feat: complete memory keys method

db/memory/db.go

@@ -274,7 +274,36 @@ func (d *Db) Delete(key []byte) error {
 }
 
 func (d *Db) Keys() ([][]byte, error) {
-	panic("implement me")
+	d.mux.RLock()
+	defer d.mux.RUnlock()
+
+	// Create a slice to hold the keys
+	keys := make([][]byte, 0)
+
+	// Collect keys from the active MemTable
+	for key := range d.mem.table {
+		keys = append(keys, []byte(key))
+	}
+
+	// Collect keys from the immutable MemTables (WAL data MemTables)
+	for _, mt := range d.walDataMtList {
+		for key := range mt.table {
+			keys = append(keys, []byte(key))
+		}
+	}
+
+	// Collect keys from the old MemTables (flushed MemTables)
+	for _, mt := range d.oldList {
+		for key := range mt.table {
+			keys = append(keys, []byte(key))
+		}
+	}
+
+	// Collect keys from the persistent storage (your DB implementation)
+	persistentKeys := d.db.GetListKeys()
+	keys = append(keys, persistentKeys...)
+
+	return keys, nil
 }
 
 func (d *Db) Close() error {

db/memory/db_test.go

@@ -38,3 +38,27 @@ func TestPutAndGet(t *testing.T) {
 	end = time.Now()
 	fmt.Println("get time: ", end.Sub(start).String())
 }
+
+func TestDb_Keys(t *testing.T) {
+	err := os.Mkdir("./flydb", os.ModePerm)
+	memOpt := config.DefaultDbMemoryOptions
+	memOpt.LogNum = 100
+	memOpt.FileSize = 256 * 1024 * 1024
+	memOpt.TotalMemSize = 2 * 1024 * 1024 * 1024
+	memOpt.Option.DirPath = "./"
+
+	db, err := NewDB(memOpt)
+	defer db.Clean()
+	assert.Nil(t, err)
+	assert.NotNil(t, db)
+
+	for n := 0; n < 100; n++ {
+		err = db.Put(randkv.GetTestKey(n), randkv.RandomValue(24))
+		assert.Nil(t, err)
+	}
+
+	keys, err := db.Keys()
+	assert.Nil(t, err)
+	assert.Equal(t, 100, len(keys))
+	t.Log(keys)
+}