pruneSnapshot: prune nSnapshotPrune snapshots from the previous 5 days

pruneSnapshot: traverse back using block number instead of hash (which needs to be calculated more costly)

consensus/consortium/v2/consortium.go

@@ -391,7 +391,7 @@ func (c *Consortium) verifyCascadingFields(chain consensus.ChainHeaderReader, he
 		return consortiumCommon.ErrExtraValidators
 	}
 
-	if isTrippEffective{
+	if isTrippEffective {
 		if isEpoch && len(extraData.BlockProducers) == 0 {
 			return consortiumCommon.ErrExtraValidators
 		}
@@ -516,7 +516,7 @@ func (c *Consortium) snapshot(chain consensus.ChainHeaderReader, number uint64,
 			// 	So the final result must be [998: addressN - 1,999: addressN]
 			snap.Recents = consortiumCommon.RemoveOutdatedRecents(snapV1.Recents, number)
 
-			if err := snap.store(c.db); err != nil {
+			if err := snap.store(c.db, chain); err != nil {
 				return nil, err
 			}
 			log.Info("Stored checkpoint snapshot to disk", "number", number, "hash", hash)
@@ -575,7 +575,7 @@ func (c *Consortium) snapshot(chain consensus.ChainHeaderReader, number uint64,
 
 	// If we've generated a new checkpoint snapshot, save to disk
 	if snap.Number%c.config.EpochV2 == 0 && len(headers) > 0 {
-		if err = snap.store(c.db); err != nil {
+		if err = snap.store(c.db, chain); err != nil {
 			return nil, err
 		}
 		log.Trace("Stored snapshot to disk", "number", snap.Number, "hash", snap.Hash)
@@ -1637,7 +1637,7 @@ func (c *Consortium) IsPeriodBlock(chain consensus.ChainHeaderReader, header *ty
 	if c.testTrippPeriod {
 		return true
 	}
-	
+
 	number := header.Number.Uint64()
 	if number%c.config.EpochV2 != 0 || !chain.Config().IsTripp(header.Number) {
 		return false
@@ -1659,7 +1659,7 @@ func (c *Consortium) IsPeriodBlock(chain consensus.ChainHeaderReader, header *ty
 
 // IsTrippEffective returns indicator whether the Tripp consensus rule is effective,
 // which is the first period that is greater than Tripp period, calculated by formula:
-// period := timestamp / dayInSeconds. 
+// period := timestamp / dayInSeconds.
 func (c *Consortium) IsTrippEffective(chain consensus.ChainHeaderReader, header *types.Header) bool {
 	if c.chainConfig.IsTripp(header.Number) {
 		if c.testTrippEffective {

consensus/consortium/v2/snapshot.go

@@ -115,53 +115,43 @@ func loadSnapshot(
 
 // snapshot pruning
 // delete the nSnapshotsPrune oldest snapshots
-func pruneSnapshot(db ethdb.Database, nSnapshotsPrune int) error {
-	// Get all snapshots (hash, block number) from the database
-	nSnapShots := 0
-	snapshots := make(map[common.Hash]uint64)
-	it := db.NewIterator(rawdb.ConsortiumSnapshotPrefix, nil)
-	defer it.Release()
-	for it.Next() {
-		snap := new(Snapshot)
-		if err := json.Unmarshal(it.Value(), snap); err != nil {
-			return err
+func (s *Snapshot) pruneSnapshot(db ethdb.Database, nSnapshotPrune int, chain consensus.ChainHeaderReader) error {
+	log.Info("Pruning snapshots at block", "block", s.Number, "nSnapshotPrune", nSnapshotPrune)
+	// Get block number to start pruning
+	curBlockNumber := s.Number
+	curBlockNumber -= curBlockNumber % 200 // make sure the block number is multiple of 200
+	curBlockNumber -= 200 * 144 * 5        // keep the last 5 days of snapshots
+
+	// delete nSnapshotPrune snapshots starting from curBlockNumber to the older ones
+	batch := db.NewBatch()
+	for nSnapshotPrune > 0 {
+		nSnapshotPrune--
+		header := chain.GetHeaderByNumber(curBlockNumber)
+		if header == nil {
+			// no more snapshots to prune
+			break
 		}
-		snapshots[snap.Hash] = snap.Number
-		nSnapShots++
-	}
-
-	// Sort the snapshots by block number
-	hashes := make([]common.Hash, 0, nSnapShots)
-	for hash := range snapshots {
-		hashes = append(hashes, hash)
-	}
-	sort.Slice(hashes, func(i, j int) bool {
-		return snapshots[hashes[i]] < snapshots[hashes[j]]
-	})
-
-	// Prune the snapshots
-	if nSnapshotsPrune > nSnapShots {
-		nSnapshotsPrune = nSnapShots - 1
-	}
-	for i := 0; i < nSnapshotsPrune; i++ {
-		if err := db.Delete(append(rawdb.ConsortiumSnapshotPrefix, hashes[i][:]...)); err != nil {
+		curHash := header.Hash()
+		if err := batch.Delete(append(rawdb.ConsortiumSnapshotPrefix, curHash[:]...)); err != nil {
 			return err
 		}
+		curBlockNumber -= 200
 	}
-	return nil
+	log.Info("Pruned snapshots done")
+	return batch.Write()
 }
 
 // store inserts the snapshot into the database.
-func (s *Snapshot) store(db ethdb.Database) error {
+func (s *Snapshot) store(db ethdb.Database, chain consensus.ChainHeaderReader) error {
 	blob, err := json.Marshal(s)
 	if err != nil {
 		return err
 	}
 	// prune nSnapshotPrune snapshots every prunePeriod blocks
-	nSnapshotsPrune := 200 * 144 // 1 day
-	prunePeriod := 200 * 144     // 1 day
+	nSnapshotPrune := 144 * 2 // 2 days
+	prunePeriod := 200 * 144  // 1 day
 	if s.Number%uint64(prunePeriod) == 0 {
-		if err := pruneSnapshot(db, nSnapshotsPrune); err != nil {
+		if err := s.pruneSnapshot(db, nSnapshotPrune, chain); err != nil {
 			log.Error("Failed to prune snapshots", "err", err)
 		}
 	}