swarm/storage: Batched database migration (#18113)

swarm/storage/ldbstore.go

@@ -284,7 +284,7 @@ func getGCIdxValue(index *dpaDBIndex, po uint8, addr Address) []byte {
 	return val
 }
 
-func parseGCIdxKey(key []byte) (byte, []byte) {
+func parseIdxKey(key []byte) (byte, []byte) {
 	return key[0], key[1:]
 }
 
@@ -589,7 +589,7 @@ func (s *LDBStore) CleanGCIndex() error {
 	it.Seek([]byte{keyGCIdx})
 	var gcDeletes int
 	for it.Valid() {
-		rowType, _ := parseGCIdxKey(it.Key())
+		rowType, _ := parseIdxKey(it.Key())
 		if rowType != keyGCIdx {
 			break
 		}
@@ -601,32 +601,70 @@ func (s *LDBStore) CleanGCIndex() error {
 	if err := s.db.Write(&batch); err != nil {
 		return err
 	}
+	batch.Reset()
 
-	it.Seek([]byte{keyIndex})
-	var idx dpaDBIndex
+	it.Release()
+
+	// corrected po index pointer values
 	var poPtrs [256]uint64
-	for it.Valid() {
-		rowType, chunkHash := parseGCIdxKey(it.Key())
+
+	// set to true if chunk count not on 4096 iteration boundary
+	var doneIterating bool
+
+	// last key index in previous iteration
+	lastIdxKey := []byte{keyIndex}
+
+	// counter for debug output
+	var cleanBatchCount int
+
+	// go through all key index entries
+	for !doneIterating {
+		cleanBatchCount++
+		var idxs []dpaDBIndex
+		var chunkHashes [][]byte
+		var pos []uint8
+		it := s.db.NewIterator()
+
+		it.Seek(lastIdxKey)
+
+		// 4096 is just a nice number, don't look for any hidden meaning here...
+		var i int
+		for i = 0; i < 4096; i++ {
+
+			// this really shouldn't happen unless database is empty
+			// but let's keep it to be safe
+			if !it.Valid() {
+				doneIterating = true
+				break
+			}
+
+			// if it's not keyindex anymore we're done iterating
+			rowType, chunkHash := parseIdxKey(it.Key())
 			if rowType != keyIndex {
+				doneIterating = true
 				break
 			}
+
+			// decode the retrieved index
+			var idx dpaDBIndex
 			err := decodeIndex(it.Value(), &idx)
 			if err != nil {
 				return fmt.Errorf("corrupt index: %v", err)
 			}
 			po := s.po(chunkHash)
+			lastIdxKey = it.Key()
 
 			// if we don't find the data key, remove the entry
+			// if we find it, add to the array of new gc indices to create
 			dataKey := getDataKey(idx.Idx, po)
 			_, err = s.db.Get(dataKey)
 			if err != nil {
 				log.Warn("deleting inconsistent index (missing data)", "key", chunkHash)
 				batch.Delete(it.Key())
 			} else {
-			gcIdxKey := getGCIdxKey(&idx)
-			gcIdxData := getGCIdxValue(&idx, po, chunkHash)
-			batch.Put(gcIdxKey, gcIdxData)
-			log.Trace("clean ok", "key", chunkHash, "gcKey", gcIdxKey, "gcData", gcIdxData)
+				idxs = append(idxs, idx)
+				chunkHashes = append(chunkHashes, chunkHash)
+				pos = append(pos, po)
 				okEntryCount++
 				if idx.Idx > poPtrs[po] {
 					poPtrs[po] = idx.Idx
@@ -635,13 +673,41 @@ func (s *LDBStore) CleanGCIndex() error {
 			totalEntryCount++
 			it.Next()
 		}
-
 		it.Release()
+
+		// flush the key index corrections
+		err := s.db.Write(&batch)
+		if err != nil {
+			return err
+		}
+		batch.Reset()
+
+		// add correct gc indices
+		for i, okIdx := range idxs {
+			gcIdxKey := getGCIdxKey(&okIdx)
+			gcIdxData := getGCIdxValue(&okIdx, pos[i], chunkHashes[i])
+			batch.Put(gcIdxKey, gcIdxData)
+			log.Trace("clean ok", "key", chunkHashes[i], "gcKey", gcIdxKey, "gcData", gcIdxData)
+		}
+
+		// flush them
+		err = s.db.Write(&batch)
+		if err != nil {
+			return err
+		}
+		batch.Reset()
+
+		log.Debug("clean gc index pass", "batch", cleanBatchCount, "checked", i, "kept", len(idxs))
+	}
+
 	log.Debug("gc cleanup entries", "ok", okEntryCount, "total", totalEntryCount, "batchlen", batch.Len())
 
+	// lastly add updated entry count
 	var entryCount [8]byte
 	binary.BigEndian.PutUint64(entryCount[:], okEntryCount)
 	batch.Put(keyEntryCnt, entryCount[:])
+
+	// and add the new po index pointers
 	var poKey [2]byte
 	poKey[0] = keyDistanceCnt
 	for i, poPtr := range poPtrs {
@@ -655,6 +721,7 @@ func (s *LDBStore) CleanGCIndex() error {
 		}
 	}
 
+	// if you made it this far your harddisk has survived. Congratulations
 	return s.db.Write(&batch)
 }
 

swarm/storage/ldbstore_test.go

@@ -761,6 +761,38 @@ func TestCleanIndex(t *testing.T) {
 			t.Fatalf("expected sum of bin indices to be 3, was %d", binTotal)
 		}
 	}
+
+	// check that the iterator quits properly
+	chunks, err = mputRandomChunks(ldb, 4100, 4096)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	po = ldb.po(chunks[4099].Address()[:])
+	dataKey = make([]byte, 10)
+	dataKey[0] = keyData
+	dataKey[1] = byte(po)
+	binary.BigEndian.PutUint64(dataKey[2:], 4099+3)
+	if _, err := ldb.db.Get(dataKey); err != nil {
+		t.Fatal(err)
+	}
+	if err := ldb.db.Delete(dataKey); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := ldb.CleanGCIndex(); err != nil {
+		t.Fatal(err)
+	}
+
+	// entrycount should now be one less of added chunks
+	c, err = ldb.db.Get(keyEntryCnt)
+	if err != nil {
+		t.Fatalf("expected gc 2 idx to be present: %v", idxKey)
+	}
+	entryCount = binary.BigEndian.Uint64(c)
+	if entryCount != 4099+2 {
+		t.Fatalf("expected entrycnt to be 2, was %d", c)
+	}
 }
 
 func waitGc(ctx context.Context, ldb *LDBStore) {