Add trackers for missing block metadata retroactively

arbnode/transaction_streamer.go

@@ -1207,17 +1207,16 @@ func (s *TransactionStreamer) checkResult(pos arbutil.MessageIndex, msgResult *e
 			"actual", msgResult.BlockHash,
 		)
 		// Try deleting the existing blockMetadata for this block in arbDB and set it as missing
-		if msgAndBlockInfo.BlockMetadata != nil {
+		if msgAndBlockInfo.BlockMetadata != nil &&
+			s.trackBlockMetadataFrom != 0 && pos >= s.trackBlockMetadataFrom {
 			batch := s.db.NewBatch()
 			if err := batch.Delete(dbKey(blockMetadataInputFeedPrefix, uint64(pos))); err != nil {
 				log.Error("error deleting blockMetadata of block whose BlockHash from feed doesn't match locally computed hash", "msgSeqNum", pos, "err", err)
 				return
 			}
-			if s.trackBlockMetadataFrom != 0 && pos >= s.trackBlockMetadataFrom {
-				if err := batch.Put(dbKey(missingBlockMetadataInputFeedPrefix, uint64(pos)), nil); err != nil {
-					log.Error("error marking deleted blockMetadata as missing in arbDB for a block whose BlockHash from feed doesn't match locally computed hash", "msgSeqNum", pos, "err", err)
-					return
-				}
+			if err := batch.Put(dbKey(missingBlockMetadataInputFeedPrefix, uint64(pos)), nil); err != nil {
+				log.Error("error marking deleted blockMetadata as missing in arbDB for a block whose BlockHash from feed doesn't match locally computed hash", "msgSeqNum", pos, "err", err)
+				return
 			}
 			if err := batch.Write(); err != nil {
 				log.Error("error writing batch that deletes blockMetadata of the block whose BlockHash from feed doesn't match locally computed hash", "msgSeqNum", pos, "err", err)
@@ -1320,7 +1319,71 @@ func (s *TransactionStreamer) executeMessages(ctx context.Context, ignored struc
 	return s.config().ExecuteMessageLoopDelay
 }
 
+func (s *TransactionStreamer) backfillTrackersForMissingBlockMetadata(ctx context.Context) {
+	if s.trackBlockMetadataFrom == 0 {
+		return
+	}
+	msgCount, err := s.GetMessageCount()
+	if err != nil {
+		log.Error("Error getting message count from arbDB", "err", err)
+		return
+	}
+	if s.trackBlockMetadataFrom >= msgCount {
+		return // We dont need to back fill if trackBlockMetadataFrom is in the future
+	}
+
+	wasKeyFound := func(pos uint64, prefix []byte) bool {
+		key := dbKey(prefix, pos)
+		_, err := s.db.Get(key)
+		if err == nil {
+			return true
+		}
+		if !dbutil.IsErrNotFound(err) {
+			log.Error("Error reading key in arbDB while back-filling trackers for missing blockMetadata", "key", key, "err", err)
+		}
+		return false
+	}
+
+	start := s.trackBlockMetadataFrom
+	finish := msgCount - 1
+	for start < finish {
+		mid := (start + finish + 1) / 2
+		if wasKeyFound(uint64(mid), blockMetadataInputFeedPrefix) ||
+			wasKeyFound(uint64(mid), missingBlockMetadataInputFeedPrefix) {
+			finish = mid - 1
+		} else {
+			start = mid
+		}
+	}
+	if wasKeyFound(uint64(start), blockMetadataInputFeedPrefix) ||
+		wasKeyFound(uint64(start), missingBlockMetadataInputFeedPrefix) {
+		return // back-filling not required
+	}
+	lastNonExistent := start
+
+	// We back-fill in reverse to avoid fragmentation in case of any failures
+	batch := s.db.NewBatch()
+	for i := lastNonExistent; i >= s.trackBlockMetadataFrom; i-- {
+		if err := batch.Put(dbKey(missingBlockMetadataInputFeedPrefix, uint64(i)), nil); err != nil {
+			log.Error("Error marking blockMetadata as missing while back-filling", "pos", i, "err", err)
+			return
+		}
+		// If we reached the ideal batch size, commit and reset
+		if batch.ValueSize() >= ethdb.IdealBatchSize {
+			if err := batch.Write(); err != nil {
+				log.Error("Error writing batch with missing trackers to db while back-filling", "err", err)
+				return
+			}
+			batch.Reset()
+		}
+	}
+	if err := batch.Write(); err != nil {
+		log.Error("Error writing batch with missing trackers to db while back-filling", "err", err)
+	}
+}
+
 func (s *TransactionStreamer) Start(ctxIn context.Context) error {
 	s.StopWaiter.Start(ctxIn, s)
+	s.LaunchThread(s.backfillTrackersForMissingBlockMetadata)
 	return stopwaiter.CallIterativelyWith[struct{}](&s.StopWaiterSafe, s.executeMessages, s.newMessageNotifier)
 }

arbnode/tx_streamer_test.go

@@ -0,0 +1,67 @@
+package arbnode
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/rlp"
+
+	"github.com/offchainlabs/nitro/arbutil"
+)
+
+func TestTimeboostBackfillingsTrackersForMissingBlockMetadata(t *testing.T) {
+	t.Parallel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	messageCount := uint64(20)
+
+	// Create arbDB with fragmented blockMetadata across blocks
+	arbDb := rawdb.NewMemoryDatabase()
+	countBytes, err := rlp.EncodeToBytes(messageCount)
+	Require(t, err)
+	Require(t, arbDb.Put(messageCountKey, countBytes))
+	addKeys := func(start, end uint64, prefix []byte) {
+		for i := start; i <= end; i++ {
+			Require(t, arbDb.Put(dbKey(prefix, i), []byte{}))
+		}
+	}
+	// 12, 13, 14, 18 have block metadata
+	addKeys(12, 14, blockMetadataInputFeedPrefix)
+	addKeys(18, 18, blockMetadataInputFeedPrefix)
+	// 15, 16, 17, 19 are missing
+	addKeys(15, 17, missingBlockMetadataInputFeedPrefix)
+	addKeys(19, 19, missingBlockMetadataInputFeedPrefix)
+
+	// Create tx streamer
+	txStreamer := &TransactionStreamer{db: arbDb}
+	txStreamer.StopWaiter.Start(ctx, txStreamer)
+
+	backfillAndVerifyCorrectness := func(trackBlockMetadataFrom arbutil.MessageIndex, missingTrackers []uint64) {
+		txStreamer.trackBlockMetadataFrom = trackBlockMetadataFrom
+		txStreamer.backfillTrackersForMissingBlockMetadata(ctx)
+		iter := arbDb.NewIterator([]byte("x"), nil)
+		pos := 0
+		for iter.Next() {
+			keyBytes := bytes.TrimPrefix(iter.Key(), missingBlockMetadataInputFeedPrefix)
+			if binary.BigEndian.Uint64(keyBytes) != missingTrackers[pos] {
+				t.Fatalf("unexpected presence of blockMetadata. msgSeqNum: %d, expectedMsgSeqNum: %d", binary.BigEndian.Uint64(keyBytes), missingTrackers[pos])
+			}
+			pos++
+		}
+		if pos != len(missingTrackers) {
+			t.Fatalf("number of keys with blockMetadataInputFeedPrefix doesn't match expected value. Want: %d, Got: %d", len(missingTrackers), pos)
+		}
+		iter.Release()
+	}
+
+	// Backfill trackers for missing data and verify that 10, 11 get added to already existing 16, 17, 18, 19 keys
+	backfillAndVerifyCorrectness(10, []uint64{10, 11, 15, 16, 17, 19})
+
+	// Backfill trackers for missing data and verify that 5, 6, 7, 8, 9 get added to already existing 10, 11, 16, 17, 18, 19 keys
+	backfillAndVerifyCorrectness(5, []uint64{5, 6, 7, 8, 9, 10, 11, 15, 16, 17, 19})
+}