add IndexSz field to TableInfo, to show it through badger info tool

This PR adds the table index size to badger info and adds a new field IndexSz to TableInfo struct. This field denotes the size of the table index

badger/cmd/info.go

@@ -244,13 +244,13 @@ func tableInfo(dir, valueDir string, db *badger.DB) {
 	tables := db.Tables(true)
 	fmt.Println()
 	fmt.Println("SSTable [Li, Id, Total Keys including internal keys] " +
-		"[Left Key, Version -> Right Key, Version]")
+		"[Left Key, Version -> Right Key, Version]" + "[Index Size]")
 	for _, t := range tables {
 		lk, lt := y.ParseKey(t.Left), y.ParseTs(t.Left)
 		rk, rt := y.ParseKey(t.Right), y.ParseTs(t.Right)
 
-		fmt.Printf("SSTable [L%d, %03d, %07d] [%20X, v%d -> %20X, v%d]\n",
-			t.Level, t.ID, t.KeyCount, lk, lt, rk, rt)
+		fmt.Printf("SSTable [L%d, %03d, %07d] [%20X, v%d -> %20X, v%d] [%s]\n",
+			t.Level, t.ID, t.KeyCount, lk, lt, rk, rt, hbytes(int64(t.IndexSz)))
 	}
 	fmt.Println()
 }

levels.go

@@ -1139,6 +1139,7 @@ type TableInfo struct {
 	Right       []byte
 	KeyCount    uint64 // Number of keys in the table
 	EstimatedSz uint64
+	IndexSz     int
 }
 
 func (s *levelsController) getTableInfo(withKeysCount bool) (result []TableInfo) {
@@ -1161,6 +1162,7 @@ func (s *levelsController) getTableInfo(withKeysCount bool) (result []TableInfo)
 				Right:       t.Biggest(),
 				KeyCount:    count,
 				EstimatedSz: t.EstimatedSize(),
+				IndexSz:     t.IndexSize(),
 			}
 			result = append(result, info)
 		}

table/table.go

@@ -647,6 +647,15 @@ func (t *Table) blockOffsetsCacheKey() []byte {
 	return buf
 }
 
+// IndexSize is the size of table index in bytes
+func (t *Table) IndexSize() int {
+	indexSz := 0
+	for _, bi := range t.blockOffsets() {
+		indexSz += bi.Size()
+	}
+	return indexSz
+}
+
 // EstimatedSize returns the total size of key-values stored in this table (including the
 // disk space occupied on the value log).
 func (t *Table) EstimatedSize() uint64 { return t.estimatedSize }