volume: fix memory leak during compaction

fix https://github.com/chrislusf/seaweedfs/issues/1222

weed/storage/erasure_coding/ec_encoder.go

@@ -27,6 +27,9 @@ const (
 func WriteSortedFileFromIdx(baseFileName string, ext string) (e error) {
 
 	nm, err := readNeedleMap(baseFileName)
+	if nm != nil {
+		defer nm.Close()
+	}
 	if err != nil {
 		return fmt.Errorf("readNeedleMap: %v", err)
 	}
@@ -196,7 +199,7 @@ func encodeDatFile(remainingSize int64, err error, baseFileName string, bufferSi
 	}
 
 	buffers := make([][]byte, TotalShardsCount)
-	for i, _ := range buffers {
+	for i := range buffers {
 		buffers[i] = make([]byte, bufferSize)
 	}
 
@@ -233,7 +236,7 @@ func rebuildEcFiles(shardHasData []bool, inputFiles []*os.File, outputFiles []*o
 	}
 
 	buffers := make([][]byte, TotalShardsCount)
-	for i, _ := range buffers {
+	for i := range buffers {
 		if shardHasData[i] {
 			buffers[i] = make([]byte, ErasureCodingSmallBlockSize)
 		}

weed/storage/erasure_coding/ec_test.go

@@ -7,9 +7,10 @@ import (
 	"os"
 	"testing"
 
+	"github.com/klauspost/reedsolomon"
+
 	"github.com/chrislusf/seaweedfs/weed/storage/needle_map"
 	"github.com/chrislusf/seaweedfs/weed/storage/types"
-	"github.com/klauspost/reedsolomon"
 )
 
 const (
@@ -42,6 +43,7 @@ func TestEncodingDecoding(t *testing.T) {
 
 func validateFiles(baseFileName string) error {
 	nm, err := readNeedleMap(baseFileName)
+	defer nm.Close()
 	if err != nil {
 		return fmt.Errorf("readNeedleMap: %v", err)
 	}

weed/storage/needle_map/memdb.go

@@ -113,3 +113,7 @@ func (cm *MemDb) LoadFromIdx(idxName string) (ret error) {
 	})
 
 }
+
+func (cm *MemDb) Close() {
+	cm.db.Close()
+}

weed/storage/needle_map/memdb_test.go

@@ -0,0 +1,23 @@
+package needle_map
+
+import (
+	"testing"
+
+	"github.com/chrislusf/seaweedfs/weed/storage/types"
+)
+
+func BenchmarkMemDb(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		nm := NewMemDb()
+
+		nid := types.NeedleId(345)
+		offset := types.Offset{
+			OffsetHigher: types.OffsetHigher{},
+			OffsetLower:  types.OffsetLower{},
+		}
+		nm.Set(nid, offset, 324)
+		nm.Close()
+	}
+
+}