Merge pull request #19244 from karalabe/freezer-2

cmd, core, eth, les, node: chain freezer on top of db rework

15 files changed, 2753 insertions, 208 deletions

diff --git a/core/blockchain.go b/core/blockchain.go
index 61b809319..7ab6806c2 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -63,6 +63,8 @@ var (
 
 	blockPrefetchExecuteTimer   = metrics.NewRegisteredTimer("chain/prefetch/executes", nil)
 	blockPrefetchInterruptMeter = metrics.NewRegisteredMeter("chain/prefetch/interrupts", nil)
+
+	errInsertionInterrupted = errors.New("insertion is interrupted")
 )
 
 const (
@@ -91,7 +93,10 @@ const (
 	// - Version 6
 	//  The following incompatible database changes were added:
 	//    * Transaction lookup information stores the corresponding block number instead of block hash
-	BlockChainVersion uint64 = 6
+	// - Version 7
+	//  The following incompatible database changes were added:
+	//    * Use freezer as the ancient database to maintain all ancient data
+	BlockChainVersion uint64 = 7
 )
 
 // CacheConfig contains the configuration values for the trie caching/pruning
@@ -138,7 +143,6 @@ type BlockChain struct {
 
 	chainmu sync.RWMutex // blockchain insertion lock
 
-	checkpoint       int          // checkpoint counts towards the new checkpoint
 	currentBlock     atomic.Value // Current head of the block chain
 	currentFastBlock atomic.Value // Current head of the fast-sync chain (may be above the block chain!)
 
@@ -161,8 +165,9 @@ type BlockChain struct {
 	processor  Processor  // Block transaction processor interface
 	vmConfig   vm.Config
 
-	badBlocks      *lru.Cache              // Bad block cache
-	shouldPreserve func(*types.Block) bool // Function used to determine whether should preserve the given block.
+	badBlocks       *lru.Cache                     // Bad block cache
+	shouldPreserve  func(*types.Block) bool        // Function used to determine whether should preserve the given block.
+	terminateInsert func(common.Hash, uint64) bool // Testing hook used to terminate ancient receipt chain insertion.
 }
 
 // NewBlockChain returns a fully initialised block chain using information
@@ -213,9 +218,82 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 	if bc.genesisBlock == nil {
 		return nil, ErrNoGenesis
 	}
+	// Initialize the chain with ancient data if it isn't empty.
+	if bc.empty() {
+		if frozen, err := bc.db.Ancients(); err == nil && frozen > 0 {
+			var (
+				start  = time.Now()
+				logged time.Time
+			)
+			for i := uint64(0); i < frozen; i++ {
+				// Inject hash<->number mapping.
+				hash := rawdb.ReadCanonicalHash(bc.db, i)
+				if hash == (common.Hash{}) {
+					return nil, errors.New("broken ancient database")
+				}
+				rawdb.WriteHeaderNumber(bc.db, hash, i)
+
+				// Inject txlookup indexes.
+				block := rawdb.ReadBlock(bc.db, hash, i)
+				if block == nil {
+					return nil, errors.New("broken ancient database")
+				}
+				rawdb.WriteTxLookupEntries(bc.db, block)
+
+				// If we've spent too much time already, notify the user of what we're doing
+				if time.Since(logged) > 8*time.Second {
+					log.Info("Initializing chain from ancient data", "number", i, "hash", hash, "total", frozen-1, "elapsed", common.PrettyDuration(time.Since(start)))
+					logged = time.Now()
+				}
+			}
+			hash := rawdb.ReadCanonicalHash(bc.db, frozen-1)
+			rawdb.WriteHeadHeaderHash(bc.db, hash)
+			rawdb.WriteHeadFastBlockHash(bc.db, hash)
+
+			// The first thing the node will do is reconstruct the verification data for
+			// the head block (ethash cache or clique voting snapshot). Might as well do
+			// it in advance.
+			bc.engine.VerifyHeader(bc, rawdb.ReadHeader(bc.db, hash, frozen-1), true)
+
+			log.Info("Initialized chain from ancient data", "number", frozen-1, "hash", hash, "elapsed", common.PrettyDuration(time.Since(start)))
+		}
+	}
 	if err := bc.loadLastState(); err != nil {
 		return nil, err
 	}
+	if frozen, err := bc.db.Ancients(); err == nil && frozen > 0 {
+		var (
+			needRewind bool
+			low        uint64
+		)
+		// The head full block may be rolled back to a very low height due to
+		// blockchain repair. If the head full block is even lower than the ancient
+		// chain, truncate the ancient store.
+		fullBlock := bc.CurrentBlock()
+		if fullBlock != nil && fullBlock != bc.genesisBlock && fullBlock.NumberU64() < frozen-1 {
+			needRewind = true
+			low = fullBlock.NumberU64()
+		}
+		// In fast sync, it may happen that ancient data has been written to the
+		// ancient store, but the LastFastBlock has not been updated, truncate the
+		// extra data here.
+		fastBlock := bc.CurrentFastBlock()
+		if fastBlock != nil && fastBlock.NumberU64() < frozen-1 {
+			needRewind = true
+			if fastBlock.NumberU64() < low || low == 0 {
+				low = fastBlock.NumberU64()
+			}
+		}
+		if needRewind {
+			var hashes []common.Hash
+			previous := bc.CurrentHeader().Number.Uint64()
+			for i := low + 1; i <= bc.CurrentHeader().Number.Uint64(); i++ {
+				hashes = append(hashes, rawdb.ReadCanonicalHash(bc.db, i))
+			}
+			bc.Rollback(hashes)
+			log.Warn("Truncate ancient chain", "from", previous, "to", low)
+		}
+	}
 	// Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain
 	for hash := range BadHashes {
 		if header := bc.GetHeaderByHash(hash); header != nil {
@@ -243,6 +321,20 @@ func (bc *BlockChain) GetVMConfig() *vm.Config {
 	return &bc.vmConfig
 }
 
+// empty returns an indicator whether the blockchain is empty.
+// Note, it's a special case that we connect a non-empty ancient
+// database with an empty node, so that we can plugin the ancient
+// into node seamlessly.
+func (bc *BlockChain) empty() bool {
+	genesis := bc.genesisBlock.Hash()
+	for _, hash := range []common.Hash{rawdb.ReadHeadBlockHash(bc.db), rawdb.ReadHeadHeaderHash(bc.db), rawdb.ReadHeadFastBlockHash(bc.db)} {
+		if hash != genesis {
+			return false
+		}
+	}
+	return true
+}
+
 // loadLastState loads the last known chain state from the database. This method
 // assumes that the chain manager mutex is held.
 func (bc *BlockChain) loadLastState() error {
@@ -267,6 +359,7 @@ func (bc *BlockChain) loadLastState() error {
 		if err := bc.repair(&currentBlock); err != nil {
 			return err
 		}
+		rawdb.WriteHeadBlockHash(bc.db, currentBlock.Hash())
 	}
 	// Everything seems to be fine, set as the head block
 	bc.currentBlock.Store(currentBlock)
@@ -312,12 +405,57 @@ func (bc *BlockChain) SetHead(head uint64) error {
 	bc.chainmu.Lock()
 	defer bc.chainmu.Unlock()
 
+	updateFn := func(db ethdb.KeyValueWriter, header *types.Header) {
+		// Rewind the block chain, ensuring we don't end up with a stateless head block
+		if currentBlock := bc.CurrentBlock(); currentBlock != nil && header.Number.Uint64() < currentBlock.NumberU64() {
+			newHeadBlock := bc.GetBlock(header.Hash(), header.Number.Uint64())
+			if newHeadBlock == nil {
+				newHeadBlock = bc.genesisBlock
+			} else {
+				if _, err := state.New(newHeadBlock.Root(), bc.stateCache); err != nil {
+					// Rewound state missing, rolled back to before pivot, reset to genesis
+					newHeadBlock = bc.genesisBlock
+				}
+			}
+			rawdb.WriteHeadBlockHash(db, newHeadBlock.Hash())
+			bc.currentBlock.Store(newHeadBlock)
+		}
+
+		// Rewind the fast block in a simpleton way to the target head
+		if currentFastBlock := bc.CurrentFastBlock(); currentFastBlock != nil && header.Number.Uint64() < currentFastBlock.NumberU64() {
+			newHeadFastBlock := bc.GetBlock(header.Hash(), header.Number.Uint64())
+			// If either blocks reached nil, reset to the genesis state
+			if newHeadFastBlock == nil {
+				newHeadFastBlock = bc.genesisBlock
+			}
+			rawdb.WriteHeadFastBlockHash(db, newHeadFastBlock.Hash())
+			bc.currentFastBlock.Store(newHeadFastBlock)
+		}
+	}
+
 	// Rewind the header chain, deleting all block bodies until then
-	delFn := func(db ethdb.Writer, hash common.Hash, num uint64) {
-		rawdb.DeleteBody(db, hash, num)
+	delFn := func(db ethdb.KeyValueWriter, hash common.Hash, num uint64) {
+		// Ignore the error here since light client won't hit this path
+		frozen, _ := bc.db.Ancients()
+		if num+1 <= frozen {
+			// Truncate all relative data(header, total difficulty, body, receipt
+			// and canonical hash) from ancient store.
+			if err := bc.db.TruncateAncients(num + 1); err != nil {
+				log.Crit("Failed to truncate ancient data", "number", num, "err", err)
+			}
+
+			// Remove the hash <-> number mapping from the active store.
+			rawdb.DeleteHeaderNumber(db, hash)
+		} else {
+			// Remove relative body and receipts from the active store.
+			// The header, total difficulty and canonical hash will be
+			// removed in the hc.SetHead function.
+			rawdb.DeleteBody(db, hash, num)
+			rawdb.DeleteReceipts(db, hash, num)
+		}
+		// Todo(rjl493456442) txlookup, bloombits, etc
 	}
-	bc.hc.SetHead(head, delFn)
-	currentHeader := bc.hc.CurrentHeader()
+	bc.hc.SetHead(head, updateFn, delFn)
 
 	// Clear out any stale content from the caches
 	bc.bodyCache.Purge()
@@ -326,33 +464,6 @@ func (bc *BlockChain) SetHead(head uint64) error {
 	bc.blockCache.Purge()
 	bc.futureBlocks.Purge()
 
-	// Rewind the block chain, ensuring we don't end up with a stateless head block
-	if currentBlock := bc.CurrentBlock(); currentBlock != nil && currentHeader.Number.Uint64() < currentBlock.NumberU64() {
-		bc.currentBlock.Store(bc.GetBlock(currentHeader.Hash(), currentHeader.Number.Uint64()))
-	}
-	if currentBlock := bc.CurrentBlock(); currentBlock != nil {
-		if _, err := state.New(currentBlock.Root(), bc.stateCache); err != nil {
-			// Rewound state missing, rolled back to before pivot, reset to genesis
-			bc.currentBlock.Store(bc.genesisBlock)
-		}
-	}
-	// Rewind the fast block in a simpleton way to the target head
-	if currentFastBlock := bc.CurrentFastBlock(); currentFastBlock != nil && currentHeader.Number.Uint64() < currentFastBlock.NumberU64() {
-		bc.currentFastBlock.Store(bc.GetBlock(currentHeader.Hash(), currentHeader.Number.Uint64()))
-	}
-	// If either blocks reached nil, reset to the genesis state
-	if currentBlock := bc.CurrentBlock(); currentBlock == nil {
-		bc.currentBlock.Store(bc.genesisBlock)
-	}
-	if currentFastBlock := bc.CurrentFastBlock(); currentFastBlock == nil {
-		bc.currentFastBlock.Store(bc.genesisBlock)
-	}
-	currentBlock := bc.CurrentBlock()
-	currentFastBlock := bc.CurrentFastBlock()
-
-	rawdb.WriteHeadBlockHash(bc.db, currentBlock.Hash())
-	rawdb.WriteHeadFastBlockHash(bc.db, currentFastBlock.Hash())
-
 	return bc.loadLastState()
 }
 
@@ -780,96 +891,272 @@ func (bc *BlockChain) Rollback(chain []common.Hash) {
 		}
 		if currentFastBlock := bc.CurrentFastBlock(); currentFastBlock.Hash() == hash {
 			newFastBlock := bc.GetBlock(currentFastBlock.ParentHash(), currentFastBlock.NumberU64()-1)
-			bc.currentFastBlock.Store(newFastBlock)
 			rawdb.WriteHeadFastBlockHash(bc.db, newFastBlock.Hash())
+			bc.currentFastBlock.Store(newFastBlock)
 		}
 		if currentBlock := bc.CurrentBlock(); currentBlock.Hash() == hash {
 			newBlock := bc.GetBlock(currentBlock.ParentHash(), currentBlock.NumberU64()-1)
-			bc.currentBlock.Store(newBlock)
 			rawdb.WriteHeadBlockHash(bc.db, newBlock.Hash())
+			bc.currentBlock.Store(newBlock)
 		}
 	}
+	// Truncate ancient data which exceeds the current header.
+	//
+	// Notably, it can happen that system crashes without truncating the ancient data
+	// but the head indicator has been updated in the active store. Regarding this issue,
+	// system will self recovery by truncating the extra data during the setup phase.
+	if err := bc.truncateAncient(bc.hc.CurrentHeader().Number.Uint64()); err != nil {
+		log.Crit("Truncate ancient store failed", "err", err)
+	}
+}
+
+// truncateAncient rewinds the blockchain to the specified header and deletes all
+// data in the ancient store that exceeds the specified header.
+func (bc *BlockChain) truncateAncient(head uint64) error {
+	frozen, err := bc.db.Ancients()
+	if err != nil {
+		return err
+	}
+	// Short circuit if there is no data to truncate in ancient store.
+	if frozen <= head+1 {
+		return nil
+	}
+	// Truncate all the data in the freezer beyond the specified head
+	if err := bc.db.TruncateAncients(head + 1); err != nil {
+		return err
+	}
+	// Clear out any stale content from the caches
+	bc.hc.headerCache.Purge()
+	bc.hc.tdCache.Purge()
+	bc.hc.numberCache.Purge()
+
+	// Clear out any stale content from the caches
+	bc.bodyCache.Purge()
+	bc.bodyRLPCache.Purge()
+	bc.receiptsCache.Purge()
+	bc.blockCache.Purge()
+	bc.futureBlocks.Purge()
+
+	log.Info("Rewind ancient data", "number", head)
+	return nil
 }
 
 // InsertReceiptChain attempts to complete an already existing header chain with
 // transaction and receipt data.
-func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
+func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain []types.Receipts, ancientLimit uint64) (int, error) {
 	bc.wg.Add(1)
 	defer bc.wg.Done()
 
+	var (
+		ancientBlocks, liveBlocks     types.Blocks
+		ancientReceipts, liveReceipts []types.Receipts
+	)
 	// Do a sanity check that the provided chain is actually ordered and linked
-	for i := 1; i < len(blockChain); i++ {
-		if blockChain[i].NumberU64() != blockChain[i-1].NumberU64()+1 || blockChain[i].ParentHash() != blockChain[i-1].Hash() {
-			log.Error("Non contiguous receipt insert", "number", blockChain[i].Number(), "hash", blockChain[i].Hash(), "parent", blockChain[i].ParentHash(),
-				"prevnumber", blockChain[i-1].Number(), "prevhash", blockChain[i-1].Hash())
-			return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, blockChain[i-1].NumberU64(),
-				blockChain[i-1].Hash().Bytes()[:4], i, blockChain[i].NumberU64(), blockChain[i].Hash().Bytes()[:4], blockChain[i].ParentHash().Bytes()[:4])
+	for i := 0; i < len(blockChain); i++ {
+		if i != 0 {
+			if blockChain[i].NumberU64() != blockChain[i-1].NumberU64()+1 || blockChain[i].ParentHash() != blockChain[i-1].Hash() {
+				log.Error("Non contiguous receipt insert", "number", blockChain[i].Number(), "hash", blockChain[i].Hash(), "parent", blockChain[i].ParentHash(),
+					"prevnumber", blockChain[i-1].Number(), "prevhash", blockChain[i-1].Hash())
+				return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, blockChain[i-1].NumberU64(),
+					blockChain[i-1].Hash().Bytes()[:4], i, blockChain[i].NumberU64(), blockChain[i].Hash().Bytes()[:4], blockChain[i].ParentHash().Bytes()[:4])
+			}
+		}
+		if blockChain[i].NumberU64() <= ancientLimit {
+			ancientBlocks, ancientReceipts = append(ancientBlocks, blockChain[i]), append(ancientReceipts, receiptChain[i])
+		} else {
+			liveBlocks, liveReceipts = append(liveBlocks, blockChain[i]), append(liveReceipts, receiptChain[i])
 		}
 	}
 
 	var (
 		stats = struct{ processed, ignored int32 }{}
 		start = time.Now()
-		bytes = 0
-		batch = bc.db.NewBatch()
+		size  = 0
 	)
-	for i, block := range blockChain {
-		receipts := receiptChain[i]
-		// Short circuit insertion if shutting down or processing failed
-		if atomic.LoadInt32(&bc.procInterrupt) == 1 {
-			return 0, nil
+	// updateHead updates the head fast sync block if the inserted blocks are better
+	// and returns a indicator whether the inserted blocks are canonical.
+	updateHead := func(head *types.Block) bool {
+		var isCanonical bool
+		bc.chainmu.Lock()
+		if td := bc.GetTd(head.Hash(), head.NumberU64()); td != nil { // Rewind may have occurred, skip in that case
+			currentFastBlock := bc.CurrentFastBlock()
+			if bc.GetTd(currentFastBlock.Hash(), currentFastBlock.NumberU64()).Cmp(td) < 0 {
+				rawdb.WriteHeadFastBlockHash(bc.db, head.Hash())
+				bc.currentFastBlock.Store(head)
+				isCanonical = true
+			}
+		}
+		bc.chainmu.Unlock()
+		return isCanonical
+	}
+	// writeAncient writes blockchain and corresponding receipt chain into ancient store.
+	//
+	// this function only accepts canonical chain data. All side chain will be reverted
+	// eventually.
+	writeAncient := func(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
+		var (
+			previous = bc.CurrentFastBlock()
+			batch    = bc.db.NewBatch()
+		)
+		// If any error occurs before updating the head or we are inserting a side chain,
+		// all the data written this time wll be rolled back.
+		defer func() {
+			if previous != nil {
+				if err := bc.truncateAncient(previous.NumberU64()); err != nil {
+					log.Crit("Truncate ancient store failed", "err", err)
+				}
+			}
+		}()
+		var deleted types.Blocks
+		for i, block := range blockChain {
+			// Short circuit insertion if shutting down or processing failed
+			if atomic.LoadInt32(&bc.procInterrupt) == 1 {
+				return 0, errInsertionInterrupted
+			}
+			// Short circuit insertion if it is required(used in testing only)
+			if bc.terminateInsert != nil && bc.terminateInsert(block.Hash(), block.NumberU64()) {
+				return i, errors.New("insertion is terminated for testing purpose")
+			}
+			// Short circuit if the owner header is unknown
+			if !bc.HasHeader(block.Hash(), block.NumberU64()) {
+				return i, fmt.Errorf("containing header #%d [%x…] unknown", block.Number(), block.Hash().Bytes()[:4])
+			}
+			var (
+				start  = time.Now()
+				logged = time.Now()
+				count  int
+			)
+			// Migrate all ancient blocks. This can happen if someone upgrades from Geth
+			// 1.8.x to 1.9.x mid-fast-sync. Perhaps we can get rid of this path in the
+			// long term.
+			for {
+				// We can ignore the error here since light client won't hit this code path.
+				frozen, _ := bc.db.Ancients()
+				if frozen >= block.NumberU64() {
+					break
+				}
+				h := rawdb.ReadCanonicalHash(bc.db, frozen)
+				b := rawdb.ReadBlock(bc.db, h, frozen)
+				size += rawdb.WriteAncientBlock(bc.db, b, rawdb.ReadReceipts(bc.db, h, frozen, bc.chainConfig), rawdb.ReadTd(bc.db, h, frozen))
+				count += 1
+
+				// Always keep genesis block in active database.
+				if b.NumberU64() != 0 {
+					deleted = append(deleted, b)
+				}
+				if time.Since(logged) > 8*time.Second {
+					log.Info("Migrating ancient blocks", "count", count, "elapsed", common.PrettyDuration(time.Since(start)))
+					logged = time.Now()
+				}
+			}
+			if count > 0 {
+				log.Info("Migrated ancient blocks", "count", count, "elapsed", common.PrettyDuration(time.Since(start)))
+			}
+			// Flush data into ancient database.
+			size += rawdb.WriteAncientBlock(bc.db, block, receiptChain[i], bc.GetTd(block.Hash(), block.NumberU64()))
+			rawdb.WriteTxLookupEntries(batch, block)
+
+			stats.processed++
 		}
-		// Short circuit if the owner header is unknown
-		if !bc.HasHeader(block.Hash(), block.NumberU64()) {
-			return i, fmt.Errorf("containing header #%d [%x…] unknown", block.Number(), block.Hash().Bytes()[:4])
+		// Flush all tx-lookup index data.
+		size += batch.ValueSize()
+		if err := batch.Write(); err != nil {
+			return 0, err
 		}
-		// Skip if the entire data is already known
-		if bc.HasBlock(block.Hash(), block.NumberU64()) {
-			stats.ignored++
-			continue
+		batch.Reset()
+
+		// Sync the ancient store explicitly to ensure all data has been flushed to disk.
+		if err := bc.db.Sync(); err != nil {
+			return 0, err
 		}
-		// Compute all the non-consensus fields of the receipts
-		if err := receipts.DeriveFields(bc.chainConfig, block.Hash(), block.NumberU64(), block.Transactions()); err != nil {
-			return i, fmt.Errorf("failed to derive receipts data: %v", err)
+		if !updateHead(blockChain[len(blockChain)-1]) {
+			return 0, errors.New("side blocks can't be accepted as the ancient chain data")
 		}
-		// Write all the data out into the database
-		rawdb.WriteBody(batch, block.Hash(), block.NumberU64(), block.Body())
-		rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receipts)
-		rawdb.WriteTxLookupEntries(batch, block)
+		previous = nil // disable rollback explicitly
 
-		stats.processed++
+		// Wipe out canonical block data.
+		for _, block := range append(deleted, blockChain...) {
+			rawdb.DeleteBlockWithoutNumber(batch, block.Hash(), block.NumberU64())
+			rawdb.DeleteCanonicalHash(batch, block.NumberU64())
+		}
+		if err := batch.Write(); err != nil {
+			return 0, err
+		}
+		batch.Reset()
 
-		if batch.ValueSize() >= ethdb.IdealBatchSize {
-			if err := batch.Write(); err != nil {
-				return 0, err
+		// Wipe out side chain too.
+		for _, block := range append(deleted, blockChain...) {
+			for _, hash := range rawdb.ReadAllHashes(bc.db, block.NumberU64()) {
+				rawdb.DeleteBlock(batch, hash, block.NumberU64())
 			}
-			bytes += batch.ValueSize()
-			batch.Reset()
 		}
-	}
-	if batch.ValueSize() > 0 {
-		bytes += batch.ValueSize()
 		if err := batch.Write(); err != nil {
 			return 0, err
 		}
+		return 0, nil
 	}
+	// writeLive writes blockchain and corresponding receipt chain into active store.
+	writeLive := func(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
+		batch := bc.db.NewBatch()
+		for i, block := range blockChain {
+			// Short circuit insertion if shutting down or processing failed
+			if atomic.LoadInt32(&bc.procInterrupt) == 1 {
+				return 0, errInsertionInterrupted
+			}
+			// Short circuit if the owner header is unknown
+			if !bc.HasHeader(block.Hash(), block.NumberU64()) {
+				return i, fmt.Errorf("containing header #%d [%x…] unknown", block.Number(), block.Hash().Bytes()[:4])
+			}
+			if bc.HasBlock(block.Hash(), block.NumberU64()) {
+				stats.ignored++
+				continue
+			}
+			// Write all the data out into the database
+			rawdb.WriteBody(batch, block.Hash(), block.NumberU64(), block.Body())
+			rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receiptChain[i])
+			rawdb.WriteTxLookupEntries(batch, block)
 
-	// Update the head fast sync block if better
-	bc.chainmu.Lock()
-	head := blockChain[len(blockChain)-1]
-	if td := bc.GetTd(head.Hash(), head.NumberU64()); td != nil { // Rewind may have occurred, skip in that case
-		currentFastBlock := bc.CurrentFastBlock()
-		if bc.GetTd(currentFastBlock.Hash(), currentFastBlock.NumberU64()).Cmp(td) < 0 {
-			rawdb.WriteHeadFastBlockHash(bc.db, head.Hash())
-			bc.currentFastBlock.Store(head)
+			stats.processed++
+			if batch.ValueSize() >= ethdb.IdealBatchSize {
+				if err := batch.Write(); err != nil {
+					return 0, err
+				}
+				size += batch.ValueSize()
+				batch.Reset()
+			}
+		}
+		if batch.ValueSize() > 0 {
+			size += batch.ValueSize()
+			if err := batch.Write(); err != nil {
+				return 0, err
+			}
+		}
+		updateHead(blockChain[len(blockChain)-1])
+		return 0, nil
+	}
+	// Write downloaded chain data and corresponding receipt chain data.
+	if len(ancientBlocks) > 0 {
+		if n, err := writeAncient(ancientBlocks, ancientReceipts); err != nil {
+			if err == errInsertionInterrupted {
+				return 0, nil
+			}
+			return n, err
+		}
+	}
+	if len(liveBlocks) > 0 {
+		if n, err := writeLive(liveBlocks, liveReceipts); err != nil {
+			if err == errInsertionInterrupted {
+				return 0, nil
+			}
+			return n, err
 		}
 	}
-	bc.chainmu.Unlock()
 
+	head := blockChain[len(blockChain)-1]
 	context := []interface{}{
 		"count", stats.processed, "elapsed", common.PrettyDuration(time.Since(start)),
 		"number", head.Number(), "hash", head.Hash(), "age", common.PrettyAge(time.Unix(int64(head.Time()), 0)),
-		"size", common.StorageSize(bytes),
+		"size", common.StorageSize(size),
 	}
 	if stats.ignored > 0 {
 		context = append(context, []interface{}{"ignored", stats.ignored}...)
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index 70e3207f5..8dfcda6d4 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -18,8 +18,10 @@ package core
 
 import (
 	"fmt"
+	"io/ioutil"
 	"math/big"
 	"math/rand"
+	"os"
 	"sync"
 	"testing"
 	"time"
@@ -33,7 +35,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/ethdb/memorydb"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -639,7 +640,27 @@ func TestFastVsFullChains(t *testing.T) {
 	if n, err := fast.InsertHeaderChain(headers, 1); err != nil {
 		t.Fatalf("failed to insert header %d: %v", n, err)
 	}
-	if n, err := fast.InsertReceiptChain(blocks, receipts); err != nil {
+	if n, err := fast.InsertReceiptChain(blocks, receipts, 0); err != nil {
+		t.Fatalf("failed to insert receipt %d: %v", n, err)
+	}
+	// Freezer style fast import the chain.
+	frdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer dir: %v", err)
+	}
+	defer os.Remove(frdir)
+	ancientDb, err := rawdb.NewDatabaseWithFreezer(rawdb.NewMemoryDatabase(), frdir, "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer db: %v", err)
+	}
+	gspec.MustCommit(ancientDb)
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
+	defer ancient.Stop()
+
+	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
+		t.Fatalf("failed to insert header %d: %v", n, err)
+	}
+	if n, err := ancient.InsertReceiptChain(blocks, receipts, uint64(len(blocks)/2)); err != nil {
 		t.Fatalf("failed to insert receipt %d: %v", n, err)
 	}
 	// Iterate over all chain data components, and cross reference
@@ -647,26 +668,35 @@ func TestFastVsFullChains(t *testing.T) {
 		num, hash := blocks[i].NumberU64(), blocks[i].Hash()
 
 		if ftd, atd := fast.GetTdByHash(hash), archive.GetTdByHash(hash); ftd.Cmp(atd) != 0 {
-			t.Errorf("block #%d [%x]: td mismatch: have %v, want %v", num, hash, ftd, atd)
+			t.Errorf("block #%d [%x]: td mismatch: fastdb %v, archivedb %v", num, hash, ftd, atd)
+		}
+		if antd, artd := ancient.GetTdByHash(hash), archive.GetTdByHash(hash); antd.Cmp(artd) != 0 {
+			t.Errorf("block #%d [%x]: td mismatch: ancientdb %v, archivedb %v", num, hash, antd, artd)
 		}
 		if fheader, aheader := fast.GetHeaderByHash(hash), archive.GetHeaderByHash(hash); fheader.Hash() != aheader.Hash() {
-			t.Errorf("block #%d [%x]: header mismatch: have %v, want %v", num, hash, fheader, aheader)
+			t.Errorf("block #%d [%x]: header mismatch: fastdb %v, archivedb %v", num, hash, fheader, aheader)
 		}
-		if fblock, ablock := fast.GetBlockByHash(hash), archive.GetBlockByHash(hash); fblock.Hash() != ablock.Hash() {
-			t.Errorf("block #%d [%x]: block mismatch: have %v, want %v", num, hash, fblock, ablock)
-		} else if types.DeriveSha(fblock.Transactions()) != types.DeriveSha(ablock.Transactions()) {
-			t.Errorf("block #%d [%x]: transactions mismatch: have %v, want %v", num, hash, fblock.Transactions(), ablock.Transactions())
-		} else if types.CalcUncleHash(fblock.Uncles()) != types.CalcUncleHash(ablock.Uncles()) {
-			t.Errorf("block #%d [%x]: uncles mismatch: have %v, want %v", num, hash, fblock.Uncles(), ablock.Uncles())
+		if anheader, arheader := ancient.GetHeaderByHash(hash), archive.GetHeaderByHash(hash); anheader.Hash() != arheader.Hash() {
+			t.Errorf("block #%d [%x]: header mismatch: ancientdb %v, archivedb %v", num, hash, anheader, arheader)
 		}
-		if freceipts, areceipts := rawdb.ReadReceipts(fastDb, hash, *rawdb.ReadHeaderNumber(fastDb, hash), fast.Config()), rawdb.ReadReceipts(archiveDb, hash, *rawdb.ReadHeaderNumber(archiveDb, hash), archive.Config()); types.DeriveSha(freceipts) != types.DeriveSha(areceipts) {
-			t.Errorf("block #%d [%x]: receipts mismatch: have %v, want %v", num, hash, freceipts, areceipts)
+		if fblock, arblock, anblock := fast.GetBlockByHash(hash), archive.GetBlockByHash(hash), ancient.GetBlockByHash(hash); fblock.Hash() != arblock.Hash() || anblock.Hash() != arblock.Hash() {
+			t.Errorf("block #%d [%x]: block mismatch: fastdb %v, ancientdb %v, archivedb %v", num, hash, fblock, anblock, arblock)
+		} else if types.DeriveSha(fblock.Transactions()) != types.DeriveSha(arblock.Transactions()) || types.DeriveSha(anblock.Transactions()) != types.DeriveSha(arblock.Transactions()) {
+			t.Errorf("block #%d [%x]: transactions mismatch: fastdb %v, ancientdb %v, archivedb %v", num, hash, fblock.Transactions(), anblock.Transactions(), arblock.Transactions())
+		} else if types.CalcUncleHash(fblock.Uncles()) != types.CalcUncleHash(arblock.Uncles()) || types.CalcUncleHash(anblock.Uncles()) != types.CalcUncleHash(arblock.Uncles()) {
+			t.Errorf("block #%d [%x]: uncles mismatch: fastdb %v, ancientdb %v, archivedb %v", num, hash, fblock.Uncles(), anblock, arblock.Uncles())
+		}
+		if freceipts, anreceipts, areceipts := rawdb.ReadReceipts(fastDb, hash, *rawdb.ReadHeaderNumber(fastDb, hash), fast.Config()), rawdb.ReadReceipts(ancientDb, hash, *rawdb.ReadHeaderNumber(ancientDb, hash), fast.Config()), rawdb.ReadReceipts(archiveDb, hash, *rawdb.ReadHeaderNumber(archiveDb, hash), fast.Config()); types.DeriveSha(freceipts) != types.DeriveSha(areceipts) {
+			t.Errorf("block #%d [%x]: receipts mismatch: fastdb %v, ancientdb %v, archivedb %v", num, hash, freceipts, anreceipts, areceipts)
 		}
 	}
 	// Check that the canonical chains are the same between the databases
 	for i := 0; i < len(blocks)+1; i++ {
 		if fhash, ahash := rawdb.ReadCanonicalHash(fastDb, uint64(i)), rawdb.ReadCanonicalHash(archiveDb, uint64(i)); fhash != ahash {
-			t.Errorf("block #%d: canonical hash mismatch: have %v, want %v", i, fhash, ahash)
+			t.Errorf("block #%d: canonical hash mismatch: fastdb %v, archivedb %v", i, fhash, ahash)
+		}
+		if anhash, arhash := rawdb.ReadCanonicalHash(ancientDb, uint64(i)), rawdb.ReadCanonicalHash(archiveDb, uint64(i)); anhash != arhash {
+			t.Errorf("block #%d: canonical hash mismatch: ancientdb %v, archivedb %v", i, anhash, arhash)
 		}
 	}
 }
@@ -686,6 +716,20 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	height := uint64(1024)
 	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, int(height), nil)
 
+	// makeDb creates a db instance for testing.
+	makeDb := func() (ethdb.Database, func()) {
+		dir, err := ioutil.TempDir("", "")
+		if err != nil {
+			t.Fatalf("failed to create temp freezer dir: %v", err)
+		}
+		defer os.Remove(dir)
+		db, err := rawdb.NewDatabaseWithFreezer(rawdb.NewMemoryDatabase(), dir, "")
+		if err != nil {
+			t.Fatalf("failed to create temp freezer db: %v", err)
+		}
+		gspec.MustCommit(db)
+		return db, func() { os.RemoveAll(dir) }
+	}
 	// Configure a subchain to roll back
 	remove := []common.Hash{}
 	for _, block := range blocks[height/2:] {
@@ -704,9 +748,8 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 		}
 	}
 	// Import the chain as an archive node and ensure all pointers are updated
-	archiveDb := rawdb.NewMemoryDatabase()
-	gspec.MustCommit(archiveDb)
-
+	archiveDb, delfn := makeDb()
+	defer delfn()
 	archive, _ := NewBlockChain(archiveDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
 	if n, err := archive.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to process block %d: %v", n, err)
@@ -718,8 +761,8 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	assert(t, "archive", archive, height/2, height/2, height/2)
 
 	// Import the chain as a non-archive node and ensure all pointers are updated
-	fastDb := rawdb.NewMemoryDatabase()
-	gspec.MustCommit(fastDb)
+	fastDb, delfn := makeDb()
+	defer delfn()
 	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
 	defer fast.Stop()
 
@@ -730,17 +773,35 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	if n, err := fast.InsertHeaderChain(headers, 1); err != nil {
 		t.Fatalf("failed to insert header %d: %v", n, err)
 	}
-	if n, err := fast.InsertReceiptChain(blocks, receipts); err != nil {
+	if n, err := fast.InsertReceiptChain(blocks, receipts, 0); err != nil {
 		t.Fatalf("failed to insert receipt %d: %v", n, err)
 	}
 	assert(t, "fast", fast, height, height, 0)
 	fast.Rollback(remove)
 	assert(t, "fast", fast, height/2, height/2, 0)
 
-	// Import the chain as a light node and ensure all pointers are updated
-	lightDb := rawdb.NewMemoryDatabase()
-	gspec.MustCommit(lightDb)
+	// Import the chain as a ancient-first node and ensure all pointers are updated
+	ancientDb, delfn := makeDb()
+	defer delfn()
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
+	defer ancient.Stop()
+
+	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
+		t.Fatalf("failed to insert header %d: %v", n, err)
+	}
+	if n, err := ancient.InsertReceiptChain(blocks, receipts, uint64(3*len(blocks)/4)); err != nil {
+		t.Fatalf("failed to insert receipt %d: %v", n, err)
+	}
+	assert(t, "ancient", ancient, height, height, 0)
+	ancient.Rollback(remove)
+	assert(t, "ancient", ancient, height/2, height/2, 0)
+	if frozen, err := ancientDb.Ancients(); err != nil || frozen != height/2+1 {
+		t.Fatalf("failed to truncate ancient store, want %v, have %v", height/2+1, frozen)
+	}
 
+	// Import the chain as a light node and ensure all pointers are updated
+	lightDb, delfn := makeDb()
+	defer delfn()
 	light, _ := NewBlockChain(lightDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
 	if n, err := light.InsertHeaderChain(headers, 1); err != nil {
 		t.Fatalf("failed to insert header %d: %v", n, err)
@@ -918,7 +979,7 @@ func TestLogRebirth(t *testing.T) {
 	var (
 		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
-		db      = memorydb.New()
+		db      = rawdb.NewMemoryDatabase()
 
 		// this code generates a log
 		code     = common.Hex2Bytes("60606040525b7f24ec1d3ff24c2f6ff210738839dbc339cd45a5294d85c79361016243157aae7b60405180905060405180910390a15b600a8060416000396000f360606040526008565b00")
@@ -1040,7 +1101,7 @@ func TestSideLogRebirth(t *testing.T) {
 	var (
 		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
-		db      = memorydb.New()
+		db      = rawdb.NewMemoryDatabase()
 
 		// this code generates a log
 		code     = common.Hex2Bytes("60606040525b7f24ec1d3ff24c2f6ff210738839dbc339cd45a5294d85c79361016243157aae7b60405180905060405180910390a15b600a8060416000396000f360606040526008565b00")
@@ -1564,6 +1625,119 @@ func TestLargeReorgTrieGC(t *testing.T) {
 	}
 }
 
+func TestBlockchainRecovery(t *testing.T) {
+	// Configure and generate a sample block chain
+	var (
+		gendb   = rawdb.NewMemoryDatabase()
+		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		address = crypto.PubkeyToAddress(key.PublicKey)
+		funds   = big.NewInt(1000000000)
+		gspec   = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{address: {Balance: funds}}}
+		genesis = gspec.MustCommit(gendb)
+	)
+	height := uint64(1024)
+	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, int(height), nil)
+
+	// Import the chain as a ancient-first node and ensure all pointers are updated
+	frdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer dir: %v", err)
+	}
+	defer os.Remove(frdir)
+	ancientDb, err := rawdb.NewDatabaseWithFreezer(rawdb.NewMemoryDatabase(), frdir, "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer db: %v", err)
+	}
+	gspec.MustCommit(ancientDb)
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
+
+	headers := make([]*types.Header, len(blocks))
+	for i, block := range blocks {
+		headers[i] = block.Header()
+	}
+	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
+		t.Fatalf("failed to insert header %d: %v", n, err)
+	}
+	if n, err := ancient.InsertReceiptChain(blocks, receipts, uint64(3*len(blocks)/4)); err != nil {
+		t.Fatalf("failed to insert receipt %d: %v", n, err)
+	}
+	ancient.Stop()
+
+	// Destroy head fast block manually
+	midBlock := blocks[len(blocks)/2]
+	rawdb.WriteHeadFastBlockHash(ancientDb, midBlock.Hash())
+
+	// Reopen broken blockchain again
+	ancient, _ = NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
+	defer ancient.Stop()
+	if num := ancient.CurrentBlock().NumberU64(); num != 0 {
+		t.Errorf("head block mismatch: have #%v, want #%v", num, 0)
+	}
+	if num := ancient.CurrentFastBlock().NumberU64(); num != midBlock.NumberU64() {
+		t.Errorf("head fast-block mismatch: have #%v, want #%v", num, midBlock.NumberU64())
+	}
+	if num := ancient.CurrentHeader().Number.Uint64(); num != midBlock.NumberU64() {
+		t.Errorf("head header mismatch: have #%v, want #%v", num, midBlock.NumberU64())
+	}
+}
+
+func TestIncompleteAncientReceiptChainInsertion(t *testing.T) {
+	// Configure and generate a sample block chain
+	var (
+		gendb   = rawdb.NewMemoryDatabase()
+		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		address = crypto.PubkeyToAddress(key.PublicKey)
+		funds   = big.NewInt(1000000000)
+		gspec   = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{address: {Balance: funds}}}
+		genesis = gspec.MustCommit(gendb)
+	)
+	height := uint64(1024)
+	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, int(height), nil)
+
+	// Import the chain as a ancient-first node and ensure all pointers are updated
+	frdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer dir: %v", err)
+	}
+	defer os.Remove(frdir)
+	ancientDb, err := rawdb.NewDatabaseWithFreezer(rawdb.NewMemoryDatabase(), frdir, "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer db: %v", err)
+	}
+	gspec.MustCommit(ancientDb)
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil)
+	defer ancient.Stop()
+
+	headers := make([]*types.Header, len(blocks))
+	for i, block := range blocks {
+		headers[i] = block.Header()
+	}
+	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
+		t.Fatalf("failed to insert header %d: %v", n, err)
+	}
+	// Abort ancient receipt chain insertion deliberately
+	ancient.terminateInsert = func(hash common.Hash, number uint64) bool {
+		return number == blocks[len(blocks)/2].NumberU64()
+	}
+	previousFastBlock := ancient.CurrentFastBlock()
+	if n, err := ancient.InsertReceiptChain(blocks, receipts, uint64(3*len(blocks)/4)); err == nil {
+		t.Fatalf("failed to insert receipt %d: %v", n, err)
+	}
+	if ancient.CurrentFastBlock().NumberU64() != previousFastBlock.NumberU64() {
+		t.Fatalf("failed to rollback ancient data, want %d, have %d", previousFastBlock.NumberU64(), ancient.CurrentFastBlock().NumberU64())
+	}
+	if frozen, err := ancient.db.Ancients(); err != nil || frozen != 1 {
+		t.Fatalf("failed to truncate ancient data")
+	}
+	ancient.terminateInsert = nil
+	if n, err := ancient.InsertReceiptChain(blocks, receipts, uint64(3*len(blocks)/4)); err != nil {
+		t.Fatalf("failed to insert receipt %d: %v", n, err)
+	}
+	if ancient.CurrentFastBlock().NumberU64() != blocks[len(blocks)-1].NumberU64() {
+		t.Fatalf("failed to insert ancient recept chain after rollback")
+	}
+}
+
 // Tests that importing a very large side fork, which is larger than the canon chain,
 // but where the difficulty per block is kept low: this means that it will not
 // overtake the 'canon' chain until after it's passed canon by about 200 blocks.
@@ -1719,10 +1893,18 @@ func testInsertKnownChainData(t *testing.T, typ string) {
 		b.SetCoinbase(common.Address{1})
 		b.OffsetTime(-9) // A higher difficulty
 	})
-
 	// Import the shared chain and the original canonical one
-	chaindb := rawdb.NewMemoryDatabase()
+	dir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer dir: %v", err)
+	}
+	defer os.Remove(dir)
+	chaindb, err := rawdb.NewDatabaseWithFreezer(rawdb.NewMemoryDatabase(), dir, "")
+	if err != nil {
+		t.Fatalf("failed to create temp freezer db: %v", err)
+	}
 	new(Genesis).MustCommit(chaindb)
+	defer os.RemoveAll(dir)
 
 	chain, err := NewBlockChain(chaindb, nil, params.TestChainConfig, engine, vm.Config{}, nil)
 	if err != nil {
@@ -1764,7 +1946,7 @@ func testInsertKnownChainData(t *testing.T, typ string) {
 			if err != nil {
 				return err
 			}
-			_, err = chain.InsertReceiptChain(blocks, receipts)
+			_, err = chain.InsertReceiptChain(blocks, receipts, 0)
 			return err
 		}
 		asserter = func(t *testing.T, block *types.Block) {
@@ -1819,18 +2001,16 @@ func testInsertKnownChainData(t *testing.T, typ string) {
 	// The head shouldn't change.
 	asserter(t, blocks3[len(blocks3)-1])
 
-	if typ != "headers" {
-		// Rollback the heavier chain and re-insert the longer chain again
-		for i := 0; i < len(blocks3); i++ {
-			rollback = append(rollback, blocks3[i].Hash())
-		}
-		chain.Rollback(rollback)
+	// Rollback the heavier chain and re-insert the longer chain again
+	for i := 0; i < len(blocks3); i++ {
+		rollback = append(rollback, blocks3[i].Hash())
+	}
+	chain.Rollback(rollback)
 
-		if err := inserter(append(blocks, blocks2...), append(receipts, receipts2...)); err != nil {
-			t.Fatalf("failed to insert chain data: %v", err)
-		}
-		asserter(t, blocks2[len(blocks2)-1])
+	if err := inserter(append(blocks, blocks2...), append(receipts, receipts2...)); err != nil {
+		t.Fatalf("failed to insert chain data: %v", err)
 	}
+	asserter(t, blocks2[len(blocks2)-1])
 }
 
 // getLongAndShortChains returns two chains,
@@ -2019,14 +2199,12 @@ func BenchmarkBlockChain_1x1000ValueTransferToNonexisting(b *testing.B) {
 		numTxs    = 1000
 		numBlocks = 1
 	)
-
 	recipientFn := func(nonce uint64) common.Address {
 		return common.BigToAddress(big.NewInt(0).SetUint64(1337 + nonce))
 	}
 	dataFn := func(nonce uint64) []byte {
 		return nil
 	}
-
 	benchmarkLargeNumberOfValueToNonexisting(b, numTxs, numBlocks, recipientFn, dataFn)
 }
 
@@ -2044,7 +2222,6 @@ func BenchmarkBlockChain_1x1000ValueTransferToExisting(b *testing.B) {
 	dataFn := func(nonce uint64) []byte {
 		return nil
 	}
-
 	benchmarkLargeNumberOfValueToNonexisting(b, numTxs, numBlocks, recipientFn, dataFn)
 }
 
@@ -2062,6 +2239,5 @@ func BenchmarkBlockChain_1x1000Executions(b *testing.B) {
 	dataFn := func(nonce uint64) []byte {
 		return nil
 	}
-
 	benchmarkLargeNumberOfValueToNonexisting(b, numTxs, numBlocks, recipientFn, dataFn)
 }
diff --git a/core/genesis.go b/core/genesis.go
index 1f34a3a9e..830fb033b 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -170,6 +170,22 @@ func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, constant
 		return genesis.Config, block.Hash(), err
 	}
 
+	// We have the genesis block in database(perhaps in ancient database)
+	// but the corresponding state is missing.
+	header := rawdb.ReadHeader(db, stored, 0)
+	if _, err := state.New(header.Root, state.NewDatabaseWithCache(db, 0)); err != nil {
+		if genesis == nil {
+			genesis = DefaultGenesisBlock()
+		}
+		// Ensure the stored genesis matches with the given one.
+		hash := genesis.ToBlock(nil).Hash()
+		if hash != stored {
+			return genesis.Config, hash, &GenesisMismatchError{stored, hash}
+		}
+		block, err := genesis.Commit(db)
+		return genesis.Config, block.Hash(), err
+	}
+
 	// Check whether the genesis block is already written.
 	if genesis != nil {
 		hash := genesis.ToBlock(nil).Hash()
@@ -277,6 +293,7 @@ func (g *Genesis) Commit(db ethdb.Database) (*types.Block, error) {
 	rawdb.WriteReceipts(db, block.Hash(), block.NumberU64(), nil)
 	rawdb.WriteCanonicalHash(db, block.Hash(), block.NumberU64())
 	rawdb.WriteHeadBlockHash(db, block.Hash())
+	rawdb.WriteHeadFastBlockHash(db, block.Hash())
 	rawdb.WriteHeadHeaderHash(db, block.Hash())
 
 	config := g.Config
diff --git a/core/headerchain.go b/core/headerchain.go
index d0c1987fb..cdd64bb50 100644
--- a/core/headerchain.go
+++ b/core/headerchain.go
@@ -274,9 +274,14 @@ func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, writeHeader WhCa
 			return i, errors.New("aborted")
 		}
 		// If the header's already known, skip it, otherwise store
-		if hc.HasHeader(header.Hash(), header.Number.Uint64()) {
-			stats.ignored++
-			continue
+		hash := header.Hash()
+		if hc.HasHeader(hash, header.Number.Uint64()) {
+			externTd := hc.GetTd(hash, header.Number.Uint64())
+			localTd := hc.GetTd(hc.currentHeaderHash, hc.CurrentHeader().Number.Uint64())
+			if externTd == nil || externTd.Cmp(localTd) <= 0 {
+				stats.ignored++
+				continue
+			}
 		}
 		if err := writeHeader(header); err != nil {
 			return i, err
@@ -453,33 +458,56 @@ func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
 	hc.currentHeaderHash = head.Hash()
 }
 
-// DeleteCallback is a callback function that is called by SetHead before
-// each header is deleted.
-type DeleteCallback func(ethdb.Writer, common.Hash, uint64)
+type (
+	// UpdateHeadBlocksCallback is a callback function that is called by SetHead
+	// before head header is updated.
+	UpdateHeadBlocksCallback func(ethdb.KeyValueWriter, *types.Header)
+
+	// DeleteBlockContentCallback is a callback function that is called by SetHead
+	// before each header is deleted.
+	DeleteBlockContentCallback func(ethdb.KeyValueWriter, common.Hash, uint64)
+)
 
 // SetHead rewinds the local chain to a new head. Everything above the new head
 // will be deleted and the new one set.
-func (hc *HeaderChain) SetHead(head uint64, delFn DeleteCallback) {
-	height := uint64(0)
-
-	if hdr := hc.CurrentHeader(); hdr != nil {
-		height = hdr.Number.Uint64()
-	}
-	batch := hc.chainDb.NewBatch()
+func (hc *HeaderChain) SetHead(head uint64, updateFn UpdateHeadBlocksCallback, delFn DeleteBlockContentCallback) {
+	var (
+		parentHash common.Hash
+		batch      = hc.chainDb.NewBatch()
+	)
 	for hdr := hc.CurrentHeader(); hdr != nil && hdr.Number.Uint64() > head; hdr = hc.CurrentHeader() {
-		hash := hdr.Hash()
-		num := hdr.Number.Uint64()
+		hash, num := hdr.Hash(), hdr.Number.Uint64()
+
+		// Rewind block chain to new head.
+		parent := hc.GetHeader(hdr.ParentHash, num-1)
+		if parent == nil {
+			parent = hc.genesisHeader
+		}
+		parentHash = hdr.ParentHash
+		// Notably, since geth has the possibility for setting the head to a low
+		// height which is even lower than ancient head.
+		// In order to ensure that the head is always no higher than the data in
+		// the database(ancient store or active store), we need to update head
+		// first then remove the relative data from the database.
+		//
+		// Update head first(head fast block, head full block) before deleting the data.
+		if updateFn != nil {
+			updateFn(hc.chainDb, parent)
+		}
+		// Update head header then.
+		rawdb.WriteHeadHeaderHash(hc.chainDb, parentHash)
+
+		// Remove the relative data from the database.
 		if delFn != nil {
 			delFn(batch, hash, num)
 		}
+		// Rewind header chain to new head.
 		rawdb.DeleteHeader(batch, hash, num)
 		rawdb.DeleteTd(batch, hash, num)
+		rawdb.DeleteCanonicalHash(batch, num)
 
-		hc.currentHeader.Store(hc.GetHeader(hdr.ParentHash, hdr.Number.Uint64()-1))
-	}
-	// Roll back the canonical chain numbering
-	for i := height; i > head; i-- {
-		rawdb.DeleteCanonicalHash(batch, i)
+		hc.currentHeader.Store(parent)
+		hc.currentHeaderHash = parentHash
 	}
 	batch.Write()
 
@@ -487,13 +515,6 @@ func (hc *HeaderChain) SetHead(head uint64, delFn DeleteCallback) {
 	hc.headerCache.Purge()
 	hc.tdCache.Purge()
 	hc.numberCache.Purge()
-
-	if hc.CurrentHeader() == nil {
-		hc.currentHeader.Store(hc.genesisHeader)
-	}
-	hc.currentHeaderHash = hc.CurrentHeader().Hash()
-
-	rawdb.WriteHeadHeaderHash(hc.chainDb, hc.currentHeaderHash)
 }
 
 // SetGenesis sets a new genesis block header for the chain
diff --git a/core/rawdb/accessors_chain.go b/core/rawdb/accessors_chain.go
index cc0591a4c..fab7ca56c 100644
--- a/core/rawdb/accessors_chain.go
+++ b/core/rawdb/accessors_chain.go
@@ -31,7 +31,17 @@ import (
 
 // ReadCanonicalHash retrieves the hash assigned to a canonical block number.
 func ReadCanonicalHash(db ethdb.Reader, number uint64) common.Hash {
-	data, _ := db.Get(headerHashKey(number))
+	data, _ := db.Ancient(freezerHashTable, number)
+	if len(data) == 0 {
+		data, _ = db.Get(headerHashKey(number))
+		// In the background freezer is moving data from leveldb to flatten files.
+		// So during the first check for ancient db, the data is not yet in there,
+		// but when we reach into leveldb, the data was already moved. That would
+		// result in a not found error.
+		if len(data) == 0 {
+			data, _ = db.Ancient(freezerHashTable, number)
+		}
+	}
 	if len(data) == 0 {
 		return common.Hash{}
 	}
@@ -39,21 +49,38 @@ func ReadCanonicalHash(db ethdb.Reader, number uint64) common.Hash {
 }
 
 // WriteCanonicalHash stores the hash assigned to a canonical block number.
-func WriteCanonicalHash(db ethdb.Writer, hash common.Hash, number uint64) {
+func WriteCanonicalHash(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	if err := db.Put(headerHashKey(number), hash.Bytes()); err != nil {
 		log.Crit("Failed to store number to hash mapping", "err", err)
 	}
 }
 
 // DeleteCanonicalHash removes the number to hash canonical mapping.
-func DeleteCanonicalHash(db ethdb.Writer, number uint64) {
+func DeleteCanonicalHash(db ethdb.KeyValueWriter, number uint64) {
 	if err := db.Delete(headerHashKey(number)); err != nil {
 		log.Crit("Failed to delete number to hash mapping", "err", err)
 	}
 }
 
+// ReadAllHashes retrieves all the hashes assigned to blocks at a certain heights,
+// both canonical and reorged forks included.
+func ReadAllHashes(db ethdb.Iteratee, number uint64) []common.Hash {
+	prefix := headerKeyPrefix(number)
+
+	hashes := make([]common.Hash, 0, 1)
+	it := db.NewIteratorWithPrefix(prefix)
+	defer it.Release()
+
+	for it.Next() {
+		if key := it.Key(); len(key) == len(prefix)+32 {
+			hashes = append(hashes, common.BytesToHash(key[len(key)-32:]))
+		}
+	}
+	return hashes
+}
+
 // ReadHeaderNumber returns the header number assigned to a hash.
-func ReadHeaderNumber(db ethdb.Reader, hash common.Hash) *uint64 {
+func ReadHeaderNumber(db ethdb.KeyValueReader, hash common.Hash) *uint64 {
 	data, _ := db.Get(headerNumberKey(hash))
 	if len(data) != 8 {
 		return nil
@@ -62,8 +89,24 @@ func ReadHeaderNumber(db ethdb.Reader, hash common.Hash) *uint64 {
 	return &number
 }
 
+// WriteHeaderNumber stores the hash->number mapping.
+func WriteHeaderNumber(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
+	key := headerNumberKey(hash)
+	enc := encodeBlockNumber(number)
+	if err := db.Put(key, enc); err != nil {
+		log.Crit("Failed to store hash to number mapping", "err", err)
+	}
+}
+
+// DeleteHeaderNumber removes hash->number mapping.
+func DeleteHeaderNumber(db ethdb.KeyValueWriter, hash common.Hash) {
+	if err := db.Delete(headerNumberKey(hash)); err != nil {
+		log.Crit("Failed to delete hash to number mapping", "err", err)
+	}
+}
+
 // ReadHeadHeaderHash retrieves the hash of the current canonical head header.
-func ReadHeadHeaderHash(db ethdb.Reader) common.Hash {
+func ReadHeadHeaderHash(db ethdb.KeyValueReader) common.Hash {
 	data, _ := db.Get(headHeaderKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -72,14 +115,14 @@ func ReadHeadHeaderHash(db ethdb.Reader) common.Hash {
 }
 
 // WriteHeadHeaderHash stores the hash of the current canonical head header.
-func WriteHeadHeaderHash(db ethdb.Writer, hash common.Hash) {
+func WriteHeadHeaderHash(db ethdb.KeyValueWriter, hash common.Hash) {
 	if err := db.Put(headHeaderKey, hash.Bytes()); err != nil {
 		log.Crit("Failed to store last header's hash", "err", err)
 	}
 }
 
 // ReadHeadBlockHash retrieves the hash of the current canonical head block.
-func ReadHeadBlockHash(db ethdb.Reader) common.Hash {
+func ReadHeadBlockHash(db ethdb.KeyValueReader) common.Hash {
 	data, _ := db.Get(headBlockKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -88,14 +131,14 @@ func ReadHeadBlockHash(db ethdb.Reader) common.Hash {
 }
 
 // WriteHeadBlockHash stores the head block's hash.
-func WriteHeadBlockHash(db ethdb.Writer, hash common.Hash) {
+func WriteHeadBlockHash(db ethdb.KeyValueWriter, hash common.Hash) {
 	if err := db.Put(headBlockKey, hash.Bytes()); err != nil {
 		log.Crit("Failed to store last block's hash", "err", err)
 	}
 }
 
 // ReadHeadFastBlockHash retrieves the hash of the current fast-sync head block.
-func ReadHeadFastBlockHash(db ethdb.Reader) common.Hash {
+func ReadHeadFastBlockHash(db ethdb.KeyValueReader) common.Hash {
 	data, _ := db.Get(headFastBlockKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -104,7 +147,7 @@ func ReadHeadFastBlockHash(db ethdb.Reader) common.Hash {
 }
 
 // WriteHeadFastBlockHash stores the hash of the current fast-sync head block.
-func WriteHeadFastBlockHash(db ethdb.Writer, hash common.Hash) {
+func WriteHeadFastBlockHash(db ethdb.KeyValueWriter, hash common.Hash) {
 	if err := db.Put(headFastBlockKey, hash.Bytes()); err != nil {
 		log.Crit("Failed to store last fast block's hash", "err", err)
 	}
@@ -112,7 +155,7 @@ func WriteHeadFastBlockHash(db ethdb.Writer, hash common.Hash) {
 
 // ReadFastTrieProgress retrieves the number of tries nodes fast synced to allow
 // reporting correct numbers across restarts.
-func ReadFastTrieProgress(db ethdb.Reader) uint64 {
+func ReadFastTrieProgress(db ethdb.KeyValueReader) uint64 {
 	data, _ := db.Get(fastTrieProgressKey)
 	if len(data) == 0 {
 		return 0
@@ -122,7 +165,7 @@ func ReadFastTrieProgress(db ethdb.Reader) uint64 {
 
 // WriteFastTrieProgress stores the fast sync trie process counter to support
 // retrieving it across restarts.
-func WriteFastTrieProgress(db ethdb.Writer, count uint64) {
+func WriteFastTrieProgress(db ethdb.KeyValueWriter, count uint64) {
 	if err := db.Put(fastTrieProgressKey, new(big.Int).SetUint64(count).Bytes()); err != nil {
 		log.Crit("Failed to store fast sync trie progress", "err", err)
 	}
@@ -130,12 +173,25 @@ func WriteFastTrieProgress(db ethdb.Writer, count uint64) {
 
 // ReadHeaderRLP retrieves a block header in its raw RLP database encoding.
 func ReadHeaderRLP(db ethdb.Reader, hash common.Hash, number uint64) rlp.RawValue {
-	data, _ := db.Get(headerKey(number, hash))
+	data, _ := db.Ancient(freezerHeaderTable, number)
+	if len(data) == 0 {
+		data, _ = db.Get(headerKey(number, hash))
+		// In the background freezer is moving data from leveldb to flatten files.
+		// So during the first check for ancient db, the data is not yet in there,
+		// but when we reach into leveldb, the data was already moved. That would
+		// result in a not found error.
+		if len(data) == 0 {
+			data, _ = db.Ancient(freezerHeaderTable, number)
+		}
+	}
 	return data
 }
 
 // HasHeader verifies the existence of a block header corresponding to the hash.
 func HasHeader(db ethdb.Reader, hash common.Hash, number uint64) bool {
+	if has, err := db.Ancient(freezerHashTable, number); err == nil && common.BytesToHash(has) == hash {
+		return true
+	}
 	if has, err := db.Has(headerKey(number, hash)); !has || err != nil {
 		return false
 	}
@@ -158,30 +214,27 @@ func ReadHeader(db ethdb.Reader, hash common.Hash, number uint64) *types.Header
 
 // WriteHeader stores a block header into the database and also stores the hash-
 // to-number mapping.
-func WriteHeader(db ethdb.Writer, header *types.Header) {
-	// Write the hash -> number mapping
+func WriteHeader(db ethdb.KeyValueWriter, header *types.Header) {
 	var (
-		hash    = header.Hash()
-		number  = header.Number.Uint64()
-		encoded = encodeBlockNumber(number)
+		hash   = header.Hash()
+		number = header.Number.Uint64()
 	)
-	key := headerNumberKey(hash)
-	if err := db.Put(key, encoded); err != nil {
-		log.Crit("Failed to store hash to number mapping", "err", err)
-	}
+	// Write the hash -> number mapping
+	WriteHeaderNumber(db, hash, number)
+
 	// Write the encoded header
 	data, err := rlp.EncodeToBytes(header)
 	if err != nil {
 		log.Crit("Failed to RLP encode header", "err", err)
 	}
-	key = headerKey(number, hash)
+	key := headerKey(number, hash)
 	if err := db.Put(key, data); err != nil {
 		log.Crit("Failed to store header", "err", err)
 	}
 }
 
 // DeleteHeader removes all block header data associated with a hash.
-func DeleteHeader(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteHeader(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	deleteHeaderWithoutNumber(db, hash, number)
 	if err := db.Delete(headerNumberKey(hash)); err != nil {
 		log.Crit("Failed to delete hash to number mapping", "err", err)
@@ -190,7 +243,7 @@ func DeleteHeader(db ethdb.Writer, hash common.Hash, number uint64) {
 
 // deleteHeaderWithoutNumber removes only the block header but does not remove
 // the hash to number mapping.
-func deleteHeaderWithoutNumber(db ethdb.Writer, hash common.Hash, number uint64) {
+func deleteHeaderWithoutNumber(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	if err := db.Delete(headerKey(number, hash)); err != nil {
 		log.Crit("Failed to delete header", "err", err)
 	}
@@ -198,12 +251,22 @@ func deleteHeaderWithoutNumber(db ethdb.Writer, hash common.Hash, number uint64)
 
 // ReadBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
 func ReadBodyRLP(db ethdb.Reader, hash common.Hash, number uint64) rlp.RawValue {
-	data, _ := db.Get(blockBodyKey(number, hash))
+	data, _ := db.Ancient(freezerBodiesTable, number)
+	if len(data) == 0 {
+		data, _ = db.Get(blockBodyKey(number, hash))
+		// In the background freezer is moving data from leveldb to flatten files.
+		// So during the first check for ancient db, the data is not yet in there,
+		// but when we reach into leveldb, the data was already moved. That would
+		// result in a not found error.
+		if len(data) == 0 {
+			data, _ = db.Ancient(freezerBodiesTable, number)
+		}
+	}
 	return data
 }
 
 // WriteBodyRLP stores an RLP encoded block body into the database.
-func WriteBodyRLP(db ethdb.Writer, hash common.Hash, number uint64, rlp rlp.RawValue) {
+func WriteBodyRLP(db ethdb.KeyValueWriter, hash common.Hash, number uint64, rlp rlp.RawValue) {
 	if err := db.Put(blockBodyKey(number, hash), rlp); err != nil {
 		log.Crit("Failed to store block body", "err", err)
 	}
@@ -211,6 +274,9 @@ func WriteBodyRLP(db ethdb.Writer, hash common.Hash, number uint64, rlp rlp.RawV
 
 // HasBody verifies the existence of a block body corresponding to the hash.
 func HasBody(db ethdb.Reader, hash common.Hash, number uint64) bool {
+	if has, err := db.Ancient(freezerHashTable, number); err == nil && common.BytesToHash(has) == hash {
+		return true
+	}
 	if has, err := db.Has(blockBodyKey(number, hash)); !has || err != nil {
 		return false
 	}
@@ -232,7 +298,7 @@ func ReadBody(db ethdb.Reader, hash common.Hash, number uint64) *types.Body {
 }
 
 // WriteBody stores a block body into the database.
-func WriteBody(db ethdb.Writer, hash common.Hash, number uint64, body *types.Body) {
+func WriteBody(db ethdb.KeyValueWriter, hash common.Hash, number uint64, body *types.Body) {
 	data, err := rlp.EncodeToBytes(body)
 	if err != nil {
 		log.Crit("Failed to RLP encode body", "err", err)
@@ -241,7 +307,7 @@ func WriteBody(db ethdb.Writer, hash common.Hash, number uint64, body *types.Bod
 }
 
 // DeleteBody removes all block body data associated with a hash.
-func DeleteBody(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteBody(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	if err := db.Delete(blockBodyKey(number, hash)); err != nil {
 		log.Crit("Failed to delete block body", "err", err)
 	}
@@ -249,7 +315,17 @@ func DeleteBody(db ethdb.Writer, hash common.Hash, number uint64) {
 
 // ReadTdRLP retrieves a block's total difficulty corresponding to the hash in RLP encoding.
 func ReadTdRLP(db ethdb.Reader, hash common.Hash, number uint64) rlp.RawValue {
-	data, _ := db.Get(headerTDKey(number, hash))
+	data, _ := db.Ancient(freezerDifficultyTable, number)
+	if len(data) == 0 {
+		data, _ = db.Get(headerTDKey(number, hash))
+		// In the background freezer is moving data from leveldb to flatten files.
+		// So during the first check for ancient db, the data is not yet in there,
+		// but when we reach into leveldb, the data was already moved. That would
+		// result in a not found error.
+		if len(data) == 0 {
+			data, _ = db.Ancient(freezerDifficultyTable, number)
+		}
+	}
 	return data
 }
 
@@ -268,7 +344,7 @@ func ReadTd(db ethdb.Reader, hash common.Hash, number uint64) *big.Int {
 }
 
 // WriteTd stores the total difficulty of a block into the database.
-func WriteTd(db ethdb.Writer, hash common.Hash, number uint64, td *big.Int) {
+func WriteTd(db ethdb.KeyValueWriter, hash common.Hash, number uint64, td *big.Int) {
 	data, err := rlp.EncodeToBytes(td)
 	if err != nil {
 		log.Crit("Failed to RLP encode block total difficulty", "err", err)
@@ -279,7 +355,7 @@ func WriteTd(db ethdb.Writer, hash common.Hash, number uint64, td *big.Int) {
 }
 
 // DeleteTd removes all block total difficulty data associated with a hash.
-func DeleteTd(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteTd(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	if err := db.Delete(headerTDKey(number, hash)); err != nil {
 		log.Crit("Failed to delete block total difficulty", "err", err)
 	}
@@ -288,6 +364,9 @@ func DeleteTd(db ethdb.Writer, hash common.Hash, number uint64) {
 // HasReceipts verifies the existence of all the transaction receipts belonging
 // to a block.
 func HasReceipts(db ethdb.Reader, hash common.Hash, number uint64) bool {
+	if has, err := db.Ancient(freezerHashTable, number); err == nil && common.BytesToHash(has) == hash {
+		return true
+	}
 	if has, err := db.Has(blockReceiptsKey(number, hash)); !has || err != nil {
 		return false
 	}
@@ -296,7 +375,17 @@ func HasReceipts(db ethdb.Reader, hash common.Hash, number uint64) bool {
 
 // ReadReceiptsRLP retrieves all the transaction receipts belonging to a block in RLP encoding.
 func ReadReceiptsRLP(db ethdb.Reader, hash common.Hash, number uint64) rlp.RawValue {
-	data, _ := db.Get(blockReceiptsKey(number, hash))
+	data, _ := db.Ancient(freezerReceiptTable, number)
+	if len(data) == 0 {
+		data, _ = db.Get(blockReceiptsKey(number, hash))
+		// In the background freezer is moving data from leveldb to flatten files.
+		// So during the first check for ancient db, the data is not yet in there,
+		// but when we reach into leveldb, the data was already moved. That would
+		// result in a not found error.
+		if len(data) == 0 {
+			data, _ = db.Ancient(freezerReceiptTable, number)
+		}
+	}
 	return data
 }
 
@@ -348,7 +437,7 @@ func ReadReceipts(db ethdb.Reader, hash common.Hash, number uint64, config *para
 }
 
 // WriteReceipts stores all the transaction receipts belonging to a block.
-func WriteReceipts(db ethdb.Writer, hash common.Hash, number uint64, receipts types.Receipts) {
+func WriteReceipts(db ethdb.KeyValueWriter, hash common.Hash, number uint64, receipts types.Receipts) {
 	// Convert the receipts into their storage form and serialize them
 	storageReceipts := make([]*types.ReceiptForStorage, len(receipts))
 	for i, receipt := range receipts {
@@ -365,7 +454,7 @@ func WriteReceipts(db ethdb.Writer, hash common.Hash, number uint64, receipts ty
 }
 
 // DeleteReceipts removes all receipt data associated with a block hash.
-func DeleteReceipts(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteReceipts(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	if err := db.Delete(blockReceiptsKey(number, hash)); err != nil {
 		log.Crit("Failed to delete block receipts", "err", err)
 	}
@@ -390,22 +479,53 @@ func ReadBlock(db ethdb.Reader, hash common.Hash, number uint64) *types.Block {
 }
 
 // WriteBlock serializes a block into the database, header and body separately.
-func WriteBlock(db ethdb.Writer, block *types.Block) {
+func WriteBlock(db ethdb.KeyValueWriter, block *types.Block) {
 	WriteBody(db, block.Hash(), block.NumberU64(), block.Body())
 	WriteHeader(db, block.Header())
 }
 
+// WriteAncientBlock writes entire block data into ancient store and returns the total written size.
+func WriteAncientBlock(db ethdb.AncientWriter, block *types.Block, receipts types.Receipts, td *big.Int) int {
+	// Encode all block components to RLP format.
+	headerBlob, err := rlp.EncodeToBytes(block.Header())
+	if err != nil {
+		log.Crit("Failed to RLP encode block header", "err", err)
+	}
+	bodyBlob, err := rlp.EncodeToBytes(block.Body())
+	if err != nil {
+		log.Crit("Failed to RLP encode body", "err", err)
+	}
+	storageReceipts := make([]*types.ReceiptForStorage, len(receipts))
+	for i, receipt := range receipts {
+		storageReceipts[i] = (*types.ReceiptForStorage)(receipt)
+	}
+	receiptBlob, err := rlp.EncodeToBytes(storageReceipts)
+	if err != nil {
+		log.Crit("Failed to RLP encode block receipts", "err", err)
+	}
+	tdBlob, err := rlp.EncodeToBytes(td)
+	if err != nil {
+		log.Crit("Failed to RLP encode block total difficulty", "err", err)
+	}
+	// Write all blob to flatten files.
+	err = db.AppendAncient(block.NumberU64(), block.Hash().Bytes(), headerBlob, bodyBlob, receiptBlob, tdBlob)
+	if err != nil {
+		log.Crit("Failed to write block data to ancient store", "err", err)
+	}
+	return len(headerBlob) + len(bodyBlob) + len(receiptBlob) + len(tdBlob) + common.HashLength
+}
+
 // DeleteBlock removes all block data associated with a hash.
-func DeleteBlock(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteBlock(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	DeleteReceipts(db, hash, number)
 	DeleteHeader(db, hash, number)
 	DeleteBody(db, hash, number)
 	DeleteTd(db, hash, number)
 }
 
-// deleteBlockWithoutNumber removes all block data associated with a hash, except
+// DeleteBlockWithoutNumber removes all block data associated with a hash, except
 // the hash to number mapping.
-func deleteBlockWithoutNumber(db ethdb.Writer, hash common.Hash, number uint64) {
+func DeleteBlockWithoutNumber(db ethdb.KeyValueWriter, hash common.Hash, number uint64) {
 	DeleteReceipts(db, hash, number)
 	deleteHeaderWithoutNumber(db, hash, number)
 	DeleteBody(db, hash, number)
diff --git a/core/rawdb/accessors_indexes.go b/core/rawdb/accessors_indexes.go
index 423145a76..ed1f1bca6 100644
--- a/core/rawdb/accessors_indexes.go
+++ b/core/rawdb/accessors_indexes.go
@@ -54,7 +54,7 @@ func ReadTxLookupEntry(db ethdb.Reader, hash common.Hash) *uint64 {
 
 // WriteTxLookupEntries stores a positional metadata for every transaction from
 // a block, enabling hash based transaction and receipt lookups.
-func WriteTxLookupEntries(db ethdb.Writer, block *types.Block) {
+func WriteTxLookupEntries(db ethdb.KeyValueWriter, block *types.Block) {
 	for _, tx := range block.Transactions() {
 		if err := db.Put(txLookupKey(tx.Hash()), block.Number().Bytes()); err != nil {
 			log.Crit("Failed to store transaction lookup entry", "err", err)
@@ -63,7 +63,7 @@ func WriteTxLookupEntries(db ethdb.Writer, block *types.Block) {
 }
 
 // DeleteTxLookupEntry removes all transaction data associated with a hash.
-func DeleteTxLookupEntry(db ethdb.Writer, hash common.Hash) {
+func DeleteTxLookupEntry(db ethdb.KeyValueWriter, hash common.Hash) {
 	db.Delete(txLookupKey(hash))
 }
 
@@ -117,13 +117,13 @@ func ReadReceipt(db ethdb.Reader, hash common.Hash, config *params.ChainConfig)
 
 // ReadBloomBits retrieves the compressed bloom bit vector belonging to the given
 // section and bit index from the.
-func ReadBloomBits(db ethdb.Reader, bit uint, section uint64, head common.Hash) ([]byte, error) {
+func ReadBloomBits(db ethdb.KeyValueReader, bit uint, section uint64, head common.Hash) ([]byte, error) {
 	return db.Get(bloomBitsKey(bit, section, head))
 }
 
 // WriteBloomBits stores the compressed bloom bits vector belonging to the given
 // section and bit index.
-func WriteBloomBits(db ethdb.Writer, bit uint, section uint64, head common.Hash, bits []byte) {
+func WriteBloomBits(db ethdb.KeyValueWriter, bit uint, section uint64, head common.Hash, bits []byte) {
 	if err := db.Put(bloomBitsKey(bit, section, head), bits); err != nil {
 		log.Crit("Failed to store bloom bits", "err", err)
 	}
diff --git a/core/rawdb/accessors_metadata.go b/core/rawdb/accessors_metadata.go
index 1361b0d73..f8d09fbdd 100644
--- a/core/rawdb/accessors_metadata.go
+++ b/core/rawdb/accessors_metadata.go
@@ -27,7 +27,7 @@ import (
 )
 
 // ReadDatabaseVersion retrieves the version number of the database.
-func ReadDatabaseVersion(db ethdb.Reader) *uint64 {
+func ReadDatabaseVersion(db ethdb.KeyValueReader) *uint64 {
 	var version uint64
 
 	enc, _ := db.Get(databaseVerisionKey)
@@ -42,7 +42,7 @@ func ReadDatabaseVersion(db ethdb.Reader) *uint64 {
 }
 
 // WriteDatabaseVersion stores the version number of the database
-func WriteDatabaseVersion(db ethdb.Writer, version uint64) {
+func WriteDatabaseVersion(db ethdb.KeyValueWriter, version uint64) {
 	enc, err := rlp.EncodeToBytes(version)
 	if err != nil {
 		log.Crit("Failed to encode database version", "err", err)
@@ -53,7 +53,7 @@ func WriteDatabaseVersion(db ethdb.Writer, version uint64) {
 }
 
 // ReadChainConfig retrieves the consensus settings based on the given genesis hash.
-func ReadChainConfig(db ethdb.Reader, hash common.Hash) *params.ChainConfig {
+func ReadChainConfig(db ethdb.KeyValueReader, hash common.Hash) *params.ChainConfig {
 	data, _ := db.Get(configKey(hash))
 	if len(data) == 0 {
 		return nil
@@ -67,7 +67,7 @@ func ReadChainConfig(db ethdb.Reader, hash common.Hash) *params.ChainConfig {
 }
 
 // WriteChainConfig writes the chain config settings to the database.
-func WriteChainConfig(db ethdb.Writer, hash common.Hash, cfg *params.ChainConfig) {
+func WriteChainConfig(db ethdb.KeyValueWriter, hash common.Hash, cfg *params.ChainConfig) {
 	if cfg == nil {
 		return
 	}
@@ -81,13 +81,13 @@ func WriteChainConfig(db ethdb.Writer, hash common.Hash, cfg *params.ChainConfig
 }
 
 // ReadPreimage retrieves a single preimage of the provided hash.
-func ReadPreimage(db ethdb.Reader, hash common.Hash) []byte {
+func ReadPreimage(db ethdb.KeyValueReader, hash common.Hash) []byte {
 	data, _ := db.Get(preimageKey(hash))
 	return data
 }
 
 // WritePreimages writes the provided set of preimages to the database.
-func WritePreimages(db ethdb.Writer, preimages map[common.Hash][]byte) {
+func WritePreimages(db ethdb.KeyValueWriter, preimages map[common.Hash][]byte) {
 	for hash, preimage := range preimages {
 		if err := db.Put(preimageKey(hash), preimage); err != nil {
 			log.Crit("Failed to store trie preimage", "err", err)
diff --git a/core/rawdb/database.go b/core/rawdb/database.go
index b4c5dea70..353b7dce6 100644
--- a/core/rawdb/database.go
+++ b/core/rawdb/database.go
@@ -17,15 +17,168 @@
 package rawdb
 
 import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/ethdb/leveldb"
 	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/olekukonko/tablewriter"
 )
 
+// freezerdb is a database wrapper that enabled freezer data retrievals.
+type freezerdb struct {
+	ethdb.KeyValueStore
+	ethdb.AncientStore
+}
+
+// Close implements io.Closer, closing both the fast key-value store as well as
+// the slow ancient tables.
+func (frdb *freezerdb) Close() error {
+	var errs []error
+	if err := frdb.KeyValueStore.Close(); err != nil {
+		errs = append(errs, err)
+	}
+	if err := frdb.AncientStore.Close(); err != nil {
+		errs = append(errs, err)
+	}
+	if len(errs) != 0 {
+		return fmt.Errorf("%v", errs)
+	}
+	return nil
+}
+
+// nofreezedb is a database wrapper that disables freezer data retrievals.
+type nofreezedb struct {
+	ethdb.KeyValueStore
+}
+
+// HasAncient returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) HasAncient(kind string, number uint64) (bool, error) {
+	return false, errNotSupported
+}
+
+// Ancient returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) Ancient(kind string, number uint64) ([]byte, error) {
+	return nil, errNotSupported
+}
+
+// Ancients returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) Ancients() (uint64, error) {
+	return 0, errNotSupported
+}
+
+// AncientSize returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) AncientSize(kind string) (uint64, error) {
+	return 0, errNotSupported
+}
+
+// AppendAncient returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) AppendAncient(number uint64, hash, header, body, receipts, td []byte) error {
+	return errNotSupported
+}
+
+// TruncateAncients returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) TruncateAncients(items uint64) error {
+	return errNotSupported
+}
+
+// Sync returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) Sync() error {
+	return errNotSupported
+}
+
 // NewDatabase creates a high level database on top of a given key-value data
 // store without a freezer moving immutable chain segments into cold storage.
 func NewDatabase(db ethdb.KeyValueStore) ethdb.Database {
-	return db
+	return &nofreezedb{
+		KeyValueStore: db,
+	}
+}
+
+// NewDatabaseWithFreezer creates a high level database on top of a given key-
+// value data store with a freezer moving immutable chain segments into cold
+// storage.
+func NewDatabaseWithFreezer(db ethdb.KeyValueStore, freezer string, namespace string) (ethdb.Database, error) {
+	// Create the idle freezer instance
+	frdb, err := newFreezer(freezer, namespace)
+	if err != nil {
+		return nil, err
+	}
+	// Since the freezer can be stored separately from the user's key-value database,
+	// there's a fairly high probability that the user requests invalid combinations
+	// of the freezer and database. Ensure that we don't shoot ourselves in the foot
+	// by serving up conflicting data, leading to both datastores getting corrupted.
+	//
+	//   - If both the freezer and key-value store is empty (no genesis), we just
+	//     initialized a new empty freezer, so everything's fine.
+	//   - If the key-value store is empty, but the freezer is not, we need to make
+	//     sure the user's genesis matches the freezer. That will be checked in the
+	//     blockchain, since we don't have the genesis block here (nor should we at
+	//     this point care, the key-value/freezer combo is valid).
+	//   - If neither the key-value store nor the freezer is empty, cross validate
+	//     the genesis hashes to make sure they are compatible. If they are, also
+	//     ensure that there's no gap between the freezer and sunsequently leveldb.
+	//   - If the key-value store is not empty, but the freezer is we might just be
+	//     upgrading to the freezer release, or we might have had a small chain and
+	//     not frozen anything yet. Ensure that no blocks are missing yet from the
+	//     key-value store, since that would mean we already had an old freezer.
+
+	// If the genesis hash is empty, we have a new key-value store, so nothing to
+	// validate in this method. If, however, the genesis hash is not nil, compare
+	// it to the freezer content.
+	if kvgenesis, _ := db.Get(headerHashKey(0)); len(kvgenesis) > 0 {
+		if frozen, _ := frdb.Ancients(); frozen > 0 {
+			// If the freezer already contains something, ensure that the genesis blocks
+			// match, otherwise we might mix up freezers across chains and destroy both
+			// the freezer and the key-value store.
+			if frgenesis, _ := frdb.Ancient(freezerHashTable, 0); !bytes.Equal(kvgenesis, frgenesis) {
+				return nil, fmt.Errorf("genesis mismatch: %#x (leveldb) != %#x (ancients)", kvgenesis, frgenesis)
+			}
+			// Key-value store and freezer belong to the same network. Ensure that they
+			// are contiguous, otherwise we might end up with a non-functional freezer.
+			if kvhash, _ := db.Get(headerHashKey(frozen)); len(kvhash) == 0 {
+				// Subsequent header after the freezer limit is missing from the database.
+				// Reject startup is the database has a more recent head.
+				if *ReadHeaderNumber(db, ReadHeadHeaderHash(db)) > frozen-1 {
+					return nil, fmt.Errorf("gap (#%d) in the chain between ancients and leveldb", frozen)
+				}
+				// Database contains only older data than the freezer, this happens if the
+				// state was wiped and reinited from an existing freezer.
+			} else {
+				// Key-value store continues where the freezer left off, all is fine. We might
+				// have duplicate blocks (crash after freezer write but before kay-value store
+				// deletion, but that's fine).
+			}
+		} else {
+			// If the freezer is empty, ensure nothing was moved yet from the key-value
+			// store, otherwise we'll end up missing data. We check block #1 to decide
+			// if we froze anything previously or not, but do take care of databases with
+			// only the genesis block.
+			if ReadHeadHeaderHash(db) != common.BytesToHash(kvgenesis) {
+				// Key-value store contains more data than the genesis block, make sure we
+				// didn't freeze anything yet.
+				if kvblob, _ := db.Get(headerHashKey(1)); len(kvblob) == 0 {
+					return nil, errors.New("ancient chain segments already extracted, please set --datadir.ancient to the correct path")
+				}
+				// Block #1 is still in the database, we're allowed to init a new feezer
+			} else {
+				// The head header is still the genesis, we're allowed to init a new feezer
+			}
+		}
+	}
+	// Freezer is consistent with the key-value database, permit combining the two
+	go frdb.freeze(db)
+
+	return &freezerdb{
+		KeyValueStore: db,
+		AncientStore:  frdb,
+	}, nil
 }
 
 // NewMemoryDatabase creates an ephemeral in-memory key-value database without a
@@ -34,9 +187,9 @@ func NewMemoryDatabase() ethdb.Database {
 	return NewDatabase(memorydb.New())
 }
 
-// NewMemoryDatabaseWithCap creates an ephemeral in-memory key-value database with
-// an initial starting capacity, but without a freezer moving immutable chain
-// segments into cold storage.
+// NewMemoryDatabaseWithCap creates an ephemeral in-memory key-value database
+// with an initial starting capacity, but without a freezer moving immutable
+// chain segments into cold storage.
 func NewMemoryDatabaseWithCap(size int) ethdb.Database {
 	return NewDatabase(memorydb.NewWithCap(size))
 }
@@ -50,3 +203,153 @@ func NewLevelDBDatabase(file string, cache int, handles int, namespace string) (
 	}
 	return NewDatabase(db), nil
 }
+
+// NewLevelDBDatabaseWithFreezer creates a persistent key-value database with a
+// freezer moving immutable chain segments into cold storage.
+func NewLevelDBDatabaseWithFreezer(file string, cache int, handles int, freezer string, namespace string) (ethdb.Database, error) {
+	kvdb, err := leveldb.New(file, cache, handles, namespace)
+	if err != nil {
+		return nil, err
+	}
+	frdb, err := NewDatabaseWithFreezer(kvdb, freezer, namespace)
+	if err != nil {
+		kvdb.Close()
+		return nil, err
+	}
+	return frdb, nil
+}
+
+// InspectDatabase traverses the entire database and checks the size
+// of all different categories of data.
+func InspectDatabase(db ethdb.Database) error {
+	it := db.NewIterator()
+	defer it.Release()
+
+	var (
+		count  int64
+		start  = time.Now()
+		logged = time.Now()
+
+		// Key-value store statistics
+		total           common.StorageSize
+		headerSize      common.StorageSize
+		bodySize        common.StorageSize
+		receiptSize     common.StorageSize
+		tdSize          common.StorageSize
+		numHashPairing  common.StorageSize
+		hashNumPairing  common.StorageSize
+		trieSize        common.StorageSize
+		txlookupSize    common.StorageSize
+		preimageSize    common.StorageSize
+		bloomBitsSize   common.StorageSize
+		cliqueSnapsSize common.StorageSize
+
+		// Ancient store statistics
+		ancientHeaders  common.StorageSize
+		ancientBodies   common.StorageSize
+		ancientReceipts common.StorageSize
+		ancientHashes   common.StorageSize
+		ancientTds      common.StorageSize
+
+		// Les statistic
+		chtTrieNodes   common.StorageSize
+		bloomTrieNodes common.StorageSize
+
+		// Meta- and unaccounted data
+		metadata    common.StorageSize
+		unaccounted common.StorageSize
+	)
+	// Inspect key-value database first.
+	for it.Next() {
+		var (
+			key  = it.Key()
+			size = common.StorageSize(len(key) + len(it.Value()))
+		)
+		total += size
+		switch {
+		case bytes.HasPrefix(key, headerPrefix) && bytes.HasSuffix(key, headerTDSuffix):
+			tdSize += size
+		case bytes.HasPrefix(key, headerPrefix) && bytes.HasSuffix(key, headerHashSuffix):
+			numHashPairing += size
+		case bytes.HasPrefix(key, headerPrefix) && len(key) == (len(headerPrefix)+8+common.HashLength):
+			headerSize += size
+		case bytes.HasPrefix(key, headerNumberPrefix) && len(key) == (len(headerNumberPrefix)+common.HashLength):
+			hashNumPairing += size
+		case bytes.HasPrefix(key, blockBodyPrefix) && len(key) == (len(blockBodyPrefix)+8+common.HashLength):
+			bodySize += size
+		case bytes.HasPrefix(key, blockReceiptsPrefix) && len(key) == (len(blockReceiptsPrefix)+8+common.HashLength):
+			receiptSize += size
+		case bytes.HasPrefix(key, txLookupPrefix) && len(key) == (len(txLookupPrefix)+common.HashLength):
+			txlookupSize += size
+		case bytes.HasPrefix(key, preimagePrefix) && len(key) == (len(preimagePrefix)+common.HashLength):
+			preimageSize += size
+		case bytes.HasPrefix(key, bloomBitsPrefix) && len(key) == (len(bloomBitsPrefix)+10+common.HashLength):
+			bloomBitsSize += size
+		case bytes.HasPrefix(key, []byte("clique-")) && len(key) == 7+common.HashLength:
+			cliqueSnapsSize += size
+		case bytes.HasPrefix(key, []byte("cht-")) && len(key) == 4+common.HashLength:
+			chtTrieNodes += size
+		case bytes.HasPrefix(key, []byte("blt-")) && len(key) == 4+common.HashLength:
+			bloomTrieNodes += size
+		case len(key) == common.HashLength:
+			trieSize += size
+		default:
+			var accounted bool
+			for _, meta := range [][]byte{databaseVerisionKey, headHeaderKey, headBlockKey, headFastBlockKey, fastTrieProgressKey} {
+				if bytes.Equal(key, meta) {
+					metadata += size
+					accounted = true
+					break
+				}
+			}
+			if !accounted {
+				unaccounted += size
+			}
+		}
+		count += 1
+		if count%1000 == 0 && time.Since(logged) > 8*time.Second {
+			log.Info("Inspecting database", "count", count, "elapsed", common.PrettyDuration(time.Since(start)))
+			logged = time.Now()
+		}
+	}
+	// Inspect append-only file store then.
+	ancients := []*common.StorageSize{&ancientHeaders, &ancientBodies, &ancientReceipts, &ancientHashes, &ancientTds}
+	for i, category := range []string{freezerHeaderTable, freezerBodiesTable, freezerReceiptTable, freezerHashTable, freezerDifficultyTable} {
+		if size, err := db.AncientSize(category); err == nil {
+			*ancients[i] += common.StorageSize(size)
+			total += common.StorageSize(size)
+		}
+	}
+	// Display the database statistic.
+	stats := [][]string{
+		{"Key-Value store", "Headers", headerSize.String()},
+		{"Key-Value store", "Bodies", bodySize.String()},
+		{"Key-Value store", "Receipts", receiptSize.String()},
+		{"Key-Value store", "Difficulties", tdSize.String()},
+		{"Key-Value store", "Block number->hash", numHashPairing.String()},
+		{"Key-Value store", "Block hash->number", hashNumPairing.String()},
+		{"Key-Value store", "Transaction index", txlookupSize.String()},
+		{"Key-Value store", "Bloombit index", bloomBitsSize.String()},
+		{"Key-Value store", "Trie nodes", trieSize.String()},
+		{"Key-Value store", "Trie preimages", preimageSize.String()},
+		{"Key-Value store", "Clique snapshots", cliqueSnapsSize.String()},
+		{"Key-Value store", "Singleton metadata", metadata.String()},
+		{"Ancient store", "Headers", ancientHeaders.String()},
+		{"Ancient store", "Bodies", ancientBodies.String()},
+		{"Ancient store", "Receipts", ancientReceipts.String()},
+		{"Ancient store", "Difficulties", ancientTds.String()},
+		{"Ancient store", "Block number->hash", ancientHashes.String()},
+		{"Light client", "CHT trie nodes", chtTrieNodes.String()},
+		{"Light client", "Bloom trie nodes", bloomTrieNodes.String()},
+	}
+	table := tablewriter.NewWriter(os.Stdout)
+	table.SetHeader([]string{"Database", "Category", "Size"})
+	table.SetFooter([]string{"", "Total", total.String()})
+	table.AppendBulk(stats)
+	table.Render()
+
+	if unaccounted > 0 {
+		log.Error("Database contains unaccounted data", "size", unaccounted)
+	}
+	return nil
+}
diff --git a/core/rawdb/freezer.go b/core/rawdb/freezer.go
new file mode 100644
index 000000000..67ed87d66
--- /dev/null
+++ b/core/rawdb/freezer.go
@@ -0,0 +1,382 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"os"
+	"path/filepath"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/prometheus/tsdb/fileutil"
+)
+
+var (
+	// errUnknownTable is returned if the user attempts to read from a table that is
+	// not tracked by the freezer.
+	errUnknownTable = errors.New("unknown table")
+
+	// errOutOrderInsertion is returned if the user attempts to inject out-of-order
+	// binary blobs into the freezer.
+	errOutOrderInsertion = errors.New("the append operation is out-order")
+
+	// errSymlinkDatadir is returned if the ancient directory specified by user
+	// is a symbolic link.
+	errSymlinkDatadir = errors.New("symbolic link datadir is not supported")
+)
+
+const (
+	// freezerRecheckInterval is the frequency to check the key-value database for
+	// chain progression that might permit new blocks to be frozen into immutable
+	// storage.
+	freezerRecheckInterval = time.Minute
+
+	// freezerBatchLimit is the maximum number of blocks to freeze in one batch
+	// before doing an fsync and deleting it from the key-value store.
+	freezerBatchLimit = 30000
+)
+
+// freezer is an memory mapped append-only database to store immutable chain data
+// into flat files:
+//
+// - The append only nature ensures that disk writes are minimized.
+// - The memory mapping ensures we can max out system memory for caching without
+//   reserving it for go-ethereum. This would also reduce the memory requirements
+//   of Geth, and thus also GC overhead.
+type freezer struct {
+	tables       map[string]*freezerTable // Data tables for storing everything
+	frozen       uint64                   // Number of blocks already frozen
+	instanceLock fileutil.Releaser        // File-system lock to prevent double opens
+}
+
+// newFreezer creates a chain freezer that moves ancient chain data into
+// append-only flat file containers.
+func newFreezer(datadir string, namespace string) (*freezer, error) {
+	// Create the initial freezer object
+	var (
+		readMeter  = metrics.NewRegisteredMeter(namespace+"ancient/read", nil)
+		writeMeter = metrics.NewRegisteredMeter(namespace+"ancient/write", nil)
+	)
+	// Ensure the datadir is not a symbolic link if it exists.
+	if info, err := os.Lstat(datadir); !os.IsNotExist(err) {
+		if info.Mode()&os.ModeSymlink != 0 {
+			log.Warn("Symbolic link ancient database is not supported", "path", datadir)
+			return nil, errSymlinkDatadir
+		}
+	}
+	// Leveldb uses LOCK as the filelock filename. To prevent the
+	// name collision, we use FLOCK as the lock name.
+	lock, _, err := fileutil.Flock(filepath.Join(datadir, "FLOCK"))
+	if err != nil {
+		return nil, err
+	}
+	// Open all the supported data tables
+	freezer := &freezer{
+		tables:       make(map[string]*freezerTable),
+		instanceLock: lock,
+	}
+	for name, disableSnappy := range freezerNoSnappy {
+		table, err := newTable(datadir, name, readMeter, writeMeter, disableSnappy)
+		if err != nil {
+			for _, table := range freezer.tables {
+				table.Close()
+			}
+			lock.Release()
+			return nil, err
+		}
+		freezer.tables[name] = table
+	}
+	if err := freezer.repair(); err != nil {
+		for _, table := range freezer.tables {
+			table.Close()
+		}
+		lock.Release()
+		return nil, err
+	}
+	log.Info("Opened ancient database", "database", datadir)
+	return freezer, nil
+}
+
+// Close terminates the chain freezer, unmapping all the data files.
+func (f *freezer) Close() error {
+	var errs []error
+	for _, table := range f.tables {
+		if err := table.Close(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	if err := f.instanceLock.Release(); err != nil {
+		errs = append(errs, err)
+	}
+	if errs != nil {
+		return fmt.Errorf("%v", errs)
+	}
+	return nil
+}
+
+// HasAncient returns an indicator whether the specified ancient data exists
+// in the freezer.
+func (f *freezer) HasAncient(kind string, number uint64) (bool, error) {
+	if table := f.tables[kind]; table != nil {
+		return table.has(number), nil
+	}
+	return false, nil
+}
+
+// Ancient retrieves an ancient binary blob from the append-only immutable files.
+func (f *freezer) Ancient(kind string, number uint64) ([]byte, error) {
+	if table := f.tables[kind]; table != nil {
+		return table.Retrieve(number)
+	}
+	return nil, errUnknownTable
+}
+
+// Ancients returns the length of the frozen items.
+func (f *freezer) Ancients() (uint64, error) {
+	return atomic.LoadUint64(&f.frozen), nil
+}
+
+// AncientSize returns the ancient size of the specified category.
+func (f *freezer) AncientSize(kind string) (uint64, error) {
+	if table := f.tables[kind]; table != nil {
+		return table.size()
+	}
+	return 0, errUnknownTable
+}
+
+// AppendAncient injects all binary blobs belong to block at the end of the
+// append-only immutable table files.
+//
+// Notably, this function is lock free but kind of thread-safe. All out-of-order
+// injection will be rejected. But if two injections with same number happen at
+// the same time, we can get into the trouble.
+func (f *freezer) AppendAncient(number uint64, hash, header, body, receipts, td []byte) (err error) {
+	// Ensure the binary blobs we are appending is continuous with freezer.
+	if atomic.LoadUint64(&f.frozen) != number {
+		return errOutOrderInsertion
+	}
+	// Rollback all inserted data if any insertion below failed to ensure
+	// the tables won't out of sync.
+	defer func() {
+		if err != nil {
+			rerr := f.repair()
+			if rerr != nil {
+				log.Crit("Failed to repair freezer", "err", rerr)
+			}
+			log.Info("Append ancient failed", "number", number, "err", err)
+		}
+	}()
+	// Inject all the components into the relevant data tables
+	if err := f.tables[freezerHashTable].Append(f.frozen, hash[:]); err != nil {
+		log.Error("Failed to append ancient hash", "number", f.frozen, "hash", hash, "err", err)
+		return err
+	}
+	if err := f.tables[freezerHeaderTable].Append(f.frozen, header); err != nil {
+		log.Error("Failed to append ancient header", "number", f.frozen, "hash", hash, "err", err)
+		return err
+	}
+	if err := f.tables[freezerBodiesTable].Append(f.frozen, body); err != nil {
+		log.Error("Failed to append ancient body", "number", f.frozen, "hash", hash, "err", err)
+		return err
+	}
+	if err := f.tables[freezerReceiptTable].Append(f.frozen, receipts); err != nil {
+		log.Error("Failed to append ancient receipts", "number", f.frozen, "hash", hash, "err", err)
+		return err
+	}
+	if err := f.tables[freezerDifficultyTable].Append(f.frozen, td); err != nil {
+		log.Error("Failed to append ancient difficulty", "number", f.frozen, "hash", hash, "err", err)
+		return err
+	}
+	atomic.AddUint64(&f.frozen, 1) // Only modify atomically
+	return nil
+}
+
+// Truncate discards any recent data above the provided threshold number.
+func (f *freezer) TruncateAncients(items uint64) error {
+	if atomic.LoadUint64(&f.frozen) <= items {
+		return nil
+	}
+	for _, table := range f.tables {
+		if err := table.truncate(items); err != nil {
+			return err
+		}
+	}
+	atomic.StoreUint64(&f.frozen, items)
+	return nil
+}
+
+// sync flushes all data tables to disk.
+func (f *freezer) Sync() error {
+	var errs []error
+	for _, table := range f.tables {
+		if err := table.Sync(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	if errs != nil {
+		return fmt.Errorf("%v", errs)
+	}
+	return nil
+}
+
+// freeze is a background thread that periodically checks the blockchain for any
+// import progress and moves ancient data from the fast database into the freezer.
+//
+// This functionality is deliberately broken off from block importing to avoid
+// incurring additional data shuffling delays on block propagation.
+func (f *freezer) freeze(db ethdb.KeyValueStore) {
+	nfdb := &nofreezedb{KeyValueStore: db}
+
+	for {
+		// Retrieve the freezing threshold.
+		hash := ReadHeadBlockHash(nfdb)
+		if hash == (common.Hash{}) {
+			log.Debug("Current full block hash unavailable") // new chain, empty database
+			time.Sleep(freezerRecheckInterval)
+			continue
+		}
+		number := ReadHeaderNumber(nfdb, hash)
+		switch {
+		case number == nil:
+			log.Error("Current full block number unavailable", "hash", hash)
+			time.Sleep(freezerRecheckInterval)
+			continue
+
+		case *number < params.ImmutabilityThreshold:
+			log.Debug("Current full block not old enough", "number", *number, "hash", hash, "delay", params.ImmutabilityThreshold)
+			time.Sleep(freezerRecheckInterval)
+			continue
+
+		case *number-params.ImmutabilityThreshold <= f.frozen:
+			log.Debug("Ancient blocks frozen already", "number", *number, "hash", hash, "frozen", f.frozen)
+			time.Sleep(freezerRecheckInterval)
+			continue
+		}
+		head := ReadHeader(nfdb, hash, *number)
+		if head == nil {
+			log.Error("Current full block unavailable", "number", *number, "hash", hash)
+			time.Sleep(freezerRecheckInterval)
+			continue
+		}
+		// Seems we have data ready to be frozen, process in usable batches
+		limit := *number - params.ImmutabilityThreshold
+		if limit-f.frozen > freezerBatchLimit {
+			limit = f.frozen + freezerBatchLimit
+		}
+		var (
+			start    = time.Now()
+			first    = f.frozen
+			ancients = make([]common.Hash, 0, limit)
+		)
+		for f.frozen < limit {
+			// Retrieves all the components of the canonical block
+			hash := ReadCanonicalHash(nfdb, f.frozen)
+			if hash == (common.Hash{}) {
+				log.Error("Canonical hash missing, can't freeze", "number", f.frozen)
+				break
+			}
+			header := ReadHeaderRLP(nfdb, hash, f.frozen)
+			if len(header) == 0 {
+				log.Error("Block header missing, can't freeze", "number", f.frozen, "hash", hash)
+				break
+			}
+			body := ReadBodyRLP(nfdb, hash, f.frozen)
+			if len(body) == 0 {
+				log.Error("Block body missing, can't freeze", "number", f.frozen, "hash", hash)
+				break
+			}
+			receipts := ReadReceiptsRLP(nfdb, hash, f.frozen)
+			if len(receipts) == 0 {
+				log.Error("Block receipts missing, can't freeze", "number", f.frozen, "hash", hash)
+				break
+			}
+			td := ReadTdRLP(nfdb, hash, f.frozen)
+			if len(td) == 0 {
+				log.Error("Total difficulty missing, can't freeze", "number", f.frozen, "hash", hash)
+				break
+			}
+			log.Trace("Deep froze ancient block", "number", f.frozen, "hash", hash)
+			// Inject all the components into the relevant data tables
+			if err := f.AppendAncient(f.frozen, hash[:], header, body, receipts, td); err != nil {
+				break
+			}
+			ancients = append(ancients, hash)
+		}
+		// Batch of blocks have been frozen, flush them before wiping from leveldb
+		if err := f.Sync(); err != nil {
+			log.Crit("Failed to flush frozen tables", "err", err)
+		}
+		// Wipe out all data from the active database
+		batch := db.NewBatch()
+		for i := 0; i < len(ancients); i++ {
+			DeleteBlockWithoutNumber(batch, ancients[i], first+uint64(i))
+			DeleteCanonicalHash(batch, first+uint64(i))
+		}
+		if err := batch.Write(); err != nil {
+			log.Crit("Failed to delete frozen canonical blocks", "err", err)
+		}
+		batch.Reset()
+		// Wipe out side chain also.
+		for number := first; number < f.frozen; number++ {
+			for _, hash := range ReadAllHashes(db, number) {
+				DeleteBlock(batch, hash, number)
+			}
+		}
+		if err := batch.Write(); err != nil {
+			log.Crit("Failed to delete frozen side blocks", "err", err)
+		}
+		// Log something friendly for the user
+		context := []interface{}{
+			"blocks", f.frozen - first, "elapsed", common.PrettyDuration(time.Since(start)), "number", f.frozen - 1,
+		}
+		if n := len(ancients); n > 0 {
+			context = append(context, []interface{}{"hash", ancients[n-1]}...)
+		}
+		log.Info("Deep froze chain segment", context...)
+
+		// Avoid database thrashing with tiny writes
+		if f.frozen-first < freezerBatchLimit {
+			time.Sleep(freezerRecheckInterval)
+		}
+	}
+}
+
+// repair truncates all data tables to the same length.
+func (f *freezer) repair() error {
+	min := uint64(math.MaxUint64)
+	for _, table := range f.tables {
+		items := atomic.LoadUint64(&table.items)
+		if min > items {
+			min = items
+		}
+	}
+	for _, table := range f.tables {
+		if err := table.truncate(min); err != nil {
+			return err
+		}
+	}
+	atomic.StoreUint64(&f.frozen, min)
+	return nil
+}
diff --git a/core/rawdb/freezer_table.go b/core/rawdb/freezer_table.go
new file mode 100644
index 000000000..673a181e4
--- /dev/null
+++ b/core/rawdb/freezer_table.go
@@ -0,0 +1,561 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/golang/snappy"
+)
+
+var (
+	// errClosed is returned if an operation attempts to read from or write to the
+	// freezer table after it has already been closed.
+	errClosed = errors.New("closed")
+
+	// errOutOfBounds is returned if the item requested is not contained within the
+	// freezer table.
+	errOutOfBounds = errors.New("out of bounds")
+
+	// errNotSupported is returned if the database doesn't support the required operation.
+	errNotSupported = errors.New("this operation is not supported")
+)
+
+// indexEntry contains the number/id of the file that the data resides in, aswell as the
+// offset within the file to the end of the data
+// In serialized form, the filenum is stored as uint16.
+type indexEntry struct {
+	filenum uint32 // stored as uint16 ( 2 bytes)
+	offset  uint32 // stored as uint32 ( 4 bytes)
+}
+
+const indexEntrySize = 6
+
+// unmarshallBinary deserializes binary b into the rawIndex entry.
+func (i *indexEntry) unmarshalBinary(b []byte) error {
+	i.filenum = uint32(binary.BigEndian.Uint16(b[:2]))
+	i.offset = binary.BigEndian.Uint32(b[2:6])
+	return nil
+}
+
+// marshallBinary serializes the rawIndex entry into binary.
+func (i *indexEntry) marshallBinary() []byte {
+	b := make([]byte, indexEntrySize)
+	binary.BigEndian.PutUint16(b[:2], uint16(i.filenum))
+	binary.BigEndian.PutUint32(b[2:6], i.offset)
+	return b
+}
+
+// freezerTable represents a single chained data table within the freezer (e.g. blocks).
+// It consists of a data file (snappy encoded arbitrary data blobs) and an indexEntry
+// file (uncompressed 64 bit indices into the data file).
+type freezerTable struct {
+	noCompression bool   // if true, disables snappy compression. Note: does not work retroactively
+	maxFileSize   uint32 // Max file size for data-files
+	name          string
+	path          string
+
+	head   *os.File            // File descriptor for the data head of the table
+	files  map[uint32]*os.File // open files
+	headId uint32              // number of the currently active head file
+	tailId uint32              // number of the earliest file
+	index  *os.File            // File descriptor for the indexEntry file of the table
+
+	// In the case that old items are deleted (from the tail), we use itemOffset
+	// to count how many historic items have gone missing.
+	items      uint64 // Number of items stored in the table (including items removed from tail)
+	itemOffset uint32 // Offset (number of discarded items)
+
+	headBytes  uint32        // Number of bytes written to the head file
+	readMeter  metrics.Meter // Meter for measuring the effective amount of data read
+	writeMeter metrics.Meter // Meter for measuring the effective amount of data written
+
+	logger log.Logger   // Logger with database path and table name ambedded
+	lock   sync.RWMutex // Mutex protecting the data file descriptors
+}
+
+// newTable opens a freezer table with default settings - 2G files
+func newTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, disableSnappy bool) (*freezerTable, error) {
+	return newCustomTable(path, name, readMeter, writeMeter, 2*1000*1000*1000, disableSnappy)
+}
+
+// newCustomTable opens a freezer table, creating the data and index files if they are
+// non existent. Both files are truncated to the shortest common length to ensure
+// they don't go out of sync.
+func newCustomTable(path string, name string, readMeter metrics.Meter, writeMeter metrics.Meter, maxFilesize uint32, noCompression bool) (*freezerTable, error) {
+	// Ensure the containing directory exists and open the indexEntry file
+	if err := os.MkdirAll(path, 0755); err != nil {
+		return nil, err
+	}
+	var idxName string
+	if noCompression {
+		// raw idx
+		idxName = fmt.Sprintf("%s.ridx", name)
+	} else {
+		// compressed idx
+		idxName = fmt.Sprintf("%s.cidx", name)
+	}
+	offsets, err := os.OpenFile(filepath.Join(path, idxName), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
+	if err != nil {
+		return nil, err
+	}
+	// Create the table and repair any past inconsistency
+	tab := &freezerTable{
+		index:         offsets,
+		files:         make(map[uint32]*os.File),
+		readMeter:     readMeter,
+		writeMeter:    writeMeter,
+		name:          name,
+		path:          path,
+		logger:        log.New("database", path, "table", name),
+		noCompression: noCompression,
+		maxFileSize:   maxFilesize,
+	}
+	if err := tab.repair(); err != nil {
+		tab.Close()
+		return nil, err
+	}
+	return tab, nil
+}
+
+// repair cross checks the head and the index file and truncates them to
+// be in sync with each other after a potential crash / data loss.
+func (t *freezerTable) repair() error {
+	// Create a temporary offset buffer to init files with and read indexEntry into
+	buffer := make([]byte, indexEntrySize)
+
+	// If we've just created the files, initialize the index with the 0 indexEntry
+	stat, err := t.index.Stat()
+	if err != nil {
+		return err
+	}
+	if stat.Size() == 0 {
+		if _, err := t.index.Write(buffer); err != nil {
+			return err
+		}
+	}
+	// Ensure the index is a multiple of indexEntrySize bytes
+	if overflow := stat.Size() % indexEntrySize; overflow != 0 {
+		t.index.Truncate(stat.Size() - overflow) // New file can't trigger this path
+	}
+	// Retrieve the file sizes and prepare for truncation
+	if stat, err = t.index.Stat(); err != nil {
+		return err
+	}
+	offsetsSize := stat.Size()
+
+	// Open the head file
+	var (
+		firstIndex  indexEntry
+		lastIndex   indexEntry
+		contentSize int64
+		contentExp  int64
+	)
+	// Read index zero, determine what file is the earliest
+	// and what item offset to use
+	t.index.ReadAt(buffer, 0)
+	firstIndex.unmarshalBinary(buffer)
+
+	t.tailId = firstIndex.offset
+	t.itemOffset = firstIndex.filenum
+
+	t.index.ReadAt(buffer, offsetsSize-indexEntrySize)
+	lastIndex.unmarshalBinary(buffer)
+	t.head, err = t.openFile(lastIndex.filenum, os.O_RDWR|os.O_CREATE|os.O_APPEND)
+	if err != nil {
+		return err
+	}
+	if stat, err = t.head.Stat(); err != nil {
+		return err
+	}
+	contentSize = stat.Size()
+
+	// Keep truncating both files until they come in sync
+	contentExp = int64(lastIndex.offset)
+
+	for contentExp != contentSize {
+		// Truncate the head file to the last offset pointer
+		if contentExp < contentSize {
+			t.logger.Warn("Truncating dangling head", "indexed", common.StorageSize(contentExp), "stored", common.StorageSize(contentSize))
+			if err := t.head.Truncate(contentExp); err != nil {
+				return err
+			}
+			contentSize = contentExp
+		}
+		// Truncate the index to point within the head file
+		if contentExp > contentSize {
+			t.logger.Warn("Truncating dangling indexes", "indexed", common.StorageSize(contentExp), "stored", common.StorageSize(contentSize))
+			if err := t.index.Truncate(offsetsSize - indexEntrySize); err != nil {
+				return err
+			}
+			offsetsSize -= indexEntrySize
+			t.index.ReadAt(buffer, offsetsSize-indexEntrySize)
+			var newLastIndex indexEntry
+			newLastIndex.unmarshalBinary(buffer)
+			// We might have slipped back into an earlier head-file here
+			if newLastIndex.filenum != lastIndex.filenum {
+				// release earlier opened file
+				t.releaseFile(lastIndex.filenum)
+				t.head, err = t.openFile(newLastIndex.filenum, os.O_RDWR|os.O_CREATE|os.O_APPEND)
+				if stat, err = t.head.Stat(); err != nil {
+					// TODO, anything more we can do here?
+					// A data file has gone missing...
+					return err
+				}
+				contentSize = stat.Size()
+			}
+			lastIndex = newLastIndex
+			contentExp = int64(lastIndex.offset)
+		}
+	}
+	// Ensure all reparation changes have been written to disk
+	if err := t.index.Sync(); err != nil {
+		return err
+	}
+	if err := t.head.Sync(); err != nil {
+		return err
+	}
+	// Update the item and byte counters and return
+	t.items = uint64(t.itemOffset) + uint64(offsetsSize/indexEntrySize-1) // last indexEntry points to the end of the data file
+	t.headBytes = uint32(contentSize)
+	t.headId = lastIndex.filenum
+
+	// Close opened files and preopen all files
+	if err := t.preopen(); err != nil {
+		return err
+	}
+	t.logger.Debug("Chain freezer table opened", "items", t.items, "size", common.StorageSize(t.headBytes))
+	return nil
+}
+
+// preopen opens all files that the freezer will need. This method should be called from an init-context,
+// since it assumes that it doesn't have to bother with locking
+// The rationale for doing preopen is to not have to do it from within Retrieve, thus not needing to ever
+// obtain a write-lock within Retrieve.
+func (t *freezerTable) preopen() (err error) {
+	// The repair might have already opened (some) files
+	t.releaseFilesAfter(0, false)
+	// Open all except head in RDONLY
+	for i := t.tailId; i < t.headId; i++ {
+		if _, err = t.openFile(i, os.O_RDONLY); err != nil {
+			return err
+		}
+	}
+	// Open head in read/write
+	t.head, err = t.openFile(t.headId, os.O_RDWR|os.O_CREATE|os.O_APPEND)
+	return err
+}
+
+// truncate discards any recent data above the provided threashold number.
+func (t *freezerTable) truncate(items uint64) error {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	// If our item count is correct, don't do anything
+	if atomic.LoadUint64(&t.items) <= items {
+		return nil
+	}
+	// Something's out of sync, truncate the table's offset index
+	t.logger.Warn("Truncating freezer table", "items", t.items, "limit", items)
+	if err := t.index.Truncate(int64(items+1) * indexEntrySize); err != nil {
+		return err
+	}
+	// Calculate the new expected size of the data file and truncate it
+	buffer := make([]byte, indexEntrySize)
+	if _, err := t.index.ReadAt(buffer, int64(items*indexEntrySize)); err != nil {
+		return err
+	}
+	var expected indexEntry
+	expected.unmarshalBinary(buffer)
+
+	// We might need to truncate back to older files
+	if expected.filenum != t.headId {
+		// If already open for reading, force-reopen for writing
+		t.releaseFile(expected.filenum)
+		newHead, err := t.openFile(expected.filenum, os.O_RDWR|os.O_CREATE|os.O_APPEND)
+		if err != nil {
+			return err
+		}
+		// release any files _after the current head -- both the previous head
+		// and any files which may have been opened for reading
+		t.releaseFilesAfter(expected.filenum, true)
+		// set back the historic head
+		t.head = newHead
+		atomic.StoreUint32(&t.headId, expected.filenum)
+	}
+	if err := t.head.Truncate(int64(expected.offset)); err != nil {
+		return err
+	}
+	// All data files truncated, set internal counters and return
+	atomic.StoreUint64(&t.items, items)
+	atomic.StoreUint32(&t.headBytes, expected.offset)
+	return nil
+}
+
+// Close closes all opened files.
+func (t *freezerTable) Close() error {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
+	var errs []error
+	if err := t.index.Close(); err != nil {
+		errs = append(errs, err)
+	}
+	t.index = nil
+
+	for _, f := range t.files {
+		if err := f.Close(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	t.head = nil
+
+	if errs != nil {
+		return fmt.Errorf("%v", errs)
+	}
+	return nil
+}
+
+// openFile assumes that the write-lock is held by the caller
+func (t *freezerTable) openFile(num uint32, flag int) (f *os.File, err error) {
+	var exist bool
+	if f, exist = t.files[num]; !exist {
+		var name string
+		if t.noCompression {
+			name = fmt.Sprintf("%s.%04d.rdat", t.name, num)
+		} else {
+			name = fmt.Sprintf("%s.%04d.cdat", t.name, num)
+		}
+		f, err = os.OpenFile(filepath.Join(t.path, name), flag, 0644)
+		if err != nil {
+			return nil, err
+		}
+		t.files[num] = f
+	}
+	return f, err
+}
+
+// releaseFile closes a file, and removes it from the open file cache.
+// Assumes that the caller holds the write lock
+func (t *freezerTable) releaseFile(num uint32) {
+	if f, exist := t.files[num]; exist {
+		delete(t.files, num)
+		f.Close()
+	}
+}
+
+// releaseFilesAfter closes all open files with a higher number, and optionally also deletes the files
+func (t *freezerTable) releaseFilesAfter(num uint32, remove bool) {
+	for fnum, f := range t.files {
+		if fnum > num {
+			delete(t.files, fnum)
+			f.Close()
+			if remove {
+				os.Remove(f.Name())
+			}
+		}
+	}
+}
+
+// Append injects a binary blob at the end of the freezer table. The item number
+// is a precautionary parameter to ensure data correctness, but the table will
+// reject already existing data.
+//
+// Note, this method will *not* flush any data to disk so be sure to explicitly
+// fsync before irreversibly deleting data from the database.
+func (t *freezerTable) Append(item uint64, blob []byte) error {
+	// Read lock prevents competition with truncate
+	t.lock.RLock()
+	// Ensure the table is still accessible
+	if t.index == nil || t.head == nil {
+		t.lock.RUnlock()
+		return errClosed
+	}
+	// Ensure only the next item can be written, nothing else
+	if atomic.LoadUint64(&t.items) != item {
+		t.lock.RUnlock()
+		return fmt.Errorf("appending unexpected item: want %d, have %d", t.items, item)
+	}
+	// Encode the blob and write it into the data file
+	if !t.noCompression {
+		blob = snappy.Encode(nil, blob)
+	}
+	bLen := uint32(len(blob))
+	if t.headBytes+bLen < bLen ||
+		t.headBytes+bLen > t.maxFileSize {
+		// we need a new file, writing would overflow
+		t.lock.RUnlock()
+		t.lock.Lock()
+		nextId := atomic.LoadUint32(&t.headId) + 1
+		// We open the next file in truncated mode -- if this file already
+		// exists, we need to start over from scratch on it
+		newHead, err := t.openFile(nextId, os.O_RDWR|os.O_CREATE|os.O_TRUNC)
+		if err != nil {
+			t.lock.Unlock()
+			return err
+		}
+		// Close old file, and reopen in RDONLY mode
+		t.releaseFile(t.headId)
+		t.openFile(t.headId, os.O_RDONLY)
+
+		// Swap out the current head
+		t.head = newHead
+		atomic.StoreUint32(&t.headBytes, 0)
+		atomic.StoreUint32(&t.headId, nextId)
+		t.lock.Unlock()
+		t.lock.RLock()
+	}
+
+	defer t.lock.RUnlock()
+
+	if _, err := t.head.Write(blob); err != nil {
+		return err
+	}
+	newOffset := atomic.AddUint32(&t.headBytes, bLen)
+	idx := indexEntry{
+		filenum: atomic.LoadUint32(&t.headId),
+		offset:  newOffset,
+	}
+	// Write indexEntry
+	t.index.Write(idx.marshallBinary())
+	t.writeMeter.Mark(int64(bLen + indexEntrySize))
+	atomic.AddUint64(&t.items, 1)
+	return nil
+}
+
+// getBounds returns the indexes for the item
+// returns start, end, filenumber and error
+func (t *freezerTable) getBounds(item uint64) (uint32, uint32, uint32, error) {
+	var startIdx, endIdx indexEntry
+	buffer := make([]byte, indexEntrySize)
+	if _, err := t.index.ReadAt(buffer, int64(item*indexEntrySize)); err != nil {
+		return 0, 0, 0, err
+	}
+	startIdx.unmarshalBinary(buffer)
+	if _, err := t.index.ReadAt(buffer, int64((item+1)*indexEntrySize)); err != nil {
+		return 0, 0, 0, err
+	}
+	endIdx.unmarshalBinary(buffer)
+	if startIdx.filenum != endIdx.filenum {
+		// If a piece of data 'crosses' a data-file,
+		// it's actually in one piece on the second data-file.
+		// We return a zero-indexEntry for the second file as start
+		return 0, endIdx.offset, endIdx.filenum, nil
+	}
+	return startIdx.offset, endIdx.offset, endIdx.filenum, nil
+}
+
+// Retrieve looks up the data offset of an item with the given number and retrieves
+// the raw binary blob from the data file.
+func (t *freezerTable) Retrieve(item uint64) ([]byte, error) {
+	// Ensure the table and the item is accessible
+	if t.index == nil || t.head == nil {
+		return nil, errClosed
+	}
+	if atomic.LoadUint64(&t.items) <= item {
+		return nil, errOutOfBounds
+	}
+	// Ensure the item was not deleted from the tail either
+	offset := atomic.LoadUint32(&t.itemOffset)
+	if uint64(offset) > item {
+		return nil, errOutOfBounds
+	}
+	t.lock.RLock()
+	startOffset, endOffset, filenum, err := t.getBounds(item - uint64(offset))
+	if err != nil {
+		t.lock.RUnlock()
+		return nil, err
+	}
+	dataFile, exist := t.files[filenum]
+	if !exist {
+		t.lock.RUnlock()
+		return nil, fmt.Errorf("missing data file %d", filenum)
+	}
+	// Retrieve the data itself, decompress and return
+	blob := make([]byte, endOffset-startOffset)
+	if _, err := dataFile.ReadAt(blob, int64(startOffset)); err != nil {
+		t.lock.RUnlock()
+		return nil, err
+	}
+	t.lock.RUnlock()
+	t.readMeter.Mark(int64(len(blob) + 2*indexEntrySize))
+
+	if t.noCompression {
+		return blob, nil
+	}
+	return snappy.Decode(nil, blob)
+}
+
+// has returns an indicator whether the specified number data
+// exists in the freezer table.
+func (t *freezerTable) has(number uint64) bool {
+	return atomic.LoadUint64(&t.items) > number
+}
+
+// size returns the total data size in the freezer table.
+func (t *freezerTable) size() (uint64, error) {
+	t.lock.RLock()
+	defer t.lock.RUnlock()
+
+	stat, err := t.index.Stat()
+	if err != nil {
+		return 0, err
+	}
+	total := uint64(t.maxFileSize)*uint64(t.headId-t.tailId) + uint64(t.headBytes) + uint64(stat.Size())
+	return total, nil
+}
+
+// Sync pushes any pending data from memory out to disk. This is an expensive
+// operation, so use it with care.
+func (t *freezerTable) Sync() error {
+	if err := t.index.Sync(); err != nil {
+		return err
+	}
+	return t.head.Sync()
+}
+
+// printIndex is a debug print utility function for testing
+func (t *freezerTable) printIndex() {
+	buf := make([]byte, indexEntrySize)
+
+	fmt.Printf("|-----------------|\n")
+	fmt.Printf("| fileno | offset |\n")
+	fmt.Printf("|--------+--------|\n")
+
+	for i := uint64(0); ; i++ {
+		if _, err := t.index.ReadAt(buf, int64(i*indexEntrySize)); err != nil {
+			break
+		}
+		var entry indexEntry
+		entry.unmarshalBinary(buf)
+		fmt.Printf("|  %03d   |  %03d   | \n", entry.filenum, entry.offset)
+		if i > 100 {
+			fmt.Printf(" ... \n")
+			break
+		}
+	}
+	fmt.Printf("|-----------------|\n")
+}
diff --git a/core/rawdb/freezer_table_test.go b/core/rawdb/freezer_table_test.go
new file mode 100644
index 000000000..e63fb63a3
--- /dev/null
+++ b/core/rawdb/freezer_table_test.go
@@ -0,0 +1,609 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/metrics"
+)
+
+func init() {
+	rand.Seed(time.Now().Unix())
+}
+
+// Gets a chunk of data, filled with 'b'
+func getChunk(size int, b int) []byte {
+	data := make([]byte, size)
+	for i := range data {
+		data[i] = byte(b)
+	}
+	return data
+}
+
+func print(t *testing.T, f *freezerTable, item uint64) {
+	a, err := f.Retrieve(item)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fmt.Printf("db[%d] =  %x\n", item, a)
+}
+
+// TestFreezerBasics test initializing a freezertable from scratch, writing to the table,
+// and reading it back.
+func TestFreezerBasics(t *testing.T) {
+	t.Parallel()
+	// set cutoff at 50 bytes
+	f, err := newCustomTable(os.TempDir(),
+		fmt.Sprintf("unittest-%d", rand.Uint64()),
+		metrics.NewMeter(), metrics.NewMeter(), 50, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	// Write 15 bytes 255 times, results in 85 files
+	for x := 0; x < 255; x++ {
+		data := getChunk(15, x)
+		f.Append(uint64(x), data)
+	}
+
+	//print(t, f, 0)
+	//print(t, f, 1)
+	//print(t, f, 2)
+	//
+	//db[0] =  000000000000000000000000000000
+	//db[1] =  010101010101010101010101010101
+	//db[2] =  020202020202020202020202020202
+
+	for y := 0; y < 255; y++ {
+		exp := getChunk(15, y)
+		got, err := f.Retrieve(uint64(y))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !bytes.Equal(got, exp) {
+			t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
+		}
+	}
+	// Check that we cannot read too far
+	_, err = f.Retrieve(uint64(255))
+	if err != errOutOfBounds {
+		t.Fatal(err)
+	}
+}
+
+// TestFreezerBasicsClosing tests same as TestFreezerBasics, but also closes and reopens the freezer between
+// every operation
+func TestFreezerBasicsClosing(t *testing.T) {
+	t.Parallel()
+	// set cutoff at 50 bytes
+	var (
+		fname  = fmt.Sprintf("basics-close-%d", rand.Uint64())
+		m1, m2 = metrics.NewMeter(), metrics.NewMeter()
+		f      *freezerTable
+		err    error
+	)
+	f, err = newCustomTable(os.TempDir(), fname, m1, m2, 50, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Write 15 bytes 255 times, results in 85 files
+	for x := 0; x < 255; x++ {
+		data := getChunk(15, x)
+		f.Append(uint64(x), data)
+		f.Close()
+		f, err = newCustomTable(os.TempDir(), fname, m1, m2, 50, true)
+	}
+	defer f.Close()
+
+	for y := 0; y < 255; y++ {
+		exp := getChunk(15, y)
+		got, err := f.Retrieve(uint64(y))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !bytes.Equal(got, exp) {
+			t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
+		}
+		f.Close()
+		f, err = newCustomTable(os.TempDir(), fname, m1, m2, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+// TestFreezerRepairDanglingHead tests that we can recover if index entries are removed
+func TestFreezerRepairDanglingHead(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
+
+	{ // Fill table
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 255 times
+		for x := 0; x < 255; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		// The last item should be there
+		if _, err = f.Retrieve(0xfe); err != nil {
+			t.Fatal(err)
+		}
+		f.Close()
+	}
+	// open the index
+	idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
+	if err != nil {
+		t.Fatalf("Failed to open index file: %v", err)
+	}
+	// Remove 4 bytes
+	stat, err := idxFile.Stat()
+	if err != nil {
+		t.Fatalf("Failed to stat index file: %v", err)
+	}
+	idxFile.Truncate(stat.Size() - 4)
+	idxFile.Close()
+	// Now open it again
+	{
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		// The last item should be missing
+		if _, err = f.Retrieve(0xff); err == nil {
+			t.Errorf("Expected error for missing index entry")
+		}
+		// The one before should still be there
+		if _, err = f.Retrieve(0xfd); err != nil {
+			t.Fatalf("Expected no error, got %v", err)
+		}
+	}
+}
+
+// TestFreezerRepairDanglingHeadLarge tests that we can recover if very many index entries are removed
+func TestFreezerRepairDanglingHeadLarge(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
+
+	{ // Fill a table and close it
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 255 times
+		for x := 0; x < 0xff; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		// The last item should be there
+		if _, err = f.Retrieve(f.items - 1); err == nil {
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
+		f.Close()
+	}
+	// open the index
+	idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
+	if err != nil {
+		t.Fatalf("Failed to open index file: %v", err)
+	}
+	// Remove everything but the first item, and leave data unaligned
+	// 0-indexEntry, 1-indexEntry, corrupt-indexEntry
+	idxFile.Truncate(indexEntrySize + indexEntrySize + indexEntrySize/2)
+	idxFile.Close()
+	// Now open it again
+	{
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		// The first item should be there
+		if _, err = f.Retrieve(0); err != nil {
+			t.Fatal(err)
+		}
+		// The second item should be missing
+		if _, err = f.Retrieve(1); err == nil {
+			t.Errorf("Expected error for missing index entry")
+		}
+		// We should now be able to store items again, from item = 1
+		for x := 1; x < 0xff; x++ {
+			data := getChunk(15, ^x)
+			f.Append(uint64(x), data)
+		}
+		f.Close()
+	}
+	// And if we open it, we should now be able to read all of them (new values)
+	{
+		f, _ := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		for y := 1; y < 255; y++ {
+			exp := getChunk(15, ^y)
+			got, err := f.Retrieve(uint64(y))
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !bytes.Equal(got, exp) {
+				t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
+			}
+		}
+	}
+}
+
+// TestSnappyDetection tests that we fail to open a snappy database and vice versa
+func TestSnappyDetection(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("snappytest-%d", rand.Uint64())
+	// Open with snappy
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 255 times
+		for x := 0; x < 0xff; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		f.Close()
+	}
+	// Open without snappy
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, false)
+		if _, err = f.Retrieve(0); err == nil {
+			f.Close()
+			t.Fatalf("expected empty table")
+		}
+	}
+
+	// Open with snappy
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		// There should be 255 items
+		if _, err = f.Retrieve(0xfe); err != nil {
+			f.Close()
+			t.Fatalf("expected no error, got %v", err)
+		}
+	}
+
+}
+func assertFileSize(f string, size int64) error {
+	stat, err := os.Stat(f)
+	if err != nil {
+		return err
+	}
+	if stat.Size() != size {
+		return fmt.Errorf("error, expected size %d, got %d", size, stat.Size())
+	}
+	return nil
+
+}
+
+// TestFreezerRepairDanglingIndex checks that if the index has more entries than there are data,
+// the index is repaired
+func TestFreezerRepairDanglingIndex(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("dangling_indextest-%d", rand.Uint64())
+
+	{ // Fill a table and close it
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 9 times : 150 bytes
+		for x := 0; x < 9; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		// The last item should be there
+		if _, err = f.Retrieve(f.items - 1); err != nil {
+			f.Close()
+			t.Fatal(err)
+		}
+		f.Close()
+		// File sizes should be 45, 45, 45 : items[3, 3, 3)
+	}
+	// Crop third file
+	fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0002.rdat", fname))
+	// Truncate third file: 45 ,45, 20
+	{
+		if err := assertFileSize(fileToCrop, 45); err != nil {
+			t.Fatal(err)
+		}
+		file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
+		if err != nil {
+			t.Fatal(err)
+		}
+		file.Truncate(20)
+		file.Close()
+	}
+	// Open db it again
+	// It should restore the file(s) to
+	// 45, 45, 15
+	// with 3+3+1 items
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if f.items != 7 {
+			f.Close()
+			t.Fatalf("expected %d items, got %d", 7, f.items)
+		}
+		if err := assertFileSize(fileToCrop, 15); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestFreezerTruncate(t *testing.T) {
+
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("truncation-%d", rand.Uint64())
+
+	{ // Fill table
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 30 times
+		for x := 0; x < 30; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		// The last item should be there
+		if _, err = f.Retrieve(f.items - 1); err != nil {
+			t.Fatal(err)
+		}
+		f.Close()
+	}
+	// Reopen, truncate
+	{
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+		f.truncate(10) // 150 bytes
+		if f.items != 10 {
+			t.Fatalf("expected %d items, got %d", 10, f.items)
+		}
+		// 45, 45, 45, 15 -- bytes should be 15
+		if f.headBytes != 15 {
+			t.Fatalf("expected %d bytes, got %d", 15, f.headBytes)
+		}
+
+	}
+
+}
+
+// TestFreezerRepairFirstFile tests a head file with the very first item only half-written.
+// That will rewind the index, and _should_ truncate the head file
+func TestFreezerRepairFirstFile(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("truncationfirst-%d", rand.Uint64())
+	{ // Fill table
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 80 bytes, splitting out into two files
+		f.Append(0, getChunk(40, 0xFF))
+		f.Append(1, getChunk(40, 0xEE))
+		// The last item should be there
+		if _, err = f.Retrieve(f.items - 1); err != nil {
+			t.Fatal(err)
+		}
+		f.Close()
+	}
+	// Truncate the file in half
+	fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0001.rdat", fname))
+	{
+		if err := assertFileSize(fileToCrop, 40); err != nil {
+			t.Fatal(err)
+		}
+		file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
+		if err != nil {
+			t.Fatal(err)
+		}
+		file.Truncate(20)
+		file.Close()
+	}
+	// Reopen
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if f.items != 1 {
+			f.Close()
+			t.Fatalf("expected %d items, got %d", 0, f.items)
+		}
+		// Write 40 bytes
+		f.Append(1, getChunk(40, 0xDD))
+		f.Close()
+		// Should have been truncated down to zero and then 40 written
+		if err := assertFileSize(fileToCrop, 40); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+// TestFreezerReadAndTruncate tests:
+// - we have a table open
+// - do some reads, so files are open in readonly
+// - truncate so those files are 'removed'
+// - check that we did not keep the rdonly file descriptors
+func TestFreezerReadAndTruncate(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("read_truncate-%d", rand.Uint64())
+	{ // Fill table
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 15 bytes 30 times
+		for x := 0; x < 30; x++ {
+			data := getChunk(15, x)
+			f.Append(uint64(x), data)
+		}
+		// The last item should be there
+		if _, err = f.Retrieve(f.items - 1); err != nil {
+			t.Fatal(err)
+		}
+		f.Close()
+	}
+	// Reopen and read all files
+	{
+		f, err := newCustomTable(os.TempDir(), fname, wm, rm, 50, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if f.items != 30 {
+			f.Close()
+			t.Fatalf("expected %d items, got %d", 0, f.items)
+		}
+		for y := byte(0); y < 30; y++ {
+			f.Retrieve(uint64(y))
+		}
+		// Now, truncate back to zero
+		f.truncate(0)
+		// Write the data again
+		for x := 0; x < 30; x++ {
+			data := getChunk(15, ^x)
+			if err := f.Append(uint64(x), data); err != nil {
+				t.Fatalf("error %v", err)
+			}
+		}
+		f.Close()
+	}
+}
+
+func TestOffset(t *testing.T) {
+	t.Parallel()
+	wm, rm := metrics.NewMeter(), metrics.NewMeter()
+	fname := fmt.Sprintf("offset-%d", rand.Uint64())
+	{ // Fill table
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 40, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		// Write 6 x 20 bytes, splitting out into three files
+		f.Append(0, getChunk(20, 0xFF))
+		f.Append(1, getChunk(20, 0xEE))
+
+		f.Append(2, getChunk(20, 0xdd))
+		f.Append(3, getChunk(20, 0xcc))
+
+		f.Append(4, getChunk(20, 0xbb))
+		f.Append(5, getChunk(20, 0xaa))
+		f.printIndex()
+		f.Close()
+	}
+	// Now crop it.
+	{
+		// delete files 0 and 1
+		for i := 0; i < 2; i++ {
+			p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.%04d.rdat", fname, i))
+			if err := os.Remove(p); err != nil {
+				t.Fatal(err)
+			}
+		}
+		// Read the index file
+		p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.ridx", fname))
+		indexFile, err := os.OpenFile(p, os.O_RDWR, 0644)
+		if err != nil {
+			t.Fatal(err)
+		}
+		indexBuf := make([]byte, 7*indexEntrySize)
+		indexFile.Read(indexBuf)
+
+		// Update the index file, so that we store
+		// [ file = 2, offset = 4 ] at index zero
+
+		tailId := uint32(2)     // First file is 2
+		itemOffset := uint32(4) // We have removed four items
+		zeroIndex := indexEntry{
+			offset:  tailId,
+			filenum: itemOffset,
+		}
+		buf := zeroIndex.marshallBinary()
+		// Overwrite index zero
+		copy(indexBuf, buf)
+		// Remove the four next indices by overwriting
+		copy(indexBuf[indexEntrySize:], indexBuf[indexEntrySize*5:])
+		indexFile.WriteAt(indexBuf, 0)
+		// Need to truncate the moved index items
+		indexFile.Truncate(indexEntrySize * (1 + 2))
+		indexFile.Close()
+
+	}
+	// Now open again
+	{
+		f, err := newCustomTable(os.TempDir(), fname, rm, wm, 40, true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		f.printIndex()
+		// It should allow writing item 6
+		f.Append(6, getChunk(20, 0x99))
+
+		// It should be fine to fetch 4,5,6
+		if got, err := f.Retrieve(4); err != nil {
+			t.Fatal(err)
+		} else if exp := getChunk(20, 0xbb); !bytes.Equal(got, exp) {
+			t.Fatalf("expected %x got %x", exp, got)
+		}
+		if got, err := f.Retrieve(5); err != nil {
+			t.Fatal(err)
+		} else if exp := getChunk(20, 0xaa); !bytes.Equal(got, exp) {
+			t.Fatalf("expected %x got %x", exp, got)
+		}
+		if got, err := f.Retrieve(6); err != nil {
+			t.Fatal(err)
+		} else if exp := getChunk(20, 0x99); !bytes.Equal(got, exp) {
+			t.Fatalf("expected %x got %x", exp, got)
+		}
+
+		// It should error at 0, 1,2,3
+		for i := 0; i < 4; i++ {
+			if _, err := f.Retrieve(uint64(i)); err == nil {
+				t.Fatal("expected err")
+			}
+		}
+	}
+}
+
+// TODO (?)
+// - test that if we remove several head-files, aswell as data last data-file,
+//   the index is truncated accordingly
+// Right now, the freezer would fail on these conditions:
+// 1. have data files d0, d1, d2, d3
+// 2. remove d2,d3
+//
+// However, all 'normal' failure modes arising due to failing to sync() or save a file should be
+// handled already, and the case described above can only (?) happen if an external process/user
+// deletes files from the filesystem.
diff --git a/core/rawdb/schema.go b/core/rawdb/schema.go
index 62b60e2f3..a44a2c99f 100644
--- a/core/rawdb/schema.go
+++ b/core/rawdb/schema.go
@@ -63,6 +63,33 @@ var (
 	preimageHitCounter = metrics.NewRegisteredCounter("db/preimage/hits", nil)
 )
 
+const (
+	// freezerHeaderTable indicates the name of the freezer header table.
+	freezerHeaderTable = "headers"
+
+	// freezerHashTable indicates the name of the freezer canonical hash table.
+	freezerHashTable = "hashes"
+
+	// freezerBodiesTable indicates the name of the freezer block body table.
+	freezerBodiesTable = "bodies"
+
+	// freezerReceiptTable indicates the name of the freezer receipts table.
+	freezerReceiptTable = "receipts"
+
+	// freezerDifficultyTable indicates the name of the freezer total difficulty table.
+	freezerDifficultyTable = "diffs"
+)
+
+// freezerNoSnappy configures whether compression is disabled for the ancient-tables.
+// Hashes and difficulties don't compress well.
+var freezerNoSnappy = map[string]bool{
+	freezerHeaderTable:     false,
+	freezerHashTable:       true,
+	freezerBodiesTable:     false,
+	freezerReceiptTable:    false,
+	freezerDifficultyTable: true,
+}
+
 // LegacyTxLookupEntry is the legacy TxLookupEntry definition with some unnecessary
 // fields.
 type LegacyTxLookupEntry struct {
diff --git a/core/rawdb/table.go b/core/rawdb/table.go
index 0e50db7c9..6610b7f5a 100644
--- a/core/rawdb/table.go
+++ b/core/rawdb/table.go
@@ -50,6 +50,48 @@ func (t *table) Get(key []byte) ([]byte, error) {
 	return t.db.Get(append([]byte(t.prefix), key...))
 }
 
+// HasAncient is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) HasAncient(kind string, number uint64) (bool, error) {
+	return t.db.HasAncient(kind, number)
+}
+
+// Ancient is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) Ancient(kind string, number uint64) ([]byte, error) {
+	return t.db.Ancient(kind, number)
+}
+
+// Ancients is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) Ancients() (uint64, error) {
+	return t.db.Ancients()
+}
+
+// AncientSize is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) AncientSize(kind string) (uint64, error) {
+	return t.db.AncientSize(kind)
+}
+
+// AppendAncient is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) AppendAncient(number uint64, hash, header, body, receipts, td []byte) error {
+	return t.db.AppendAncient(number, hash, header, body, receipts, td)
+}
+
+// TruncateAncients is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) TruncateAncients(items uint64) error {
+	return t.db.TruncateAncients(items)
+}
+
+// Sync is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) Sync() error {
+	return t.db.Sync()
+}
+
 // Put inserts the given value into the database at a prefixed version of the
 // provided key.
 func (t *table) Put(key []byte, value []byte) error {
@@ -157,6 +199,6 @@ func (b *tableBatch) Reset() {
 }
 
 // Replay replays the batch contents.
-func (b *tableBatch) Replay(w ethdb.Writer) error {
+func (b *tableBatch) Replay(w ethdb.KeyValueWriter) error {
 	return b.batch.Replay(w)
 }
diff --git a/core/state/database.go b/core/state/database.go
index 8798b7380..ecc2c134d 100644
--- a/core/state/database.go
+++ b/core/state/database.go
@@ -93,7 +93,7 @@ type Trie interface {
 	// If the trie does not contain a value for key, the returned proof contains all
 	// nodes of the longest existing prefix of the key (at least the root), ending
 	// with the node that proves the absence of the key.
-	Prove(key []byte, fromLevel uint, proofDb ethdb.Writer) error
+	Prove(key []byte, fromLevel uint, proofDb ethdb.KeyValueWriter) error
 }
 
 // NewDatabase creates a backing store for state. The returned database is safe for
diff --git a/core/state/sync.go b/core/state/sync.go
index e4a08d293..ef7930527 100644
--- a/core/state/sync.go
+++ b/core/state/sync.go
@@ -26,7 +26,7 @@ import (
 )
 
 // NewStateSync create a new state trie download scheduler.
-func NewStateSync(root common.Hash, database ethdb.Reader, bloom *trie.SyncBloom) *trie.Sync {
+func NewStateSync(root common.Hash, database ethdb.KeyValueReader, bloom *trie.SyncBloom) *trie.Sync {
 	var syncer *trie.Sync
 	callback := func(leaf []byte, parent common.Hash) error {
 		var obj Account