrus"
@@ -58,6 +60,7 @@ var (
 	// (typically opened by another process)
 	ErrDatabaseLocked = errors.New("error: database locked")
 
+	ErrInvalidRange   = errors.New("error: invalid range")
 	ErrInvalidVersion = errors.New("error: invalid db version")
 
 	// ErrMergeInProgress is the error returned if merge is called when already a merge
@@ -274,6 +277,39 @@ func (b *Bitcask) delete(key []byte) error {
 	return nil
 }
 
+// Sift iterates over all keys in the database calling the function `f` for
+// each key. If the KV pair is expired or the function returns true, that key is
+// deleted from the database.
+// If the function returns an error on any key, no further keys are processed, no
+// keys are deleted, and the first error is returned.
+func (b *Bitcask) Sift(f func(key []byte) (bool, error)) (err error) {
+	keysToDelete := art.New()
+
+	b.mu.RLock()
+	b.trie.ForEach(func(node art.Node) bool {
+		if b.isExpired(node.Key()) {
+			keysToDelete.Insert(node.Key(), true)
+			return true
+		}
+		var shouldDelete bool
+		if shouldDelete, err = f(node.Key()); err != nil {
+			return false
+		} else if shouldDelete {
+			keysToDelete.Insert(node.Key(), true)
+		}
+		return true
+	})
+	b.mu.RUnlock()
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	keysToDelete.ForEach(func(node art.Node) (cont bool) {
+		b.delete(node.Key())
+		return true
+	})
+	return
+}
+
 // DeleteAll deletes all the keys. If an I/O error occurs the error is returned.
 func (b *Bitcask) DeleteAll() (err error) {
 	b.mu.RLock()
@@ -296,8 +332,11 @@ func (b *Bitcask) DeleteAll() (err error) {
 
 // Scan performs a prefix scan of keys matching the given prefix and calling
 // the function `f` with the keys found. If the function returns an error
-// no further keys are processed and the first error returned.
+// no further keys are processed and the first error is returned.
 func (b *Bitcask) Scan(prefix []byte, f func(key []byte) error) (err error) {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
 	b.trie.ForEachPrefix(prefix, func(node art.Node) bool {
 		// Skip the root node
 		if len(node.Key()) == 0 {
@@ -312,6 +351,124 @@ func (b *Bitcask) Scan(prefix []byte, f func(key []byte) error) (err error) {
 	return
 }
 
+// SiftScan iterates over all keys in the database beginning with the given
+// prefix, calling the function `f` for each key. If the KV pair is expired or
+// the function returns true, that key is deleted from the database.
+//  If the function returns an error on any key, no further keys are processed,
+// no keys are deleted, and the first error is returned.
+func (b *Bitcask) SiftScan(prefix []byte, f func(key []byte) (bool, error)) (err error) {
+	keysToDelete := art.New()
+
+	b.mu.RLock()
+	b.trie.ForEachPrefix(prefix, func(node art.Node) bool {
+		// Skip the root node
+		if len(node.Key()) == 0 {
+			return true
+		}
+		if b.isExpired(node.Key()) {
+			keysToDelete.Insert(node.Key(), true)
+			return true
+		}
+		var shouldDelete bool
+		if shouldDelete, err = f(node.Key()); err != nil {
+			return false
+		} else if shouldDelete {
+			keysToDelete.Insert(node.Key(), true)
+		}
+		return true
+	})
+	b.mu.RUnlock()
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	keysToDelete.ForEach(func(node art.Node) (cont bool) {
+		b.delete(node.Key())
+		return true
+	})
+	return
+}
+
+// Range performs a range scan of keys matching a range of keys between the
+// start key and end key and calling the function `f` with the keys found.
+// If the function returns an error no further keys are processed and the
+// first error returned.
+func (b *Bitcask) Range(start, end []byte, f func(key []byte) error) (err error) {
+	if bytes.Compare(start, end) == 1 {
+		return ErrInvalidRange
+	}
+
+	commonPrefix := lcp.LCP(start, end)
+	if commonPrefix == nil {
+		return ErrInvalidRange
+	}
+
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	b.trie.ForEachPrefix(commonPrefix, func(node art.Node) bool {
+		if bytes.Compare(node.Key(), start) >= 0 && bytes.Compare(node.Key(), end) <= 0 {
+			if err = f(node.Key()); err != nil {
+				return false
+			}
+			return true
+		} else if bytes.Compare(node.Key(), start) >= 0 && bytes.Compare(node.Key(), end) > 0 {
+			return false
+		}
+		return true
+	})
+	return
+}
+
+// SiftRange performs a range scan of keys matching a range of keys between the
+// start key and end key and calling the function `f` with the keys found.
+// If the KV pair is expired or the function returns true, that key is deleted
+// from the database.
+// If the function returns an error on any key, no further keys are processed, no
+// keys are deleted, and the first error is returned.
+func (b *Bitcask) SiftRange(start, end []byte, f func(key []byte) (bool, error)) (err error) {
+	if bytes.Compare(start, end) == 1 {
+		return ErrInvalidRange
+	}
+
+	commonPrefix := lcp.LCP(start, end)
+	if commonPrefix == nil {
+		return ErrInvalidRange
+	}
+
+	keysToDelete := art.New()
+
+	b.mu.RLock()
+	b.trie.ForEachPrefix(commonPrefix, func(node art.Node) bool {
+		if bytes.Compare(node.Key(), start) >= 0 && bytes.Compare(node.Key(), end) <= 0 {
+			if b.isExpired(node.Key()) {
+				keysToDelete.Insert(node.Key(), true)
+				return true
+			}
+			var shouldDelete bool
+			if shouldDelete, err = f(node.Key()); err != nil {
+				return false
+			} else if shouldDelete {
+				keysToDelete.Insert(node.Key(), true)
+			}
+			return true
+		} else if bytes.Compare(node.Key(), start) >= 0 && bytes.Compare(node.Key(), end) > 0 {
+			return false
+		}
+		return true
+	})
+	b.mu.RUnlock()
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	keysToDelete.ForEach(func(node art.Node) (cont bool) {
+		b.delete(node.Key())
+		return true
+	})
+
+	return
+}
+
 // Len returns the total number of keys in the database
 func (b *Bitcask) Len() int {
 	b.mu.RLock()
@@ -349,21 +506,29 @@ func (b *Bitcask) RunGC() error {
 // runGC deletes all keys that are expired
 // caller function should take care of the locking when calling this method
 func (b *Bitcask) runGC() (err error) {
+	keysToDelete := art.New()
+
 	b.ttlIndex.ForEach(func(node art.Node) (cont bool) {
 		if !b.isExpired(node.Key()) {
+			// later, return false here when the ttlIndex is sorted
 			return true
 		}
-		if err = b.delete(node.Key()); err != nil {
-			return false
-		}
+		keysToDelete.Insert(node.Key(), true)
+		//keysToDelete = append(keysToDelete, node.Key())
 		return true
 	})
-	return
+
+	keysToDelete.ForEach(func(node art.Node) (cont bool) {
+		b.delete(node.Key())
+		return true
+	})
+
+	return nil
 }
 
 // Fold iterates over all keys in the database calling the function `f` for
 // each key. If the function returns an error, no further keys are processed
-// and the error returned.
+// and the error is returned.
 func (b *Bitcask) Fold(f func(key []byte) error) (err error) {
 	b.mu.RLock()
 	defer b.mu.RUnlock()
@@ -386,8 +551,7 @@ func (b *Bitcask) get(key []byte) (internal.Entry, error) {
 	if !found {
 		return internal.Entry{}, ErrKeyNotFound
 	}
-	if expired := b.isExpired(key); expired {
-		_ = b.delete(key) // we don't care if it doesnt succeed
+	if b.isExpired(key) {
 		return internal.Entry{}, ErrKeyExpired
 	}
 

bitcask_test.go

@@ -168,6 +168,65 @@ func TestAll(t *testing.T) {
 		assert.NoError(err)
 	})
 
+	t.Run("Sift", func(t *testing.T) {
+		err = db.Put([]byte("toBeSifted"), []byte("siftMe"))
+		assert.NoError(err)
+		err = db.Put([]byte("notToBeSifted"), []byte("dontSiftMe"))
+		assert.NoError(err)
+		err := db.Sift(func(key []byte) (bool, error) {
+			value, err := db.Get(key)
+			if err != nil {
+				return false, err
+			}
+			if string(value) == "siftMe" {
+				return true, nil
+			}
+			return false, nil
+		})
+		assert.NoError(err)
+		_, err = db.Get([]byte("toBeSifted"))
+		assert.Equal(ErrKeyNotFound, err)
+		_, err = db.Get([]byte("notToBeSifted"))
+		assert.NoError(err)
+	})
+
+	t.Run("SiftScan", func(t *testing.T) {
+		err := db.DeleteAll()
+		assert.NoError(err)
+		err = db.Put([]byte("toBeSifted"), []byte("siftMe"))
+		assert.NoError(err)
+		err = db.Put([]byte("toBeSkipped"), []byte("siftMe"))
+		assert.NoError(err)
+		err = db.Put([]byte("toBeSiftedAsWell"), []byte("siftMe"))
+		assert.NoError(err)
+		err = db.Put([]byte("toBeSiftedButNotReally"), []byte("dontSiftMe"))
+		assert.NoError(err)
+		err = db.SiftScan([]byte("toBeSifted"), func(key []byte) (bool, error) {
+			value, err := db.Get(key)
+			if err != nil {
+				return false, err
+			}
+			if string(value) == "siftMe" {
+				return true, nil
+			}
+			return false, nil
+		})
+		assert.NoError(err)
+		_, err = db.Get([]byte("toBeSifted"))
+		assert.Equal(ErrKeyNotFound, err)
+		_, err = db.Get([]byte("toBeSiftedAsWell"))
+		assert.Equal(ErrKeyNotFound, err)
+		_, err = db.Get([]byte("toBeSkipped"))
+		assert.NoError(err)
+		_, err = db.Get([]byte("toBeSiftedButNotReally"))
+		assert.NoError(err)
+	})
+
+	t.Run("DeleteAll", func(t *testing.T) {
+		err = db.DeleteAll()
+		assert.NoError(err)
+	})
+
 	t.Run("Close", func(t *testing.T) {
 		err = db.Close()
 		assert.NoError(err)
@@ -1655,6 +1714,93 @@ func TestConcurrent(t *testing.T) {
 	})
 }
 
+func TestSift(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	var db *Bitcask
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Open", func(t *testing.T) {
+			db, err = Open(testdir)
+			assert.NoError(err)
+		})
+
+		t.Run("Put", func(t *testing.T) {
+			var items = map[string][]byte{
+				"1":     []byte("1"),
+				"2":     []byte("2"),
+				"3":     []byte("3"),
+				"food":  []byte("pizza"),
+				"foo":   []byte([]byte("foo")),
+				"fooz":  []byte("fooz ball"),
+				"hello": []byte("world"),
+			}
+			for k, v := range items {
+				err = db.Put([]byte(k), v)
+				assert.NoError(err)
+			}
+		})
+	})
+
+	t.Run("SiftErrors", func(t *testing.T) {
+		err = db.Sift(func(key []byte) (bool, error) {
+			return false, ErrMockError
+		})
+		assert.Equal(ErrMockError, err)
+
+		err = db.SiftScan([]byte("fo"), func(key []byte) (bool, error) {
+			return true, ErrMockError
+		})
+		assert.Equal(ErrMockError, err)
+	})
+}
+func TestSiftScan(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	var db *Bitcask
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Open", func(t *testing.T) {
+			db, err = Open(testdir)
+			assert.NoError(err)
+		})
+
+		t.Run("Put", func(t *testing.T) {
+			var items = map[string][]byte{
+				"1":     []byte("1"),
+				"2":     []byte("2"),
+				"3":     []byte("3"),
+				"food":  []byte("pizza"),
+				"foo":   []byte([]byte("foo")),
+				"fooz":  []byte("fooz ball"),
+				"hello": []byte("world"),
+			}
+			for k, v := range items {
+				err = db.Put([]byte(k), v)
+				assert.NoError(err)
+			}
+		})
+	})
+
+	t.Run("SiftScanErrors", func(t *testing.T) {
+		err = db.SiftScan([]byte("fo"), func(key []byte) (bool, error) {
+			return false, ErrMockError
+		})
+		assert.Equal(ErrMockError, err)
+
+		err = db.SiftScan([]byte("fo"), func(key []byte) (bool, error) {
+			return true, ErrMockError
+		})
+		assert.Equal(ErrMockError, err)
+	})
+}
+
 func TestScan(t *testing.T) {
 	assert := assert.New(t)
 
@@ -1714,6 +1860,146 @@ func TestScan(t *testing.T) {
 		assert.Equal(ErrMockError, err)
 	})
 }
+func TestSiftRange(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	var db *Bitcask
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Open", func(t *testing.T) {
+			db, err = Open(testdir)
+			assert.NoError(err)
+		})
+
+		t.Run("Put", func(t *testing.T) {
+			for i := 1; i < 10; i++ {
+				key := []byte(fmt.Sprintf("foo_%d", i))
+				val := []byte(fmt.Sprintf("%d", i))
+				err = db.Put(key, val)
+				assert.NoError(err)
+			}
+		})
+	})
+
+	t.Run("SiftRange", func(t *testing.T) {
+		var (
+			vals     [][]byte
+			expected = [][]byte{
+				[]byte("1"),
+				[]byte("2"),
+				[]byte("4"),
+				[]byte("5"),
+				[]byte("6"),
+				[]byte("7"),
+				[]byte("8"),
+				[]byte("9"),
+			}
+		)
+
+		err = db.SiftRange([]byte("foo_3"), []byte("foo_7"), func(key []byte) (bool, error) {
+			val, err := db.Get(key)
+			assert.NoError(err)
+			if string(val) == "3" {
+				return true, nil
+			}
+			return false, nil
+		})
+		err = db.Fold(func(key []byte) error {
+			val, err := db.Get(key)
+			assert.NoError(err)
+			vals = append(vals, val)
+
+			return nil
+		})
+
+		_, err = db.Get([]byte("foo_3"))
+		assert.Equal(ErrKeyNotFound, err)
+		vals = SortByteArrays(vals)
+		assert.Equal(expected, vals)
+	})
+
+	t.Run("SiftRangeErrors", func(t *testing.T) {
+		err = db.SiftRange([]byte("foo_3"), []byte("foo_7"), func(key []byte) (bool, error) {
+			return true, ErrMockError
+		})
+		assert.Error(err)
+		assert.Equal(ErrMockError, err)
+	})
+
+	t.Run("InvalidRange", func(t *testing.T) {
+		err = db.SiftRange([]byte("foo_3"), []byte("foo_1"), func(key []byte) (bool, error) {
+			return false, nil
+		})
+		assert.Error(err)
+		assert.Equal(ErrInvalidRange, err)
+	})
+}
+
+func TestRange(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	var db *Bitcask
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Open", func(t *testing.T) {
+			db, err = Open(testdir)
+			assert.NoError(err)
+		})
+
+		t.Run("Put", func(t *testing.T) {
+			for i := 1; i < 10; i++ {
+				key := []byte(fmt.Sprintf("foo_%d", i))
+				val := []byte(fmt.Sprintf("%d", i))
+				err = db.Put(key, val)
+				assert.NoError(err)
+			}
+		})
+	})
+
+	t.Run("Range", func(t *testing.T) {
+		var (
+			vals     [][]byte
+			expected = [][]byte{
+				[]byte("3"),
+				[]byte("4"),
+				[]byte("5"),
+				[]byte("6"),
+				[]byte("7"),
+			}
+		)
+
+		err = db.Range([]byte("foo_3"), []byte("foo_7"), func(key []byte) error {
+			val, err := db.Get(key)
+			assert.NoError(err)
+			vals = append(vals, val)
+			return nil
+		})
+		vals = SortByteArrays(vals)
+		assert.Equal(expected, vals)
+	})
+
+	t.Run("RangeErrors", func(t *testing.T) {
+		err = db.Range([]byte("foo_3"), []byte("foo_7"), func(key []byte) error {
+			return ErrMockError
+		})
+		assert.Error(err)
+		assert.Equal(ErrMockError, err)
+	})
+
+	t.Run("InvalidRange", func(t *testing.T) {
+		err = db.Range([]byte("foo_3"), []byte("foo_1"), func(key []byte) error {
+			return nil
+		})
+		assert.Error(err)
+		assert.Equal(ErrInvalidRange, err)
+	})
+}
 
 func TestLocking(t *testing.T) {
 	assert := assert.New(t)
@@ -1750,6 +2036,74 @@ func TestLockingAfterMerge(t *testing.T) {
 	assert.Error(err)
 }
 
+func TestGetExpiredInsideFold(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	db, err := Open(testdir)
+	assert.NoError(err)
+	defer db.Close()
+	// Add a node to the tree that won't expire
+	db.Put([]byte("static"), []byte("static"))
+	// Add a node that expires almost immediately to the tree
+	db.PutWithTTL([]byte("shortLived"), []byte("shortLived"), 1*time.Millisecond)
+	db.Put([]byte("skipped"), []byte("skipped"))
+	db.Put([]byte("static2"), []byte("static2"))
+	time.Sleep(2 * time.Millisecond)
+	var arr []string
+	_ = db.Fold(func(key []byte) error {
+		val, err := db.Get(key)
+		switch string(key) {
+		case "skipped":
+			fallthrough
+		case "static2":
+			fallthrough
+		case "static":
+			assert.NoError(err)
+			assert.Equal(string(val), string(key))
+		case "shortLived":
+			assert.Error(err)
+		}
+		arr = append(arr, string(val))
+		return nil
+	})
+	assert.Contains(arr, "skipped")
+}
+
+func TestRunGCDeletesAllExpired(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	db, err := Open(testdir)
+	assert.NoError(err)
+	defer db.Close()
+
+	// Add a node to the tree that won't expire
+	db.Put([]byte("static"), []byte("static"))
+
+	// Add a node that expires almost immediately to the tree
+	db.PutWithTTL([]byte("shortLived"), []byte("shortLived"), 0)
+	db.PutWithTTL([]byte("longLived"), []byte("longLived"), time.Hour)
+	db.PutWithTTL([]byte("longLived2"), []byte("longLived2"), time.Hour)
+	db.PutWithTTL([]byte("shortLived2"), []byte("shortLived2"), 0)
+	db.PutWithTTL([]byte("shortLived3"), []byte("shortLived3"), 0)
+	db.Put([]byte("static2"), []byte("static2"))
+
+	// Sleep a bit and run the Garbage Collector
+	time.Sleep(3 * time.Millisecond)
+	db.RunGC()
+
+	_ = db.Fold(func(key []byte) error {
+		_, err := db.Get(key)
+		assert.NoError(err)
+		return nil
+	})
+}
+
 type benchmarkTestCase struct {
 	name string
 	size int

cmd/bitcask/range.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+
+	"git.mills.io/prologic/bitcask"
+)
+
+var rangeCmd = &cobra.Command{
+	Use:     "range <start> <end>",
+	Aliases: []string{},
+	Short:   "Perform a range scan for keys from a start to end key",
+	Long: `This performa a range scan for keys  starting with the given start
+key and ending with the end key. This uses a Trie to search for matching keys
+within the range and returns all matched keys.`,
+	Args: cobra.ExactArgs(2),
+	Run: func(cmd *cobra.Command, args []string) {
+		path := viper.GetString("path")
+
+		start := args[0]
+		end := args[1]
+
+		os.Exit(_range(path, start, end))
+	},
+}
+
+func init() {
+	RootCmd.AddCommand(rangeCmd)
+}
+
+func _range(path, start, end string) int {
+	db, err := bitcask.Open(path)
+	if err != nil {
+		log.WithError(err).Error("error opening database")
+		return 1
+	}
+	defer db.Close()
+
+	err = db.Range([]byte(start), []byte(end), func(key []byte) error {
+		value, err := db.Get(key)
+		if err != nil {
+			log.WithError(err).Error("error reading key")
+			return err
+		}
+
+		fmt.Printf("%s\n", string(value))
+		log.WithField("key", key).WithField("value", value).Debug("key/value")
+		return nil
+	})
+	if err != nil {
+		log.WithError(err).Error("error ranging over keys")
+		return 1
+	}
+
+	return 0
+}

go.mod

@@ -1,8 +1,9 @@
 module git.mills.io/prologic/bitcask
 
-go 1.13
+go 1.16
 
 require (
+	github.com/abcum/lcp v0.0.0-20201209214815-7a3f3840be81
 	github.com/gofrs/flock v0.8.0
 	github.com/pkg/errors v0.9.1
 	github.com/plar/go-adaptive-radix-tree v1.0.4

go.sum

@@ -40,6 +40,8 @@ dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
+github.com/abcum/lcp v0.0.0-20201209214815-7a3f3840be81 h1:uHogIJ9bXH75ZYrXnVShHIyywFiUZ7OOabwd9Sfd8rw=
+github.com/abcum/lcp v0.0.0-20201209214815-7a3f3840be81/go.mod h1:6ZvnjTZX1LNo1oLpfaJK8h+MXqHxcBFBIwkgsv+xlv0=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
@@ -162,6 +164,7 @@ github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1 h1:EGx4pi6eqNxGaHF6qqu48+N2wcFQ5qg5FXgOdqsJ5d8=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
+github.com/gopherjs/gopherjs v0.0.0-20200217142428-fce0ec30dd00/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
 github.com/grpc-ecosystem/go-grpc-middleware v1.0.0/go.mod h1:FiyG127CGDf3tlThmgyCl78X/SZQqEOJBCDaAfeWzPs=
 github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0/go.mod h1:8NvIoxWQoOIhqOTXgfV/d3M/q6VIi02HzZEHgUlZvzk=
@@ -268,6 +271,7 @@ github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE
 github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
+github.com/smartystreets/assertions v1.2.0/go.mod h1:tcbTF8ujkAEcZ8TElKY+i30BzYlVhC/LOxJk7iOWnoo=
 github.com/smartystreets/goconvey v1.6.4 h1:fv0U8FUIMPNf1L9lnHLvLhgicrIVChEkdzIKYqbNC9s=
 github.com/smartystreets/goconvey v1.6.4/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA=
 github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=