fix: remove mutex in prefixdb

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- remove mutex from prefixdb
+
 ## 0.6.7
 
 **2022-2-21**

boltdb.go

@@ -1,3 +1,4 @@
+//go:build boltdb
 // +build boltdb
 
 package db

boltdb_batch.go

@@ -1,3 +1,4 @@
+//go:build boltdb
 // +build boltdb
 
 package db

boltdb_iterator.go

@@ -1,3 +1,4 @@
+//go:build boltdb
 // +build boltdb
 
 package db

boltdb_test.go

@@ -1,3 +1,4 @@
+//go:build boltdb
 // +build boltdb
 
 package db

cleveldb.go

@@ -1,3 +1,4 @@
+//go:build cleveldb
 // +build cleveldb
 
 package db

cleveldb_batch.go

@@ -1,3 +1,4 @@
+//go:build cleveldb
 // +build cleveldb
 
 package db

cleveldb_iterator.go

@@ -1,3 +1,4 @@
+//go:build cleveldb
 // +build cleveldb
 
 package db

cleveldb_test.go

@@ -1,3 +1,4 @@
+//go:build cleveldb
 // +build cleveldb
 
 package db

db_test.go

@@ -94,6 +94,7 @@ func TestDBIteratorMany(t *testing.T) {
 	}
 }
 
+
 func TestDBIteratorEmpty(t *testing.T) {
 	for backend := range backends {
 		t.Run(fmt.Sprintf("Backend %s", backend), func(t *testing.T) {

prefixdb.go

@@ -27,8 +27,8 @@ func (pdb *PrefixDB) Get(key []byte) ([]byte, error) {
 	if len(key) == 0 {
 		return nil, errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
+	// pdb.mtx.Lock()
+	// defer pdb.mtx.Unlock()
 
 	pkey := pdb.prefixed(key)
 	value, err := pdb.db.Get(pkey)
@@ -43,8 +43,6 @@ func (pdb *PrefixDB) Has(key []byte) (bool, error) {
 	if len(key) == 0 {
 		return false, errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	ok, err := pdb.db.Has(pdb.prefixed(key))
 	if err != nil {
@@ -62,8 +60,6 @@ func (pdb *PrefixDB) Set(key []byte, value []byte) error {
 	if value == nil {
 		return errValueNil
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	pkey := pdb.prefixed(key)
 	if err := pdb.db.Set(pkey, value); err != nil {
@@ -80,8 +76,6 @@ func (pdb *PrefixDB) SetSync(key []byte, value []byte) error {
 	if value == nil {
 		return errValueNil
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	return pdb.db.SetSync(pdb.prefixed(key), value)
 }
@@ -91,8 +85,6 @@ func (pdb *PrefixDB) Delete(key []byte) error {
 	if len(key) == 0 {
 		return errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	return pdb.db.Delete(pdb.prefixed(key))
 }
@@ -102,8 +94,6 @@ func (pdb *PrefixDB) DeleteSync(key []byte) error {
 	if len(key) == 0 {
 		return errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	return pdb.db.DeleteSync(pdb.prefixed(key))
 }
@@ -113,8 +103,6 @@ func (pdb *PrefixDB) Iterator(start, end []byte) (Iterator, error) {
 	if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
 		return nil, errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	var pstart, pend []byte
 	pstart = append(cp(pdb.prefix), start...)
@@ -136,8 +124,6 @@ func (pdb *PrefixDB) ReverseIterator(start, end []byte) (Iterator, error) {
 	if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
 		return nil, errKeyEmpty
 	}
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	var pstart, pend []byte
 	pstart = append(cp(pdb.prefix), start...)
@@ -156,8 +142,6 @@ func (pdb *PrefixDB) ReverseIterator(start, end []byte) (Iterator, error) {
 
 // NewBatch implements DB.
 func (pdb *PrefixDB) NewBatch() Batch {
-	pdb.mtx.Lock()
-	defer pdb.mtx.Unlock()
 
 	return newPrefixBatch(pdb.prefix, pdb.db.NewBatch())
 }

prefixdb_test.go

@@ -1,6 +1,11 @@
 package db
 
 import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"math/rand"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -20,6 +25,93 @@ func mockDBWithStuff(t *testing.T) DB {
 	return db
 }
 
+func taskKey(i, k uint32) []byte {
+
+	ibyte := make([]byte, 4)
+	binary.LittleEndian.PutUint32(ibyte, i)
+
+	kbyte := make([]byte, 4)
+	binary.LittleEndian.PutUint32(kbyte, i)
+
+	return append(ibyte, kbyte...)
+}
+
+func randomValue() []byte {
+	b := make([]byte, 16)
+	_, err := rand.Read(b)
+
+	if err != nil {
+		return nil
+	}
+
+	return b
+}
+
+// Run generates concurrent reads and writes to db so the race detector can
+// verify concurrent operations are properly synchronized.
+// The contents of db are garbage after Run returns.
+func Run(t *testing.T) {
+
+	db := mockDBWithStuff(t)
+	t.Helper()
+
+	const numWorkers = 10
+	const numKeys = 32
+
+	var wg sync.WaitGroup
+	for i := 0; i < numWorkers; i++ {
+		wg.Add(1)
+		i := i
+		go func() {
+			defer wg.Done()
+
+			// Insert a bunch of keys with random data.
+			for k := 1; k <= numKeys; k++ {
+				key := taskKey(uint32(i), uint32(k)) // say, "task-<i>-key-<k>"
+				value := randomValue()
+				if err := db.Set(key, value); err != nil {
+					t.Errorf("Task %d: db.Set(%q=%q) failed: %v",
+						i, string(key), string(value), err)
+				}
+			}
+
+			// Iterate over the database to make sure our keys are there.
+			it, err := db.Iterator(nil, nil)
+			if err != nil {
+				t.Errorf("Iterator[%d]: %v", i, err)
+				return
+			}
+			found := make(map[string][]byte)
+			mine := []byte(fmt.Sprintf("task-%d-", i))
+			for it.Valid() {
+				it.Next()
+				if key := it.Key(); bytes.HasPrefix(key, mine) {
+					found[string(key)] = it.Value()
+				}
+			}
+			if err := it.Error(); err != nil {
+				t.Errorf("Iterator[%d] reported error: %v", i, err)
+			}
+			if err := it.Close(); err != nil {
+				t.Errorf("Close iterator[%d]: %v", i, err)
+			}
+			if len(mine) != numKeys {
+				t.Errorf("Task %d: found %d keys, wanted %d", i, len(mine), numKeys)
+			}
+
+			// Delete all the keys we inserted.
+			for key := range mine {
+				bs := make([]byte, 4)
+				binary.LittleEndian.PutUint32(bs, uint32(key))
+				if err := db.Delete(bs); err != nil {
+					t.Errorf("Delete %q: %v", key, err)
+				}
+			}
+		}()
+	}
+	wg.Wait()
+}
+
 func TestPrefixDBSimple(t *testing.T) {
 	db := mockDBWithStuff(t)
 	pdb := NewPrefixDB(db, bz("key"))

rocksdb.go

@@ -1,3 +1,4 @@
+//go:build rocksdb
 // +build rocksdb
 
 package db

rocksdb_batch.go

@@ -1,3 +1,4 @@
+//go:build rocksdb
 // +build rocksdb
 
 package db

rocksdb_iterator.go

@@ -1,3 +1,4 @@
+//go:build rocksdb
 // +build rocksdb
 
 package db

rocksdb_test.go

@@ -1,3 +1,4 @@
+//go:build rocksdb
 // +build rocksdb
 
 package db