Merge pull request #1779 from karalabe/split-block-storage-3000

core: split the db blocks into components, move TD out top level

18 files changed, 881 insertions, 381 deletions

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index f72f69791..ba753a493 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -528,17 +528,16 @@ func blockRecovery(ctx *cli.Context) {
 
 	var block *types.Block
 	if arg[0] == '#' {
-		block = core.GetBlockByNumber(blockDb, common.String2Big(arg[1:]).Uint64())
+		block = core.GetBlock(blockDb, core.GetCanonicalHash(blockDb, common.String2Big(arg[1:]).Uint64()))
 	} else {
-		block = core.GetBlockByHash(blockDb, common.HexToHash(arg))
+		block = core.GetBlock(blockDb, common.HexToHash(arg))
 	}
 
 	if block == nil {
 		glog.Fatalln("block not found. Recovery failed")
 	}
 
-	err = core.WriteHead(blockDb, block)
-	if err != nil {
+	if err = core.WriteHeadBlockHash(blockDb, block.Hash()); err != nil {
 		glog.Fatalln("block write err", err)
 	}
 	glog.Infof("Recovery succesful. New HEAD %x\n", block.Hash())
diff --git a/core/chain_makers.go b/core/chain_makers.go
index b009e0c28..f89218f82 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -158,7 +158,6 @@ func GenerateChain(parent *types.Block, db common.Database, n int, gen func(int,
 	for i := 0; i < n; i++ {
 		header := makeHeader(parent, statedb)
 		block := genblock(i, header)
-		block.Td = CalcTD(block, parent)
 		blocks[i] = block
 		parent = block
 	}
diff --git a/core/chain_manager.go b/core/chain_manager.go
index c8127951e..407945f8e 100644
--- a/core/chain_manager.go
+++ b/core/chain_manager.go
@@ -35,6 +35,7 @@ import (
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/pow"
+	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/hashicorp/golang-lru"
 )
 
@@ -48,6 +49,9 @@ var (
 )
 
 const (
+	headerCacheLimit    = 512
+	bodyCacheLimit      = 256
+	tdCacheLimit        = 1024
 	blockCacheLimit     = 256
 	maxFutureBlocks     = 256
 	maxTimeFutureBlocks = 30
@@ -68,10 +72,13 @@ type ChainManager struct {
 	checkpoint      int // checkpoint counts towards the new checkpoint
 	td              *big.Int
 	currentBlock    *types.Block
-	lastBlockHash   common.Hash
 	currentGasLimit *big.Int
 
-	cache        *lru.Cache // cache is the LRU caching
+	headerCache  *lru.Cache // Cache for the most recent block headers
+	bodyCache    *lru.Cache // Cache for the most recent block bodies
+	bodyRLPCache *lru.Cache // Cache for the most recent block bodies in RLP encoded format
+	tdCache      *lru.Cache // Cache for the most recent block total difficulties
+	blockCache   *lru.Cache // Cache for the most recent entire blocks
 	futureBlocks *lru.Cache // future blocks are blocks added for later processing
 
 	quit    chan struct{}
@@ -84,13 +91,24 @@ type ChainManager struct {
 }
 
 func NewChainManager(chainDb common.Database, pow pow.PoW, mux *event.TypeMux) (*ChainManager, error) {
-	cache, _ := lru.New(blockCacheLimit)
+	headerCache, _ := lru.New(headerCacheLimit)
+	bodyCache, _ := lru.New(bodyCacheLimit)
+	bodyRLPCache, _ := lru.New(bodyCacheLimit)
+	tdCache, _ := lru.New(tdCacheLimit)
+	blockCache, _ := lru.New(blockCacheLimit)
+	futureBlocks, _ := lru.New(maxFutureBlocks)
+
 	bc := &ChainManager{
-		chainDb:  chainDb,
-		eventMux: mux,
-		quit:     make(chan struct{}),
-		cache:    cache,
-		pow:      pow,
+		chainDb:      chainDb,
+		eventMux:     mux,
+		quit:         make(chan struct{}),
+		headerCache:  headerCache,
+		bodyCache:    bodyCache,
+		bodyRLPCache: bodyRLPCache,
+		tdCache:      tdCache,
+		blockCache:   blockCache,
+		futureBlocks: futureBlocks,
+		pow:          pow,
 	}
 
 	bc.genesisBlock = bc.GetBlockByNumber(0)
@@ -105,11 +123,9 @@ func NewChainManager(chainDb common.Database, pow pow.PoW, mux *event.TypeMux) (
 		}
 		glog.V(logger.Info).Infoln("WARNING: Wrote default ethereum genesis block")
 	}
-
 	if err := bc.setLastState(); err != nil {
 		return nil, err
 	}
-
 	// 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 block := bc.GetBlock(hash); block != nil {
@@ -123,14 +139,8 @@ func NewChainManager(chainDb common.Database, pow pow.PoW, mux *event.TypeMux) (
 			glog.V(logger.Error).Infoln("Chain reorg was successfull. Resuming normal operation")
 		}
 	}
-
 	// Take ownership of this particular state
-
-	bc.futureBlocks, _ = lru.New(maxFutureBlocks)
-	bc.makeCache()
-
 	go bc.update()
-
 	return bc, nil
 }
 
@@ -139,14 +149,16 @@ func (bc *ChainManager) SetHead(head *types.Block) {
 	defer bc.mu.Unlock()
 
 	for block := bc.currentBlock; block != nil && block.Hash() != head.Hash(); block = bc.GetBlock(block.ParentHash()) {
-		bc.removeBlock(block)
+		DeleteBlock(bc.chainDb, block.Hash())
 	}
+	bc.headerCache.Purge()
+	bc.bodyCache.Purge()
+	bc.bodyRLPCache.Purge()
+	bc.blockCache.Purge()
+	bc.futureBlocks.Purge()
 
-	bc.cache, _ = lru.New(blockCacheLimit)
 	bc.currentBlock = head
-	bc.makeCache()
-
-	bc.setTotalDifficulty(head.Td)
+	bc.setTotalDifficulty(bc.GetTd(head.Hash()))
 	bc.insert(head)
 	bc.setLastState()
 }
@@ -169,7 +181,7 @@ func (self *ChainManager) LastBlockHash() common.Hash {
 	self.mu.RLock()
 	defer self.mu.RUnlock()
 
-	return self.lastBlockHash
+	return self.currentBlock.Hash()
 }
 
 func (self *ChainManager) CurrentBlock() *types.Block {
@@ -199,13 +211,13 @@ func (bc *ChainManager) recover() bool {
 	if len(data) != 0 {
 		block := bc.GetBlock(common.BytesToHash(data))
 		if block != nil {
-			err := bc.chainDb.Put([]byte("LastBlock"), block.Hash().Bytes())
-			if err != nil {
-				glog.Fatalln("db write err:", err)
+			if err := WriteCanonicalHash(bc.chainDb, block.Hash(), block.NumberU64()); err != nil {
+				glog.Fatalf("failed to write database head number: %v", err)
+			}
+			if err := WriteHeadBlockHash(bc.chainDb, block.Hash()); err != nil {
+				glog.Fatalf("failed to write database head hash: %v", err)
 			}
-
 			bc.currentBlock = block
-			bc.lastBlockHash = block.Hash()
 			return true
 		}
 	}
@@ -213,14 +225,13 @@ func (bc *ChainManager) recover() bool {
 }
 
 func (bc *ChainManager) setLastState() error {
-	data, _ := bc.chainDb.Get([]byte("LastBlock"))
-	if len(data) != 0 {
-		block := bc.GetBlock(common.BytesToHash(data))
+	head := GetHeadBlockHash(bc.chainDb)
+	if head != (common.Hash{}) {
+		block := bc.GetBlock(head)
 		if block != nil {
 			bc.currentBlock = block
-			bc.lastBlockHash = block.Hash()
 		} else {
-			glog.Infof("LastBlock (%x) not found. Recovering...\n", data)
+			glog.Infof("LastBlock (%x) not found. Recovering...\n", head)
 			if bc.recover() {
 				glog.Infof("Recover successful")
 			} else {
@@ -230,7 +241,7 @@ func (bc *ChainManager) setLastState() error {
 	} else {
 		bc.Reset()
 	}
-	bc.td = bc.currentBlock.Td
+	bc.td = bc.GetTd(bc.currentBlock.Hash())
 	bc.currentGasLimit = CalcGasLimit(bc.currentBlock)
 
 	if glog.V(logger.Info) {
@@ -240,63 +251,37 @@ func (bc *ChainManager) setLastState() error {
 	return nil
 }
 
-func (bc *ChainManager) makeCache() {
-	bc.cache, _ = lru.New(blockCacheLimit)
-	// load in last `blockCacheLimit` - 1 blocks. Last block is the current.
-	bc.cache.Add(bc.genesisBlock.Hash(), bc.genesisBlock)
-	for _, block := range bc.GetBlocksFromHash(bc.currentBlock.Hash(), blockCacheLimit) {
-		bc.cache.Add(block.Hash(), block)
-	}
-}
-
+// Reset purges the entire blockchain, restoring it to its genesis state.
 func (bc *ChainManager) Reset() {
-	bc.mu.Lock()
-	defer bc.mu.Unlock()
-
-	for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.ParentHash()) {
-		bc.removeBlock(block)
-	}
-
-	bc.cache, _ = lru.New(blockCacheLimit)
-
-	// Prepare the genesis block
-	err := WriteBlock(bc.chainDb, bc.genesisBlock)
-	if err != nil {
-		glog.Fatalln("db err:", err)
-	}
-
-	bc.insert(bc.genesisBlock)
-	bc.currentBlock = bc.genesisBlock
-	bc.makeCache()
-
-	bc.setTotalDifficulty(common.Big("0"))
+	bc.ResetWithGenesisBlock(bc.genesisBlock)
 }
 
-func (bc *ChainManager) removeBlock(block *types.Block) {
-	bc.chainDb.Delete(append(blockHashPre, block.Hash().Bytes()...))
-}
-
-func (bc *ChainManager) ResetWithGenesisBlock(gb *types.Block) {
+// ResetWithGenesisBlock purges the entire blockchain, restoring it to the
+// specified genesis state.
+func (bc *ChainManager) ResetWithGenesisBlock(genesis *types.Block) {
 	bc.mu.Lock()
 	defer bc.mu.Unlock()
 
+	// Dump the entire block chain and purge the caches
 	for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.ParentHash()) {
-		bc.removeBlock(block)
+		DeleteBlock(bc.chainDb, block.Hash())
 	}
+	bc.headerCache.Purge()
+	bc.bodyCache.Purge()
+	bc.bodyRLPCache.Purge()
+	bc.blockCache.Purge()
+	bc.futureBlocks.Purge()
 
-	// Prepare the genesis block
-	gb.Td = gb.Difficulty()
-	bc.genesisBlock = gb
-
-	err := WriteBlock(bc.chainDb, bc.genesisBlock)
-	if err != nil {
-		glog.Fatalln("db err:", err)
+	// Prepare the genesis block and reinitialize the chain
+	if err := WriteTd(bc.chainDb, genesis.Hash(), genesis.Difficulty()); err != nil {
+		glog.Fatalf("failed to write genesis block TD: %v", err)
+	}
+	if err := WriteBlock(bc.chainDb, genesis); err != nil {
+		glog.Fatalf("failed to write genesis block: %v", err)
 	}
-
 	bc.insert(bc.genesisBlock)
 	bc.currentBlock = bc.genesisBlock
-	bc.makeCache()
-	bc.td = gb.Difficulty()
+	bc.setTotalDifficulty(genesis.Difficulty())
 }
 
 // Export writes the active chain to the given writer.
@@ -335,23 +320,23 @@ func (self *ChainManager) ExportN(w io.Writer, first uint64, last uint64) error
 // insert injects a block into the current chain block chain. Note, this function
 // assumes that the `mu` mutex is held!
 func (bc *ChainManager) insert(block *types.Block) {
-	err := WriteHead(bc.chainDb, block)
-	if err != nil {
-		glog.Fatal("db write fail:", err)
+	// Add the block to the canonical chain number scheme and mark as the head
+	if err := WriteCanonicalHash(bc.chainDb, block.Hash(), block.NumberU64()); err != nil {
+		glog.Fatalf("failed to insert block number: %v", err)
 	}
-
+	if err := WriteHeadBlockHash(bc.chainDb, block.Hash()); err != nil {
+		glog.Fatalf("failed to insert block number: %v", err)
+	}
+	// Add a new restore point if we reached some limit
 	bc.checkpoint++
 	if bc.checkpoint > checkpointLimit {
-		err = bc.chainDb.Put([]byte("checkpoint"), block.Hash().Bytes())
-		if err != nil {
-			glog.Fatal("db write fail:", err)
+		if err := bc.chainDb.Put([]byte("checkpoint"), block.Hash().Bytes()); err != nil {
+			glog.Fatalf("failed to create checkpoint: %v", err)
 		}
-
 		bc.checkpoint = 0
 	}
-
+	// Update the internal internal state with the head block
 	bc.currentBlock = block
-	bc.lastBlockHash = block.Hash()
 }
 
 // Accessors
@@ -359,61 +344,141 @@ func (bc *ChainManager) Genesis() *types.Block {
 	return bc.genesisBlock
 }
 
-// Block fetching methods
-func (bc *ChainManager) HasBlock(hash common.Hash) bool {
-	if bc.cache.Contains(hash) {
-		return true
+// HasHeader checks if a block header is present in the database or not, caching
+// it if present.
+func (bc *ChainManager) HasHeader(hash common.Hash) bool {
+	return bc.GetHeader(hash) != nil
+}
+
+// GetHeader retrieves a block header from the database by hash, caching it if
+// found.
+func (self *ChainManager) GetHeader(hash common.Hash) *types.Header {
+	// Short circuit if the header's already in the cache, retrieve otherwise
+	if header, ok := self.headerCache.Get(hash); ok {
+		return header.(*types.Header)
+	}
+	header := GetHeader(self.chainDb, hash)
+	if header == nil {
+		return nil
 	}
+	// Cache the found header for next time and return
+	self.headerCache.Add(header.Hash(), header)
+	return header
+}
 
-	data, _ := bc.chainDb.Get(append(blockHashPre, hash[:]...))
-	return len(data) != 0
+// GetHeaderByNumber retrieves a block header from the database by number,
+// caching it (associated with its hash) if found.
+func (self *ChainManager) GetHeaderByNumber(number uint64) *types.Header {
+	hash := GetCanonicalHash(self.chainDb, number)
+	if hash == (common.Hash{}) {
+		return nil
+	}
+	return self.GetHeader(hash)
 }
 
-func (self *ChainManager) GetBlockHashesFromHash(hash common.Hash, max uint64) (chain []common.Hash) {
-	block := self.GetBlock(hash)
-	if block == nil {
-		return
+// GetBody retrieves a block body (transactions and uncles) from the database by
+// hash, caching it if found.
+func (self *ChainManager) GetBody(hash common.Hash) *types.Body {
+	// Short circuit if the body's already in the cache, retrieve otherwise
+	if cached, ok := self.bodyCache.Get(hash); ok {
+		body := cached.(*types.Body)
+		return body
 	}
-	// XXX Could be optimised by using a different database which only holds hashes (i.e., linked list)
-	for i := uint64(0); i < max; i++ {
-		block = self.GetBlock(block.ParentHash())
-		if block == nil {
-			break
-		}
+	body := GetBody(self.chainDb, hash)
+	if body == nil {
+		return nil
+	}
+	// Cache the found body for next time and return
+	self.bodyCache.Add(hash, body)
+	return body
+}
 
-		chain = append(chain, block.Hash())
-		if block.Number().Cmp(common.Big0) <= 0 {
-			break
-		}
+// GetBodyRLP retrieves a block body in RLP encoding from the database by hash,
+// caching it if found.
+func (self *ChainManager) GetBodyRLP(hash common.Hash) rlp.RawValue {
+	// Short circuit if the body's already in the cache, retrieve otherwise
+	if cached, ok := self.bodyRLPCache.Get(hash); ok {
+		return cached.(rlp.RawValue)
 	}
+	body := GetBodyRLP(self.chainDb, hash)
+	if len(body) == 0 {
+		return nil
+	}
+	// Cache the found body for next time and return
+	self.bodyRLPCache.Add(hash, body)
+	return body
+}
 
-	return
+// GetTd retrieves a block's total difficulty in the canonical chain from the
+// database by hash, caching it if found.
+func (self *ChainManager) GetTd(hash common.Hash) *big.Int {
+	// Short circuit if the td's already in the cache, retrieve otherwise
+	if cached, ok := self.tdCache.Get(hash); ok {
+		return cached.(*big.Int)
+	}
+	td := GetTd(self.chainDb, hash)
+	if td == nil {
+		return nil
+	}
+	// Cache the found body for next time and return
+	self.tdCache.Add(hash, td)
+	return td
+}
+
+// HasBlock checks if a block is fully present in the database or not, caching
+// it if present.
+func (bc *ChainManager) HasBlock(hash common.Hash) bool {
+	return bc.GetBlock(hash) != nil
 }
 
+// GetBlock retrieves a block from the database by hash, caching it if found.
 func (self *ChainManager) GetBlock(hash common.Hash) *types.Block {
-	if block, ok := self.cache.Get(hash); ok {
+	// Short circuit if the block's already in the cache, retrieve otherwise
+	if block, ok := self.blockCache.Get(hash); ok {
 		return block.(*types.Block)
 	}
-
-	block := GetBlockByHash(self.chainDb, hash)
+	block := GetBlock(self.chainDb, hash)
 	if block == nil {
 		return nil
 	}
-
-	// Add the block to the cache
-	self.cache.Add(hash, (*types.Block)(block))
-
-	return (*types.Block)(block)
+	// Cache the found block for next time and return
+	self.blockCache.Add(block.Hash(), block)
+	return block
 }
 
-func (self *ChainManager) GetBlockByNumber(num uint64) *types.Block {
-	self.mu.RLock()
-	defer self.mu.RUnlock()
-
-	return self.getBlockByNumber(num)
+// GetBlockByNumber retrieves a block from the database by number, caching it
+// (associated with its hash) if found.
+func (self *ChainManager) GetBlockByNumber(number uint64) *types.Block {
+	hash := GetCanonicalHash(self.chainDb, number)
+	if hash == (common.Hash{}) {
+		return nil
+	}
+	return self.GetBlock(hash)
+}
 
+// GetBlockHashesFromHash retrieves a number of block hashes starting at a given
+// hash, fetching towards the genesis block.
+func (self *ChainManager) GetBlockHashesFromHash(hash common.Hash, max uint64) []common.Hash {
+	// Get the origin header from which to fetch
+	header := self.GetHeader(hash)
+	if header == nil {
+		return nil
+	}
+	// Iterate the headers until enough is collected or the genesis reached
+	chain := make([]common.Hash, 0, max)
+	for i := uint64(0); i < max; i++ {
+		if header = self.GetHeader(header.ParentHash); header == nil {
+			break
+		}
+		chain = append(chain, header.Hash())
+		if header.Number.Cmp(common.Big0) == 0 {
+			break
+		}
+	}
+	return chain
 }
 
+// [deprecated by eth/62]
 // GetBlocksFromHash returns the block corresponding to hash and up to n-1 ancestors.
 func (self *ChainManager) GetBlocksFromHash(hash common.Hash, n int) (blocks []*types.Block) {
 	for i := 0; i < n; i++ {
@@ -427,11 +492,6 @@ func (self *ChainManager) GetBlocksFromHash(hash common.Hash, n int) (blocks []*
 	return
 }
 
-// non blocking version
-func (self *ChainManager) getBlockByNumber(num uint64) *types.Block {
-	return GetBlockByNumber(self.chainDb, num)
-}
-
 func (self *ChainManager) GetUnclesInChain(block *types.Block, length int) (uncles []*types.Header) {
 	for i := 0; block != nil && i < length; i++ {
 		uncles = append(uncles, block.Uncles()...)
@@ -487,15 +547,25 @@ const (
 	SideStatTy
 )
 
-// WriteBlock writes the block to the chain (or pending queue)
-func (self *ChainManager) WriteBlock(block *types.Block, queued bool) (status writeStatus, err error) {
+// WriteBlock writes the block to the chain.
+func (self *ChainManager) WriteBlock(block *types.Block) (status writeStatus, err error) {
 	self.wg.Add(1)
 	defer self.wg.Done()
 
+	// Calculate the total difficulty of the block
+	ptd := self.GetTd(block.ParentHash())
+	if ptd == nil {
+		return NonStatTy, ParentError(block.ParentHash())
+	}
+	td := new(big.Int).Add(block.Difficulty(), ptd)
+
+	self.mu.RLock()
 	cblock := self.currentBlock
+	self.mu.RUnlock()
+
 	// Compare the TD of the last known block in the canonical chain to make sure it's greater.
 	// At this point it's possible that a different chain (fork) becomes the new canonical chain.
-	if block.Td.Cmp(self.Td()) > 0 {
+	if td.Cmp(self.Td()) > 0 {
 		// chain fork
 		if block.ParentHash() != cblock.Hash() {
 			// during split we merge two different chains and create the new canonical chain
@@ -503,12 +573,10 @@ func (self *ChainManager) WriteBlock(block *types.Block, queued bool) (status wr
 			if err != nil {
 				return NonStatTy, err
 			}
-
 			status = SplitStatTy
 		}
-
 		self.mu.Lock()
-		self.setTotalDifficulty(block.Td)
+		self.setTotalDifficulty(td)
 		self.insert(block)
 		self.mu.Unlock()
 
@@ -517,9 +585,11 @@ func (self *ChainManager) WriteBlock(block *types.Block, queued bool) (status wr
 		status = SideStatTy
 	}
 
-	err = WriteBlock(self.chainDb, block)
-	if err != nil {
-		glog.Fatalln("db err:", err)
+	if err := WriteTd(self.chainDb, block.Hash(), td); err != nil {
+		glog.Fatalf("failed to write block total difficulty: %v", err)
+	}
+	if err := WriteBlock(self.chainDb, block); err != nil {
+		glog.Fatalf("filed to write block contents: %v", err)
 	}
 	// Delete from future blocks
 	self.futureBlocks.Remove(block.Hash())
@@ -578,11 +648,6 @@ func (self *ChainManager) InsertChain(chain types.Blocks) (int, error) {
 			blockErr(block, err)
 			return i, err
 		}
-
-		// Setting block.Td regardless of error (known for example) prevents errors down the line
-		// in the protocol handler
-		block.Td = new(big.Int).Set(CalcTD(block, self.GetBlock(block.ParentHash())))
-
 		// Call in to the block processor and check for errors. It's likely that if one block fails
 		// all others will fail too (unless a known block is returned).
 		logs, receipts, err := self.processor.Process(block)
@@ -622,7 +687,7 @@ func (self *ChainManager) InsertChain(chain types.Blocks) (int, error) {
 		txcount += len(block.Transactions())
 
 		// write the block to the chain and get the status
-		status, err := self.WriteBlock(block, true)
+		status, err := self.WriteBlock(block)
 		if err != nil {
 			return i, err
 		}
@@ -755,12 +820,11 @@ out:
 					case ChainEvent:
 						// We need some control over the mining operation. Acquiring locks and waiting for the miner to create new block takes too long
 						// and in most cases isn't even necessary.
-						if self.lastBlockHash == event.Hash {
+						if self.currentBlock.Hash() == event.Hash {
 							self.currentGasLimit = CalcGasLimit(event.Block)
 							self.eventMux.Post(ChainHeadEvent{event.Block})
 						}
 					}
-
 					self.eventMux.Post(event)
 				}
 			}
diff --git a/core/chain_manager_test.go b/core/chain_manager_test.go
index 002dcbe44..a20480de8 100644
--- a/core/chain_manager_test.go
+++ b/core/chain_manager_test.go
@@ -77,6 +77,7 @@ func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big
 	bi1 := bman.bc.GetBlockByNumber(uint64(i)).Hash()
 	bi2 := bman2.bc.GetBlockByNumber(uint64(i)).Hash()
 	if bi1 != bi2 {
+		fmt.Printf("%+v\n%+v\n\n", bi1, bi2)
 		t.Fatal("chains do not have the same hash at height", i)
 	}
 	bman2.bc.SetProcessor(bman2)
@@ -110,7 +111,6 @@ func printChain(bc *ChainManager) {
 
 // process blocks against a chain
 func testChain(chainB types.Blocks, bman *BlockProcessor) (*big.Int, error) {
-	td := new(big.Int)
 	for _, block := range chainB {
 		_, _, err := bman.bc.processor.Process(block)
 		if err != nil {
@@ -119,17 +119,12 @@ func testChain(chainB types.Blocks, bman *BlockProcessor) (*big.Int, error) {
 			}
 			return nil, err
 		}
-		parent := bman.bc.GetBlock(block.ParentHash())
-		block.Td = CalcTD(block, parent)
-		td = block.Td
-
 		bman.bc.mu.Lock()
-		{
-			WriteBlock(bman.bc.chainDb, block)
-		}
+		WriteTd(bman.bc.chainDb, block.Hash(), new(big.Int).Add(block.Difficulty(), bman.bc.GetTd(block.ParentHash())))
+		WriteBlock(bman.bc.chainDb, block)
 		bman.bc.mu.Unlock()
 	}
-	return td, nil
+	return bman.bc.GetTd(chainB[len(chainB)-1].Hash()), nil
 }
 
 func loadChain(fn string, t *testing.T) (types.Blocks, error) {
@@ -388,7 +383,11 @@ func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block
 func chm(genesis *types.Block, db common.Database) *ChainManager {
 	var eventMux event.TypeMux
 	bc := &ChainManager{chainDb: db, genesisBlock: genesis, eventMux: &eventMux, pow: FakePow{}}
-	bc.cache, _ = lru.New(100)
+	bc.headerCache, _ = lru.New(100)
+	bc.bodyCache, _ = lru.New(100)
+	bc.bodyRLPCache, _ = lru.New(100)
+	bc.tdCache, _ = lru.New(100)
+	bc.blockCache, _ = lru.New(100)
 	bc.futureBlocks, _ = lru.New(100)
 	bc.processor = bproc{}
 	bc.ResetWithGenesisBlock(genesis)
diff --git a/core/chain_util.go b/core/chain_util.go
index 84b462ce3..0e3fa31f9 100644
--- a/core/chain_util.go
+++ b/core/chain_util.go
@@ -19,7 +19,6 @@ package core
 import (
 	"bytes"
 	"math/big"
-	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -30,9 +29,18 @@ import (
 )
 
 var (
-	blockHashPre  = []byte("block-hash-")
-	blockNumPre   = []byte("block-num-")
+	headHeaderKey = []byte("LastHeader")
+	headBlockKey  = []byte("LastBlock")
+
+	blockPrefix    = []byte("block-")
+	blockNumPrefix = []byte("block-num-")
+
+	headerSuffix = []byte("-header")
+	bodySuffix   = []byte("-body")
+	tdSuffix     = []byte("-td")
+
 	ExpDiffPeriod = big.NewInt(100000)
+	blockHashPre  = []byte("block-hash-") // [deprecated by eth/63]
 )
 
 // CalcDifficulty is the difficulty adjustment algorithm. It returns
@@ -69,16 +77,6 @@ func CalcDifficulty(time, parentTime uint64, parentNumber, parentDiff *big.Int)
 	return diff
 }
 
-// CalcTD computes the total difficulty of block.
-func CalcTD(block, parent *types.Block) *big.Int {
-	if parent == nil {
-		return block.Difficulty()
-	}
-	d := block.Difficulty()
-	d.Add(d, parent.Td)
-	return d
-}
-
 // CalcGasLimit computes the gas limit of the next block after parent.
 // The result may be modified by the caller.
 // This is miner strategy, not consensus protocol.
@@ -112,68 +110,238 @@ func CalcGasLimit(parent *types.Block) *big.Int {
 	return gl
 }
 
-// GetBlockByHash returns the block corresponding to the hash or nil if not found
-func GetBlockByHash(db common.Database, hash common.Hash) *types.Block {
-	data, _ := db.Get(append(blockHashPre, hash[:]...))
+// GetCanonicalHash retrieves a hash assigned to a canonical block number.
+func GetCanonicalHash(db common.Database, number uint64) common.Hash {
+	data, _ := db.Get(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))
+	if len(data) == 0 {
+		return common.Hash{}
+	}
+	return common.BytesToHash(data)
+}
+
+// GetHeadHeaderHash retrieves the hash of the current canonical head block's
+// header. The difference between this and GetHeadBlockHash is that whereas the
+// last block hash is only updated upon a full block import, the last header
+// hash is updated already at header import, allowing head tracking for the
+// fast synchronization mechanism.
+func GetHeadHeaderHash(db common.Database) common.Hash {
+	data, _ := db.Get(headHeaderKey)
+	if len(data) == 0 {
+		return common.Hash{}
+	}
+	return common.BytesToHash(data)
+}
+
+// GetHeadBlockHash retrieves the hash of the current canonical head block.
+func GetHeadBlockHash(db common.Database) common.Hash {
+	data, _ := db.Get(headBlockKey)
+	if len(data) == 0 {
+		return common.Hash{}
+	}
+	return common.BytesToHash(data)
+}
+
+// GetHeaderRLP retrieves a block header in its raw RLP database encoding, or nil
+// if the header's not found.
+func GetHeaderRLP(db common.Database, hash common.Hash) rlp.RawValue {
+	data, _ := db.Get(append(append(blockPrefix, hash[:]...), headerSuffix...))
+	return data
+}
+
+// GetHeader retrieves the block header corresponding to the hash, nil if none
+// found.
+func GetHeader(db common.Database, hash common.Hash) *types.Header {
+	data := GetHeaderRLP(db, hash)
 	if len(data) == 0 {
 		return nil
 	}
-	var block types.StorageBlock
-	if err := rlp.Decode(bytes.NewReader(data), &block); err != nil {
-		glog.V(logger.Error).Infof("invalid block RLP for hash %x: %v", hash, err)
+	header := new(types.Header)
+	if err := rlp.Decode(bytes.NewReader(data), header); err != nil {
+		glog.V(logger.Error).Infof("invalid block header RLP for hash %x: %v", hash, err)
 		return nil
 	}
-	return (*types.Block)(&block)
+	return header
+}
+
+// GetBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
+func GetBodyRLP(db common.Database, hash common.Hash) rlp.RawValue {
+	data, _ := db.Get(append(append(blockPrefix, hash[:]...), bodySuffix...))
+	return data
 }
 
-// GetBlockByHash returns the canonical block by number or nil if not found
-func GetBlockByNumber(db common.Database, number uint64) *types.Block {
-	key, _ := db.Get(append(blockNumPre, big.NewInt(int64(number)).Bytes()...))
-	if len(key) == 0 {
+// GetBody retrieves the block body (transactons, uncles) corresponding to the
+// hash, nil if none found.
+func GetBody(db common.Database, hash common.Hash) *types.Body {
+	data := GetBodyRLP(db, hash)
+	if len(data) == 0 {
+		return nil
+	}
+	body := new(types.Body)
+	if err := rlp.Decode(bytes.NewReader(data), body); err != nil {
+		glog.V(logger.Error).Infof("invalid block body RLP for hash %x: %v", hash, err)
 		return nil
 	}
+	return body
+}
 
-	return GetBlockByHash(db, common.BytesToHash(key))
+// GetTd retrieves a block's total difficulty corresponding to the hash, nil if
+// none found.
+func GetTd(db common.Database, hash common.Hash) *big.Int {
+	data, _ := db.Get(append(append(blockPrefix, hash.Bytes()...), tdSuffix...))
+	if len(data) == 0 {
+		return nil
+	}
+	td := new(big.Int)
+	if err := rlp.Decode(bytes.NewReader(data), td); err != nil {
+		glog.V(logger.Error).Infof("invalid block total difficulty RLP for hash %x: %v", hash, err)
+		return nil
+	}
+	return td
 }
 
-// WriteCanonNumber writes the canonical hash for the given block
-func WriteCanonNumber(db common.Database, block *types.Block) error {
-	key := append(blockNumPre, block.Number().Bytes()...)
-	err := db.Put(key, block.Hash().Bytes())
-	if err != nil {
+// GetBlock retrieves an entire block corresponding to the hash, assembling it
+// back from the stored header and body.
+func GetBlock(db common.Database, hash common.Hash) *types.Block {
+	// Retrieve the block header and body contents
+	header := GetHeader(db, hash)
+	if header == nil {
+		return nil
+	}
+	body := GetBody(db, hash)
+	if body == nil {
+		return nil
+	}
+	// Reassemble the block and return
+	return types.NewBlockWithHeader(header).WithBody(body.Transactions, body.Uncles)
+}
+
+// WriteCanonicalHash stores the canonical hash for the given block number.
+func WriteCanonicalHash(db common.Database, hash common.Hash, number uint64) error {
+	key := append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...)
+	if err := db.Put(key, hash.Bytes()); err != nil {
+		glog.Fatalf("failed to store number to hash mapping into database: %v", err)
 		return err
 	}
 	return nil
 }
 
-// WriteHead force writes the current head
-func WriteHead(db common.Database, block *types.Block) error {
-	err := WriteCanonNumber(db, block)
-	if err != nil {
+// WriteHeadHeaderHash stores the head header's hash.
+func WriteHeadHeaderHash(db common.Database, hash common.Hash) error {
+	if err := db.Put(headHeaderKey, hash.Bytes()); err != nil {
+		glog.Fatalf("failed to store last header's hash into database: %v", err)
 		return err
 	}
-	err = db.Put([]byte("LastBlock"), block.Hash().Bytes())
-	if err != nil {
+	return nil
+}
+
+// WriteHeadBlockHash stores the head block's hash.
+func WriteHeadBlockHash(db common.Database, hash common.Hash) error {
+	if err := db.Put(headBlockKey, hash.Bytes()); err != nil {
+		glog.Fatalf("failed to store last block's hash into database: %v", err)
 		return err
 	}
 	return nil
 }
 
-// WriteBlock writes a block to the database
-func WriteBlock(db common.Database, block *types.Block) error {
-	tstart := time.Now()
+// WriteHeader serializes a block header into the database.
+func WriteHeader(db common.Database, header *types.Header) error {
+	data, err := rlp.EncodeToBytes(header)
+	if err != nil {
+		return err
+	}
+	key := append(append(blockPrefix, header.Hash().Bytes()...), headerSuffix...)
+	if err := db.Put(key, data); err != nil {
+		glog.Fatalf("failed to store header into database: %v", err)
+		return err
+	}
+	glog.V(logger.Debug).Infof("stored header #%v [%x…]", header.Number, header.Hash().Bytes()[:4])
+	return nil
+}
 
-	enc, _ := rlp.EncodeToBytes((*types.StorageBlock)(block))
-	key := append(blockHashPre, block.Hash().Bytes()...)
-	err := db.Put(key, enc)
+// WriteBody serializes the body of a block into the database.
+func WriteBody(db common.Database, hash common.Hash, body *types.Body) error {
+	data, err := rlp.EncodeToBytes(body)
 	if err != nil {
-		glog.Fatal("db write fail:", err)
 		return err
 	}
+	key := append(append(blockPrefix, hash.Bytes()...), bodySuffix...)
+	if err := db.Put(key, data); err != nil {
+		glog.Fatalf("failed to store block body into database: %v", err)
+		return err
+	}
+	glog.V(logger.Debug).Infof("stored block body [%x…]", hash.Bytes()[:4])
+	return nil
+}
 
-	if glog.V(logger.Debug) {
-		glog.Infof("wrote block #%v %s. Took %v\n", block.Number(), common.PP(block.Hash().Bytes()), time.Since(tstart))
+// WriteTd serializes the total difficulty of a block into the database.
+func WriteTd(db common.Database, hash common.Hash, td *big.Int) error {
+	data, err := rlp.EncodeToBytes(td)
+	if err != nil {
+		return err
 	}
+	key := append(append(blockPrefix, hash.Bytes()...), tdSuffix...)
+	if err := db.Put(key, data); err != nil {
+		glog.Fatalf("failed to store block total difficulty into database: %v", err)
+		return err
+	}
+	glog.V(logger.Debug).Infof("stored block total difficulty [%x…]: %v", hash.Bytes()[:4], td)
+	return nil
+}
 
+// WriteBlock serializes a block into the database, header and body separately.
+func WriteBlock(db common.Database, block *types.Block) error {
+	// Store the body first to retain database consistency
+	if err := WriteBody(db, block.Hash(), &types.Body{block.Transactions(), block.Uncles()}); err != nil {
+		return err
+	}
+	// Store the header too, signaling full block ownership
+	if err := WriteHeader(db, block.Header()); err != nil {
+		return err
+	}
 	return nil
 }
+
+// DeleteCanonicalHash removes the number to hash canonical mapping.
+func DeleteCanonicalHash(db common.Database, number uint64) {
+	db.Delete(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))
+}
+
+// DeleteHeader removes all block header data associated with a hash.
+func DeleteHeader(db common.Database, hash common.Hash) {
+	db.Delete(append(append(blockPrefix, hash.Bytes()...), headerSuffix...))
+}
+
+// DeleteBody removes all block body data associated with a hash.
+func DeleteBody(db common.Database, hash common.Hash) {
+	db.Delete(append(append(blockPrefix, hash.Bytes()...), bodySuffix...))
+}
+
+// DeleteTd removes all block total difficulty data associated with a hash.
+func DeleteTd(db common.Database, hash common.Hash) {
+	db.Delete(append(append(blockPrefix, hash.Bytes()...), tdSuffix...))
+}
+
+// DeleteBlock removes all block data associated with a hash.
+func DeleteBlock(db common.Database, hash common.Hash) {
+	DeleteHeader(db, hash)
+	DeleteBody(db, hash)
+	DeleteTd(db, hash)
+}
+
+// [deprecated by eth/63]
+// GetBlockByHashOld returns the old combined block corresponding to the hash
+// or nil if not found. This method is only used by the upgrade mechanism to
+// access the old combined block representation. It will be dropped after the
+// network transitions to eth/63.
+func GetBlockByHashOld(db common.Database, hash common.Hash) *types.Block {
+	data, _ := db.Get(append(blockHashPre, hash[:]...))
+	if len(data) == 0 {
+		return nil
+	}
+	var block types.StorageBlock
+	if err := rlp.Decode(bytes.NewReader(data), &block); err != nil {
+		glog.V(logger.Error).Infof("invalid block RLP for hash %x: %v", hash, err)
+		return nil
+	}
+	return (*types.Block)(&block)
+}
diff --git a/core/chain_util_test.go b/core/chain_util_test.go
index 4bbe81194..3f0446715 100644
--- a/core/chain_util_test.go
+++ b/core/chain_util_test.go
@@ -23,6 +23,10 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto/sha3"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 type diffTest struct {
@@ -75,3 +79,242 @@ func TestDifficulty(t *testing.T) {
 		}
 	}
 }
+
+// Tests block header storage and retrieval operations.
+func TestHeaderStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	// Create a test header to move around the database and make sure it's really new
+	header := &types.Header{Extra: []byte("test header")}
+	if entry := GetHeader(db, header.Hash()); entry != nil {
+		t.Fatalf("Non existent header returned: %v", entry)
+	}
+	// Write and verify the header in the database
+	if err := WriteHeader(db, header); err != nil {
+		t.Fatalf("Failed to write header into database: %v", err)
+	}
+	if entry := GetHeader(db, header.Hash()); entry == nil {
+		t.Fatalf("Stored header not found")
+	} else if entry.Hash() != header.Hash() {
+		t.Fatalf("Retrieved header mismatch: have %v, want %v", entry, header)
+	}
+	if entry := GetHeaderRLP(db, header.Hash()); entry == nil {
+		t.Fatalf("Stored header RLP not found")
+	} else {
+		hasher := sha3.NewKeccak256()
+		hasher.Write(entry)
+
+		if hash := common.BytesToHash(hasher.Sum(nil)); hash != header.Hash() {
+			t.Fatalf("Retrieved RLP header mismatch: have %v, want %v", entry, header)
+		}
+	}
+	// Delete the header and verify the execution
+	DeleteHeader(db, header.Hash())
+	if entry := GetHeader(db, header.Hash()); entry != nil {
+		t.Fatalf("Deleted header returned: %v", entry)
+	}
+}
+
+// Tests block body storage and retrieval operations.
+func TestBodyStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	// Create a test body to move around the database and make sure it's really new
+	body := &types.Body{Uncles: []*types.Header{{Extra: []byte("test header")}}}
+
+	hasher := sha3.NewKeccak256()
+	rlp.Encode(hasher, body)
+	hash := common.BytesToHash(hasher.Sum(nil))
+
+	if entry := GetBody(db, hash); entry != nil {
+		t.Fatalf("Non existent body returned: %v", entry)
+	}
+	// Write and verify the body in the database
+	if err := WriteBody(db, hash, body); err != nil {
+		t.Fatalf("Failed to write body into database: %v", err)
+	}
+	if entry := GetBody(db, hash); entry == nil {
+		t.Fatalf("Stored body not found")
+	} else if types.DeriveSha(types.Transactions(entry.Transactions)) != types.DeriveSha(types.Transactions(body.Transactions)) || types.CalcUncleHash(entry.Uncles) != types.CalcUncleHash(body.Uncles) {
+		t.Fatalf("Retrieved body mismatch: have %v, want %v", entry, body)
+	}
+	if entry := GetBodyRLP(db, hash); entry == nil {
+		t.Fatalf("Stored body RLP not found")
+	} else {
+		hasher := sha3.NewKeccak256()
+		hasher.Write(entry)
+
+		if calc := common.BytesToHash(hasher.Sum(nil)); calc != hash {
+			t.Fatalf("Retrieved RLP body mismatch: have %v, want %v", entry, body)
+		}
+	}
+	// Delete the body and verify the execution
+	DeleteBody(db, hash)
+	if entry := GetBody(db, hash); entry != nil {
+		t.Fatalf("Deleted body returned: %v", entry)
+	}
+}
+
+// Tests block storage and retrieval operations.
+func TestBlockStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	// Create a test block to move around the database and make sure it's really new
+	block := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block")})
+	if entry := GetBlock(db, block.Hash()); entry != nil {
+		t.Fatalf("Non existent block returned: %v", entry)
+	}
+	if entry := GetHeader(db, block.Hash()); entry != nil {
+		t.Fatalf("Non existent header returned: %v", entry)
+	}
+	if entry := GetBody(db, block.Hash()); entry != nil {
+		t.Fatalf("Non existent body returned: %v", entry)
+	}
+	// Write and verify the block in the database
+	if err := WriteBlock(db, block); err != nil {
+		t.Fatalf("Failed to write block into database: %v", err)
+	}
+	if entry := GetBlock(db, block.Hash()); entry == nil {
+		t.Fatalf("Stored block not found")
+	} else if entry.Hash() != block.Hash() {
+		t.Fatalf("Retrieved block mismatch: have %v, want %v", entry, block)
+	}
+	if entry := GetHeader(db, block.Hash()); entry == nil {
+		t.Fatalf("Stored header not found")
+	} else if entry.Hash() != block.Header().Hash() {
+		t.Fatalf("Retrieved header mismatch: have %v, want %v", entry, block.Header())
+	}
+	if entry := GetBody(db, block.Hash()); entry == nil {
+		t.Fatalf("Stored body not found")
+	} else if types.DeriveSha(types.Transactions(entry.Transactions)) != types.DeriveSha(block.Transactions()) || types.CalcUncleHash(entry.Uncles) != types.CalcUncleHash(block.Uncles()) {
+		t.Fatalf("Retrieved body mismatch: have %v, want %v", entry, &types.Body{block.Transactions(), block.Uncles()})
+	}
+	// Delete the block and verify the execution
+	DeleteBlock(db, block.Hash())
+	if entry := GetBlock(db, block.Hash()); entry != nil {
+		t.Fatalf("Deleted block returned: %v", entry)
+	}
+	if entry := GetHeader(db, block.Hash()); entry != nil {
+		t.Fatalf("Deleted header returned: %v", entry)
+	}
+	if entry := GetBody(db, block.Hash()); entry != nil {
+		t.Fatalf("Deleted body returned: %v", entry)
+	}
+}
+
+// Tests that partial block contents don't get reassembled into full blocks.
+func TestPartialBlockStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+	block := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block")})
+
+	// Store a header and check that it's not recognized as a block
+	if err := WriteHeader(db, block.Header()); err != nil {
+		t.Fatalf("Failed to write header into database: %v", err)
+	}
+	if entry := GetBlock(db, block.Hash()); entry != nil {
+		t.Fatalf("Non existent block returned: %v", entry)
+	}
+	DeleteHeader(db, block.Hash())
+
+	// Store a body and check that it's not recognized as a block
+	if err := WriteBody(db, block.Hash(), &types.Body{block.Transactions(), block.Uncles()}); err != nil {
+		t.Fatalf("Failed to write body into database: %v", err)
+	}
+	if entry := GetBlock(db, block.Hash()); entry != nil {
+		t.Fatalf("Non existent block returned: %v", entry)
+	}
+	DeleteBody(db, block.Hash())
+
+	// Store a header and a body separately and check reassembly
+	if err := WriteHeader(db, block.Header()); err != nil {
+		t.Fatalf("Failed to write header into database: %v", err)
+	}
+	if err := WriteBody(db, block.Hash(), &types.Body{block.Transactions(), block.Uncles()}); err != nil {
+		t.Fatalf("Failed to write body into database: %v", err)
+	}
+	if entry := GetBlock(db, block.Hash()); entry == nil {
+		t.Fatalf("Stored block not found")
+	} else if entry.Hash() != block.Hash() {
+		t.Fatalf("Retrieved block mismatch: have %v, want %v", entry, block)
+	}
+}
+
+// Tests block total difficulty storage and retrieval operations.
+func TestTdStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	// Create a test TD to move around the database and make sure it's really new
+	hash, td := common.Hash{}, big.NewInt(314)
+	if entry := GetTd(db, hash); entry != nil {
+		t.Fatalf("Non existent TD returned: %v", entry)
+	}
+	// Write and verify the TD in the database
+	if err := WriteTd(db, hash, td); err != nil {
+		t.Fatalf("Failed to write TD into database: %v", err)
+	}
+	if entry := GetTd(db, hash); entry == nil {
+		t.Fatalf("Stored TD not found")
+	} else if entry.Cmp(td) != 0 {
+		t.Fatalf("Retrieved TD mismatch: have %v, want %v", entry, td)
+	}
+	// Delete the TD and verify the execution
+	DeleteTd(db, hash)
+	if entry := GetTd(db, hash); entry != nil {
+		t.Fatalf("Deleted TD returned: %v", entry)
+	}
+}
+
+// Tests that canonical numbers can be mapped to hashes and retrieved.
+func TestCanonicalMappingStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	// Create a test canonical number and assinged hash to move around
+	hash, number := common.Hash{0: 0xff}, uint64(314)
+	if entry := GetCanonicalHash(db, number); entry != (common.Hash{}) {
+		t.Fatalf("Non existent canonical mapping returned: %v", entry)
+	}
+	// Write and verify the TD in the database
+	if err := WriteCanonicalHash(db, hash, number); err != nil {
+		t.Fatalf("Failed to write canonical mapping into database: %v", err)
+	}
+	if entry := GetCanonicalHash(db, number); entry == (common.Hash{}) {
+		t.Fatalf("Stored canonical mapping not found")
+	} else if entry != hash {
+		t.Fatalf("Retrieved canonical mapping mismatch: have %v, want %v", entry, hash)
+	}
+	// Delete the TD and verify the execution
+	DeleteCanonicalHash(db, number)
+	if entry := GetCanonicalHash(db, number); entry != (common.Hash{}) {
+		t.Fatalf("Deleted canonical mapping returned: %v", entry)
+	}
+}
+
+// Tests that head headers and head blocks can be assigned, individually.
+func TestHeadStorage(t *testing.T) {
+	db, _ := ethdb.NewMemDatabase()
+
+	blockHead := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block header")})
+	blockFull := types.NewBlockWithHeader(&types.Header{Extra: []byte("test block full")})
+
+	// Check that no head entries are in a pristine database
+	if entry := GetHeadHeaderHash(db); entry != (common.Hash{}) {
+		t.Fatalf("Non head header entry returned: %v", entry)
+	}
+	if entry := GetHeadBlockHash(db); entry != (common.Hash{}) {
+		t.Fatalf("Non head block entry returned: %v", entry)
+	}
+	// Assign separate entries for the head header and block
+	if err := WriteHeadHeaderHash(db, blockHead.Hash()); err != nil {
+		t.Fatalf("Failed to write head header hash: %v", err)
+	}
+	if err := WriteHeadBlockHash(db, blockFull.Hash()); err != nil {
+		t.Fatalf("Failed to write head block hash: %v", err)
+	}
+	// Check that both heads are present, and different (i.e. two heads maintained)
+	if entry := GetHeadHeaderHash(db); entry != blockHead.Hash() {
+		t.Fatalf("Head header hash mismatch: have %v, want %v", entry, blockHead.Hash())
+	}
+	if entry := GetHeadBlockHash(db); entry != blockFull.Hash() {
+		t.Fatalf("Head block hash mismatch: have %v, want %v", entry, blockFull.Hash())
+	}
+}
diff --git a/core/genesis.go b/core/genesis.go
index 7d4e03c99..3a8f0af0c 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -82,28 +82,29 @@ func WriteGenesisBlock(chainDb common.Database, reader io.Reader) (*types.Block,
 		Coinbase:   common.HexToAddress(genesis.Coinbase),
 		Root:       statedb.Root(),
 	}, nil, nil, nil)
-	block.Td = difficulty
 
-	if block := GetBlockByHash(chainDb, block.Hash()); block != nil {
+	if block := GetBlock(chainDb, block.Hash()); block != nil {
 		glog.V(logger.Info).Infoln("Genesis block already in chain. Writing canonical number")
-		err := WriteCanonNumber(chainDb, block)
+		err := WriteCanonicalHash(chainDb, block.Hash(), block.NumberU64())
 		if err != nil {
 			return nil, err
 		}
 		return block, nil
 	}
-
 	statedb.Sync()
 
-	err = WriteBlock(chainDb, block)
-	if err != nil {
+	if err := WriteTd(chainDb, block.Hash(), difficulty); err != nil {
 		return nil, err
 	}
-	err = WriteHead(chainDb, block)
-	if err != nil {
+	if err := WriteBlock(chainDb, block); err != nil {
+		return nil, err
+	}
+	if err := WriteCanonicalHash(chainDb, block.Hash(), block.NumberU64()); err != nil {
+		return nil, err
+	}
+	if err := WriteHeadBlockHash(chainDb, block.Hash()); err != nil {
 		return nil, err
 	}
-
 	return block, nil
 }
 
@@ -120,7 +121,6 @@ func GenesisBlockForTesting(db common.Database, addr common.Address, balance *bi
 		GasLimit:   params.GenesisGasLimit,
 		Root:       statedb.Root(),
 	}, nil, nil, nil)
-	block.Td = params.GenesisDifficulty
 	return block
 }
 
diff --git a/core/types/block.go b/core/types/block.go
index fd81db04c..7a84045a6 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -117,6 +117,13 @@ func rlpHash(x interface{}) (h common.Hash) {
 	return h
 }
 
+// Body is a simple (mutable, non-safe) data container for storing and moving
+// a block's data contents (transactions and uncles) together.
+type Body struct {
+	Transactions []*Transaction
+	Uncles       []*Header
+}
+
 type Block struct {
 	header       *Header
 	uncles       []*Header
@@ -129,12 +136,20 @@ type Block struct {
 
 	// Td is used by package core to store the total difficulty
 	// of the chain up to and including the block.
-	Td *big.Int
+	td *big.Int
 
 	// ReceivedAt is used by package eth to track block propagation time.
 	ReceivedAt time.Time
 }
 
+// DeprecatedTd is an old relic for extracting the TD of a block. It is in the
+// code solely to facilitate upgrading the database from the old format to the
+// new, after which it should be deleted. Do not use!
+func (b *Block) DeprecatedTd() *big.Int {
+	return b.td
+}
+
+// [deprecated by eth/63]
 // StorageBlock defines the RLP encoding of a Block stored in the
 // state database. The StorageBlock encoding contains fields that
 // would otherwise need to be recomputed.
@@ -147,6 +162,7 @@ type extblock struct {
 	Uncles []*Header
 }
 
+// [deprecated by eth/63]
 // "storage" block encoding. used for database.
 type storageblock struct {
 	Header *Header
@@ -168,7 +184,7 @@ var (
 // are ignored and set to values derived from the given txs, uncles
 // and receipts.
 func NewBlock(header *Header, txs []*Transaction, uncles []*Header, receipts []*Receipt) *Block {
-	b := &Block{header: copyHeader(header), Td: new(big.Int)}
+	b := &Block{header: copyHeader(header), td: new(big.Int)}
 
 	// TODO: panic if len(txs) != len(receipts)
 	if len(txs) == 0 {
@@ -268,24 +284,16 @@ func (b *Block) EncodeRLP(w io.Writer) error {
 	})
 }
 
+// [deprecated by eth/63]
 func (b *StorageBlock) DecodeRLP(s *rlp.Stream) error {
 	var sb storageblock
 	if err := s.Decode(&sb); err != nil {
 		return err
 	}
-	b.header, b.uncles, b.transactions, b.Td = sb.Header, sb.Uncles, sb.Txs, sb.TD
+	b.header, b.uncles, b.transactions, b.td = sb.Header, sb.Uncles, sb.Txs, sb.TD
 	return nil
 }
 
-func (b *StorageBlock) EncodeRLP(w io.Writer) error {
-	return rlp.Encode(w, storageblock{
-		Header: b.header,
-		Txs:    b.transactions,
-		Uncles: b.uncles,
-		TD:     b.Td,
-	})
-}
-
 // TODO: copies
 func (b *Block) Uncles() []*Header          { return b.uncles }
 func (b *Block) Transactions() Transactions { return b.transactions }
@@ -356,7 +364,6 @@ func (b *Block) WithMiningResult(nonce uint64, mixDigest common.Hash) *Block {
 		transactions: b.transactions,
 		receipts:     b.receipts,
 		uncles:       b.uncles,
-		Td:           b.Td,
 	}
 }
 
@@ -386,7 +393,7 @@ func (b *Block) Hash() common.Hash {
 }
 
 func (b *Block) String() string {
-	str := fmt.Sprintf(`Block(#%v): Size: %v TD: %v {
+	str := fmt.Sprintf(`Block(#%v): Size: %v {
 MinerHash: %x
 %v
 Transactions:
@@ -394,7 +401,7 @@ Transactions:
 Uncles:
 %v
 }
-`, b.Number(), b.Size(), b.Td, b.header.HashNoNonce(), b.header, b.transactions, b.uncles)
+`, b.Number(), b.Size(), b.header.HashNoNonce(), b.header, b.transactions, b.uncles)
 	return str
 }
 
diff --git a/eth/backend.go b/eth/backend.go
index 639aaaaec..deb6d3d0f 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -18,6 +18,7 @@
 package eth
 
 import (
+	"bytes"
 	"crypto/ecdsa"
 	"encoding/json"
 	"fmt"
@@ -269,11 +270,7 @@ func New(config *Config) (*Ethereum, error) {
 		newdb = func(path string) (common.Database, error) { return ethdb.NewLDBDatabase(path, config.DatabaseCache) }
 	}
 
-	// attempt to merge database together, upgrading from an old version
-	if err := mergeDatabases(config.DataDir, newdb); err != nil {
-		return nil, err
-	}
-
+	// Open the chain database and perform any upgrades needed
 	chainDb, err := newdb(filepath.Join(config.DataDir, "chaindata"))
 	if err != nil {
 		return nil, fmt.Errorf("blockchain db err: %v", err)
@@ -281,6 +278,10 @@ func New(config *Config) (*Ethereum, error) {
 	if db, ok := chainDb.(*ethdb.LDBDatabase); ok {
 		db.Meter("eth/db/chaindata/")
 	}
+	if err := upgradeChainDatabase(chainDb); err != nil {
+		return nil, err
+	}
+
 	dappDb, err := newdb(filepath.Join(config.DataDir, "dapp"))
 	if err != nil {
 		return nil, fmt.Errorf("dapp db err: %v", err)
@@ -315,9 +316,13 @@ func New(config *Config) (*Ethereum, error) {
 		if err != nil {
 			return nil, err
 		}
-	case config.GenesisBlock != nil: // This is for testing only.
+	}
+	// This is for testing only.
+	if config.GenesisBlock != nil {
+		core.WriteTd(chainDb, config.GenesisBlock.Hash(), config.GenesisBlock.Difficulty())
 		core.WriteBlock(chainDb, config.GenesisBlock)
-		core.WriteHead(chainDb, config.GenesisBlock)
+		core.WriteCanonicalHash(chainDb, config.GenesisBlock.Hash(), config.GenesisBlock.NumberU64())
+		core.WriteHeadBlockHash(chainDb, config.GenesisBlock.Hash())
 	}
 
 	if !config.SkipBcVersionCheck {
@@ -721,74 +726,61 @@ func saveBlockchainVersion(db common.Database, bcVersion int) {
 	}
 }
 
-// mergeDatabases when required merge old database layout to one single database
-func mergeDatabases(datadir string, newdb func(path string) (common.Database, error)) error {
-	// Check if already upgraded
-	data := filepath.Join(datadir, "chaindata")
-	if _, err := os.Stat(data); !os.IsNotExist(err) {
-		return nil
-	}
-	// make sure it's not just a clean path
-	chainPath := filepath.Join(datadir, "blockchain")
-	if _, err := os.Stat(chainPath); os.IsNotExist(err) {
+// upgradeChainDatabase ensures that the chain database stores block split into
+// separate header and body entries.
+func upgradeChainDatabase(db common.Database) error {
+	// Short circuit if the head block is stored already as separate header and body
+	data, err := db.Get([]byte("LastBlock"))
+	if err != nil {
 		return nil
 	}
-	glog.Infoln("Database upgrade required. Upgrading...")
+	head := common.BytesToHash(data)
 
-	database, err := newdb(data)
-	if err != nil {
-		return fmt.Errorf("creating data db err: %v", err)
+	if block := core.GetBlockByHashOld(db, head); block == nil {
+		return nil
 	}
-	defer database.Close()
+	// At least some of the database is still the old format, upgrade (skip the head block!)
+	glog.V(logger.Info).Info("Old database detected, upgrading...")
 
-	// Migrate blocks
-	chainDb, err := newdb(chainPath)
-	if err != nil {
-		return fmt.Errorf("state db err: %v", err)
-	}
-	defer chainDb.Close()
+	if db, ok := db.(*ethdb.LDBDatabase); ok {
+		blockPrefix := []byte("block-hash-")
+		for it := db.NewIterator(); it.Next(); {
+			// Skip anything other than a combined block
+			if !bytes.HasPrefix(it.Key(), blockPrefix) {
+				continue
+			}
+			// Skip the head block (merge last to signal upgrade completion)
+			if bytes.HasSuffix(it.Key(), head.Bytes()) {
+				continue
+			}
+			// Load the block, split and serialize (order!)
+			block := core.GetBlockByHashOld(db, common.BytesToHash(bytes.TrimPrefix(it.Key(), blockPrefix)))
 
-	if chain, ok := chainDb.(*ethdb.LDBDatabase); ok {
-		glog.Infoln("Merging blockchain database...")
-		it := chain.NewIterator()
-		for it.Next() {
-			database.Put(it.Key(), it.Value())
+			if err := core.WriteTd(db, block.Hash(), block.DeprecatedTd()); err != nil {
+				return err
+			}
+			if err := core.WriteBody(db, block.Hash(), &types.Body{block.Transactions(), block.Uncles()}); err != nil {
+				return err
+			}
+			if err := core.WriteHeader(db, block.Header()); err != nil {
+				return err
+			}
+			if err := db.Delete(it.Key()); err != nil {
+				return err
+			}
 		}
-		it.Release()
-	}
-
-	// Migrate state
-	stateDb, err := newdb(filepath.Join(datadir, "state"))
-	if err != nil {
-		return fmt.Errorf("state db err: %v", err)
-	}
-	defer stateDb.Close()
+		// Lastly, upgrade the head block, disabling the upgrade mechanism
+		current := core.GetBlockByHashOld(db, head)
 
-	if state, ok := stateDb.(*ethdb.LDBDatabase); ok {
-		glog.Infoln("Merging state database...")
-		it := state.NewIterator()
-		for it.Next() {
-			database.Put(it.Key(), it.Value())
+		if err := core.WriteTd(db, current.Hash(), current.DeprecatedTd()); err != nil {
+			return err
 		}
-		it.Release()
-	}
-
-	// Migrate transaction / receipts
-	extraDb, err := newdb(filepath.Join(datadir, "extra"))
-	if err != nil {
-		return fmt.Errorf("state db err: %v", err)
-	}
-	defer extraDb.Close()
-
-	if extra, ok := extraDb.(*ethdb.LDBDatabase); ok {
-		glog.Infoln("Merging transaction database...")
-
-		it := extra.NewIterator()
-		for it.Next() {
-			database.Put(it.Key(), it.Value())
+		if err := core.WriteBody(db, current.Hash(), &types.Body{current.Transactions(), current.Uncles()}); err != nil {
+			return err
+		}
+		if err := core.WriteHeader(db, current.Header()); err != nil {
+			return err
 		}
-		it.Release()
 	}
-
 	return nil
 }
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 73f95bf64..d28985b3e 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -87,6 +87,9 @@ type blockRetrievalFn func(common.Hash) *types.Block
 // headRetrievalFn is a callback type for retrieving the head block from the local chain.
 type headRetrievalFn func() *types.Block
 
+// tdRetrievalFn is a callback type for retrieving the total difficulty of a local block.
+type tdRetrievalFn func(common.Hash) *big.Int
+
 // chainInsertFn is a callback type to insert a batch of blocks into the local chain.
 type chainInsertFn func(types.Blocks) (int, error)
 
@@ -136,6 +139,7 @@ type Downloader struct {
 	hasBlock    hashCheckFn      // Checks if a block is present in the chain
 	getBlock    blockRetrievalFn // Retrieves a block from the chain
 	headBlock   headRetrievalFn  // Retrieves the head block from the chain
+	getTd       tdRetrievalFn    // Retrieves the TD of a block from the chain
 	insertChain chainInsertFn    // Injects a batch of blocks into the chain
 	dropPeer    peerDropFn       // Drops a peer for misbehaving
 
@@ -168,7 +172,7 @@ type Block struct {
 }
 
 // New creates a new downloader to fetch hashes and blocks from remote peers.
-func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, headBlock headRetrievalFn, insertChain chainInsertFn, dropPeer peerDropFn) *Downloader {
+func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, headBlock headRetrievalFn, getTd tdRetrievalFn, insertChain chainInsertFn, dropPeer peerDropFn) *Downloader {
 	return &Downloader{
 		mux:         mux,
 		queue:       newQueue(),
@@ -176,6 +180,7 @@ func New(mux *event.TypeMux, hasBlock hashCheckFn, getBlock blockRetrievalFn, he
 		hasBlock:    hasBlock,
 		getBlock:    getBlock,
 		headBlock:   headBlock,
+		getTd:       getTd,
 		insertChain: insertChain,
 		dropPeer:    dropPeer,
 		newPeerCh:   make(chan *peer, 1),
@@ -582,7 +587,7 @@ func (d *Downloader) fetchHashes61(p *peer, td *big.Int, from uint64) error {
 				// L: Sync begins, and finds common ancestor at 11
 				// L: Request new hashes up from 11 (R's TD was higher, it must have something)
 				// R: Nothing to give
-				if !gotHashes && td.Cmp(d.headBlock().Td) > 0 {
+				if !gotHashes && td.Cmp(d.getTd(d.headBlock().Hash())) > 0 {
 					return errStallingPeer
 				}
 				return nil
@@ -958,7 +963,7 @@ func (d *Downloader) fetchHeaders(p *peer, td *big.Int, from uint64) error {
 				// L: Sync begins, and finds common ancestor at 11
 				// L: Request new headers up from 11 (R's TD was higher, it must have something)
 				// R: Nothing to give
-				if !gotHeaders && td.Cmp(d.headBlock().Td) > 0 {
+				if !gotHeaders && td.Cmp(d.getTd(d.headBlock().Hash())) > 0 {
 					return errStallingPeer
 				}
 				return nil
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 8d009b671..dbcf93607 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -93,21 +93,25 @@ func makeChainFork(n, f int, parent *types.Block) (h1, h2 []common.Hash, b1, b2
 type downloadTester struct {
 	downloader *Downloader
 
-	ownHashes  []common.Hash                           // Hash chain belonging to the tester
-	ownBlocks  map[common.Hash]*types.Block            // Blocks belonging to the tester
-	peerHashes map[string][]common.Hash                // Hash chain belonging to different test peers
-	peerBlocks map[string]map[common.Hash]*types.Block // Blocks belonging to different test peers
+	ownHashes    []common.Hash                           // Hash chain belonging to the tester
+	ownBlocks    map[common.Hash]*types.Block            // Blocks belonging to the tester
+	ownChainTd   map[common.Hash]*big.Int                // Total difficulties of the blocks in the local chain
+	peerHashes   map[string][]common.Hash                // Hash chain belonging to different test peers
+	peerBlocks   map[string]map[common.Hash]*types.Block // Blocks belonging to different test peers
+	peerChainTds map[string]map[common.Hash]*big.Int     // Total difficulties of the blocks in the peer chains
 }
 
 // newTester creates a new downloader test mocker.
 func newTester() *downloadTester {
 	tester := &downloadTester{
-		ownHashes:  []common.Hash{genesis.Hash()},
-		ownBlocks:  map[common.Hash]*types.Block{genesis.Hash(): genesis},
-		peerHashes: make(map[string][]common.Hash),
-		peerBlocks: make(map[string]map[common.Hash]*types.Block),
+		ownHashes:    []common.Hash{genesis.Hash()},
+		ownBlocks:    map[common.Hash]*types.Block{genesis.Hash(): genesis},
+		ownChainTd:   map[common.Hash]*big.Int{genesis.Hash(): genesis.Difficulty()},
+		peerHashes:   make(map[string][]common.Hash),
+		peerBlocks:   make(map[string]map[common.Hash]*types.Block),
+		peerChainTds: make(map[string]map[common.Hash]*big.Int),
 	}
-	tester.downloader = New(new(event.TypeMux), tester.hasBlock, tester.getBlock, tester.headBlock, tester.insertChain, tester.dropPeer)
+	tester.downloader = New(new(event.TypeMux), tester.hasBlock, tester.getBlock, tester.headBlock, tester.getTd, tester.insertChain, tester.dropPeer)
 
 	return tester
 }
@@ -119,8 +123,8 @@ func (dl *downloadTester) sync(id string, td *big.Int) error {
 	// If no particular TD was requested, load from the peer's blockchain
 	if td == nil {
 		td = big.NewInt(1)
-		if block, ok := dl.peerBlocks[id][hash]; ok {
-			td = block.Td
+		if diff, ok := dl.peerChainTds[id][hash]; ok {
+			td = diff
 		}
 	}
 	err := dl.downloader.synchronise(id, hash, td)
@@ -152,6 +156,11 @@ func (dl *downloadTester) headBlock() *types.Block {
 	return dl.getBlock(dl.ownHashes[len(dl.ownHashes)-1])
 }
 
+// getTd retrieves the block's total difficulty from the canonical chain.
+func (dl *downloadTester) getTd(hash common.Hash) *big.Int {
+	return dl.ownChainTd[hash]
+}
+
 // insertChain injects a new batch of blocks into the simulated chain.
 func (dl *downloadTester) insertChain(blocks types.Blocks) (int, error) {
 	for i, block := range blocks {
@@ -160,6 +169,7 @@ func (dl *downloadTester) insertChain(blocks types.Blocks) (int, error) {
 		}
 		dl.ownHashes = append(dl.ownHashes, block.Hash())
 		dl.ownBlocks[block.Hash()] = block
+		dl.ownChainTd[block.Hash()] = dl.ownChainTd[block.ParentHash()]
 	}
 	return len(blocks), nil
 }
@@ -180,9 +190,16 @@ func (dl *downloadTester) newSlowPeer(id string, version int, hashes []common.Ha
 		// Assign the owned hashes and blocks to the peer (deep copy)
 		dl.peerHashes[id] = make([]common.Hash, len(hashes))
 		copy(dl.peerHashes[id], hashes)
+
 		dl.peerBlocks[id] = make(map[common.Hash]*types.Block)
-		for hash, block := range blocks {
-			dl.peerBlocks[id][hash] = block
+		dl.peerChainTds[id] = make(map[common.Hash]*big.Int)
+		for _, hash := range hashes {
+			if block, ok := blocks[hash]; ok {
+				dl.peerBlocks[id][hash] = block
+				if parent, ok := dl.peerBlocks[id][block.ParentHash()]; ok {
+					dl.peerChainTds[id][hash] = new(big.Int).Add(block.Difficulty(), dl.peerChainTds[id][parent.Hash()])
+				}
+			}
 		}
 	}
 	return err
@@ -192,6 +209,7 @@ func (dl *downloadTester) newSlowPeer(id string, version int, hashes []common.Ha
 func (dl *downloadTester) dropPeer(id string) {
 	delete(dl.peerHashes, id)
 	delete(dl.peerBlocks, id)
+	delete(dl.peerChainTds, id)
 
 	dl.downloader.UnregisterPeer(id)
 }
diff --git a/eth/handler.go b/eth/handler.go
index f22afecb7..4aef69043 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -36,8 +36,10 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
-// This is the target maximum size of returned blocks, headers or node data.
-const softResponseLimit = 2 * 1024 * 1024
+const (
+	softResponseLimit = 2 * 1024 * 1024 // Target maximum size of returned blocks, headers or node data.
+	estHeaderRlpSize  = 500             // Approximate size of an RLP encoded block header
+)
 
 func errResp(code errCode, format string, v ...interface{}) error {
 	return fmt.Errorf("%v - %v", code, fmt.Sprintf(format, v...))
@@ -113,7 +115,7 @@ func NewProtocolManager(networkId int, mux *event.TypeMux, txpool txPool, pow po
 		}
 	}
 	// Construct the different synchronisation mechanisms
-	manager.downloader = downloader.New(manager.eventMux, manager.chainman.HasBlock, manager.chainman.GetBlock, manager.chainman.CurrentBlock, manager.chainman.InsertChain, manager.removePeer)
+	manager.downloader = downloader.New(manager.eventMux, manager.chainman.HasBlock, manager.chainman.GetBlock, manager.chainman.CurrentBlock, manager.chainman.GetTd, manager.chainman.InsertChain, manager.removePeer)
 
 	validator := func(block *types.Block, parent *types.Block) error {
 		return core.ValidateHeader(pow, block.Header(), parent, true, false)
@@ -345,33 +347,33 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 		if err := msg.Decode(&query); err != nil {
 			return errResp(ErrDecode, "%v: %v", msg, err)
 		}
-		// Gather blocks until the fetch or network limits is reached
+		// Gather headers until the fetch or network limits is reached
 		var (
 			bytes   common.StorageSize
 			headers []*types.Header
 			unknown bool
 		)
 		for !unknown && len(headers) < int(query.Amount) && bytes < softResponseLimit && len(headers) < downloader.MaxHeaderFetch {
-			// Retrieve the next block satisfying the query
-			var origin *types.Block
+			// Retrieve the next header satisfying the query
+			var origin *types.Header
 			if query.Origin.Hash != (common.Hash{}) {
-				origin = pm.chainman.GetBlock(query.Origin.Hash)
+				origin = pm.chainman.GetHeader(query.Origin.Hash)
 			} else {
-				origin = pm.chainman.GetBlockByNumber(query.Origin.Number)
+				origin = pm.chainman.GetHeaderByNumber(query.Origin.Number)
 			}
 			if origin == nil {
 				break
 			}
-			headers = append(headers, origin.Header())
-			bytes += origin.Size()
+			headers = append(headers, origin)
+			bytes += estHeaderRlpSize
 
-			// Advance to the next block of the query
+			// Advance to the next header of the query
 			switch {
 			case query.Origin.Hash != (common.Hash{}) && query.Reverse:
 				// Hash based traversal towards the genesis block
 				for i := 0; i < int(query.Skip)+1; i++ {
-					if block := pm.chainman.GetBlock(query.Origin.Hash); block != nil {
-						query.Origin.Hash = block.ParentHash()
+					if header := pm.chainman.GetHeader(query.Origin.Hash); header != nil {
+						query.Origin.Hash = header.ParentHash
 					} else {
 						unknown = true
 						break
@@ -379,9 +381,9 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 				}
 			case query.Origin.Hash != (common.Hash{}) && !query.Reverse:
 				// Hash based traversal towards the leaf block
-				if block := pm.chainman.GetBlockByNumber(origin.NumberU64() + query.Skip + 1); block != nil {
-					if pm.chainman.GetBlockHashesFromHash(block.Hash(), query.Skip+1)[query.Skip] == query.Origin.Hash {
-						query.Origin.Hash = block.Hash()
+				if header := pm.chainman.GetHeaderByNumber(origin.Number.Uint64() + query.Skip + 1); header != nil {
+					if pm.chainman.GetBlockHashesFromHash(header.Hash(), query.Skip+1)[query.Skip] == query.Origin.Hash {
+						query.Origin.Hash = header.Hash()
 					} else {
 						unknown = true
 					}
@@ -452,23 +454,23 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 		// Gather blocks until the fetch or network limits is reached
 		var (
 			hash   common.Hash
-			bytes  common.StorageSize
-			bodies []*blockBody
+			bytes  int
+			bodies []rlp.RawValue
 		)
 		for bytes < softResponseLimit && len(bodies) < downloader.MaxBlockFetch {
-			//Retrieve the hash of the next block
+			// Retrieve the hash of the next block
 			if err := msgStream.Decode(&hash); err == rlp.EOL {
 				break
 			} else if err != nil {
 				return errResp(ErrDecode, "msg %v: %v", msg, err)
 			}
-			// Retrieve the requested block, stopping if enough was found
-			if block := pm.chainman.GetBlock(hash); block != nil {
-				bodies = append(bodies, &blockBody{Transactions: block.Transactions(), Uncles: block.Uncles()})
-				bytes += block.Size()
+			// Retrieve the requested block body, stopping if enough was found
+			if data := pm.chainman.GetBodyRLP(hash); len(data) != 0 {
+				bodies = append(bodies, data)
+				bytes += len(data)
 			}
 		}
-		return p.SendBlockBodies(bodies)
+		return p.SendBlockBodiesRLP(bodies)
 
 	case p.version >= eth63 && msg.Code == GetNodeDataMsg:
 		// Decode the retrieval message
@@ -643,7 +645,7 @@ func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) {
 		// Calculate the TD of the block (it's not imported yet, so block.Td is not valid)
 		var td *big.Int
 		if parent := pm.chainman.GetBlock(block.ParentHash()); parent != nil {
-			td = new(big.Int).Add(parent.Td, block.Difficulty())
+			td = new(big.Int).Add(block.Difficulty(), pm.chainman.GetTd(block.ParentHash()))
 		} else {
 			glog.V(logger.Error).Infof("propagating dangling block #%d [%x]", block.NumberU64(), hash[:4])
 			return
diff --git a/eth/peer.go b/eth/peer.go
index 8d7c48885..603b49b88 100644
--- a/eth/peer.go
+++ b/eth/peer.go
@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/rlp"
 	"gopkg.in/fatih/set.v0"
 )
 
@@ -184,6 +185,12 @@ func (p *peer) SendBlockBodies(bodies []*blockBody) error {
 	return p2p.Send(p.rw, BlockBodiesMsg, blockBodiesData(bodies))
 }
 
+// SendBlockBodiesRLP sends a batch of block contents to the remote peer from
+// an already RLP encoded format.
+func (p *peer) SendBlockBodiesRLP(bodies []rlp.RawValue) error {
+	return p2p.Send(p.rw, BlockBodiesMsg, bodies)
+}
+
 // SendNodeData sends a batch of arbitrary internal data, corresponding to the
 // hashes requested.
 func (p *peer) SendNodeData(data [][]byte) error {
diff --git a/miner/worker.go b/miner/worker.go
index 16a16931d..2f43b110f 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -283,7 +283,7 @@ func (self *worker) wait() {
 					continue
 				}
 
-				stat, err := self.chain.WriteBlock(block, false)
+				stat, err := self.chain.WriteBlock(block)
 				if err != nil {
 					glog.V(logger.Error).Infoln("error writing block to chain", err)
 					continue
@@ -533,14 +533,12 @@ func (self *worker) commitNewWork() {
 
 	// create the new block whose nonce will be mined.
 	work.Block = types.NewBlock(header, work.txs, uncles, work.receipts)
-	work.Block.Td = new(big.Int).Set(core.CalcTD(work.Block, self.chain.GetBlock(work.Block.ParentHash())))
 
 	// We only care about logging if we're actually mining.
 	if atomic.LoadInt32(&self.mining) == 1 {
 		glog.V(logger.Info).Infof("commit new work on block %v with %d txs & %d uncles. Took %v\n", work.Block.Number(), work.tcount, len(uncles), time.Since(tstart))
 		self.logLocalMinedBlocks(work, previous)
 	}
-
 	self.push(work)
 }
 
diff --git a/rpc/api/eth.go b/rpc/api/eth.go
index ba87e86c6..a93e41157 100644
--- a/rpc/api/eth.go
+++ b/rpc/api/eth.go
@@ -204,7 +204,8 @@ func (self *ethApi) GetBlockTransactionCountByHash(req *shared.Request) (interfa
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := NewBlockRes(self.xeth.EthBlockByHash(args.Hash), false)
+	raw := self.xeth.EthBlockByHash(args.Hash)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), false)
 	if block == nil {
 		return nil, nil
 	} else {
@@ -218,7 +219,8 @@ func (self *ethApi) GetBlockTransactionCountByNumber(req *shared.Request) (inter
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := NewBlockRes(self.xeth.EthBlockByNumber(args.BlockNumber), false)
+	raw := self.xeth.EthBlockByNumber(args.BlockNumber)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), false)
 	if block == nil {
 		return nil, nil
 	} else {
@@ -232,12 +234,12 @@ func (self *ethApi) GetUncleCountByBlockHash(req *shared.Request) (interface{},
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := self.xeth.EthBlockByHash(args.Hash)
-	br := NewBlockRes(block, false)
-	if br == nil {
+	raw := self.xeth.EthBlockByHash(args.Hash)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), false)
+	if block == nil {
 		return nil, nil
 	}
-	return newHexNum(big.NewInt(int64(len(br.Uncles))).Bytes()), nil
+	return newHexNum(big.NewInt(int64(len(block.Uncles))).Bytes()), nil
 }
 
 func (self *ethApi) GetUncleCountByBlockNumber(req *shared.Request) (interface{}, error) {
@@ -246,12 +248,12 @@ func (self *ethApi) GetUncleCountByBlockNumber(req *shared.Request) (interface{}
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := self.xeth.EthBlockByNumber(args.BlockNumber)
-	br := NewBlockRes(block, false)
-	if br == nil {
+	raw := self.xeth.EthBlockByNumber(args.BlockNumber)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), false)
+	if block == nil {
 		return nil, nil
 	}
-	return newHexNum(big.NewInt(int64(len(br.Uncles))).Bytes()), nil
+	return newHexNum(big.NewInt(int64(len(block.Uncles))).Bytes()), nil
 }
 
 func (self *ethApi) GetData(req *shared.Request) (interface{}, error) {
@@ -362,7 +364,7 @@ func (self *ethApi) GetBlockByHash(req *shared.Request) (interface{}, error) {
 	}
 
 	block := self.xeth.EthBlockByHash(args.BlockHash)
-	return NewBlockRes(block, args.IncludeTxs), nil
+	return NewBlockRes(block, self.xeth.Td(block.Hash()), args.IncludeTxs), nil
 }
 
 func (self *ethApi) GetBlockByNumber(req *shared.Request) (interface{}, error) {
@@ -372,8 +374,7 @@ func (self *ethApi) GetBlockByNumber(req *shared.Request) (interface{}, error) {
 	}
 
 	block := self.xeth.EthBlockByNumber(args.BlockNumber)
-	br := NewBlockRes(block, args.IncludeTxs)
-	return br, nil
+	return NewBlockRes(block, self.xeth.Td(block.Hash()), args.IncludeTxs), nil
 }
 
 func (self *ethApi) GetTransactionByHash(req *shared.Request) (interface{}, error) {
@@ -402,16 +403,15 @@ func (self *ethApi) GetTransactionByBlockHashAndIndex(req *shared.Request) (inte
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := self.xeth.EthBlockByHash(args.Hash)
-	br := NewBlockRes(block, true)
-	if br == nil {
+	raw := self.xeth.EthBlockByHash(args.Hash)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), true)
+	if block == nil {
 		return nil, nil
 	}
-
-	if args.Index >= int64(len(br.Transactions)) || args.Index < 0 {
+	if args.Index >= int64(len(block.Transactions)) || args.Index < 0 {
 		return nil, nil
 	} else {
-		return br.Transactions[args.Index], nil
+		return block.Transactions[args.Index], nil
 	}
 }
 
@@ -421,17 +421,16 @@ func (self *ethApi) GetTransactionByBlockNumberAndIndex(req *shared.Request) (in
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := self.xeth.EthBlockByNumber(args.BlockNumber)
-	v := NewBlockRes(block, true)
-	if v == nil {
+	raw := self.xeth.EthBlockByNumber(args.BlockNumber)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), true)
+	if block == nil {
 		return nil, nil
 	}
-
-	if args.Index >= int64(len(v.Transactions)) || args.Index < 0 {
+	if args.Index >= int64(len(block.Transactions)) || args.Index < 0 {
 		// return NewValidationError("Index", "does not exist")
 		return nil, nil
 	}
-	return v.Transactions[args.Index], nil
+	return block.Transactions[args.Index], nil
 }
 
 func (self *ethApi) GetUncleByBlockHashAndIndex(req *shared.Request) (interface{}, error) {
@@ -440,17 +439,16 @@ func (self *ethApi) GetUncleByBlockHashAndIndex(req *shared.Request) (interface{
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	br := NewBlockRes(self.xeth.EthBlockByHash(args.Hash), false)
-	if br == nil {
+	raw := self.xeth.EthBlockByHash(args.Hash)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), false)
+	if block == nil {
 		return nil, nil
 	}
-
-	if args.Index >= int64(len(br.Uncles)) || args.Index < 0 {
+	if args.Index >= int64(len(block.Uncles)) || args.Index < 0 {
 		// return NewValidationError("Index", "does not exist")
 		return nil, nil
 	}
-
-	return br.Uncles[args.Index], nil
+	return block.Uncles[args.Index], nil
 }
 
 func (self *ethApi) GetUncleByBlockNumberAndIndex(req *shared.Request) (interface{}, error) {
@@ -459,17 +457,15 @@ func (self *ethApi) GetUncleByBlockNumberAndIndex(req *shared.Request) (interfac
 		return nil, shared.NewDecodeParamError(err.Error())
 	}
 
-	block := self.xeth.EthBlockByNumber(args.BlockNumber)
-	v := NewBlockRes(block, true)
-
-	if v == nil {
+	raw := self.xeth.EthBlockByNumber(args.BlockNumber)
+	block := NewBlockRes(raw, self.xeth.Td(raw.Hash()), true)
+	if block == nil {
 		return nil, nil
 	}
-
-	if args.Index >= int64(len(v.Uncles)) || args.Index < 0 {
+	if args.Index >= int64(len(block.Uncles)) || args.Index < 0 {
 		return nil, nil
 	} else {
-		return v.Uncles[args.Index], nil
+		return block.Uncles[args.Index], nil
 	}
 }
 
diff --git a/rpc/api/parsing.go b/rpc/api/parsing.go
index 5858bc136..cdfaa0ed1 100644
--- a/rpc/api/parsing.go
+++ b/rpc/api/parsing.go
@@ -281,7 +281,7 @@ func (b *BlockRes) MarshalJSON() ([]byte, error) {
 	}
 }
 
-func NewBlockRes(block *types.Block, fullTx bool) *BlockRes {
+func NewBlockRes(block *types.Block, td *big.Int, fullTx bool) *BlockRes {
 	if block == nil {
 		return nil
 	}
@@ -299,7 +299,7 @@ func NewBlockRes(block *types.Block, fullTx bool) *BlockRes {
 	res.ReceiptRoot = newHexData(block.ReceiptHash())
 	res.Miner = newHexData(block.Coinbase())
 	res.Difficulty = newHexNum(block.Difficulty())
-	res.TotalDifficulty = newHexNum(block.Td)
+	res.TotalDifficulty = newHexNum(td)
 	res.Size = newHexNum(block.Size().Int64())
 	res.ExtraData = newHexData(block.Extra())
 	res.GasLimit = newHexNum(block.GasLimit())
diff --git a/tests/block_test_util.go b/tests/block_test_util.go
index 2090afce7..30488951d 100644
--- a/tests/block_test_util.go
+++ b/tests/block_test_util.go
@@ -440,9 +440,8 @@ func convertBlockTest(in *btJSON) (out *BlockTest, err error) {
 func mustConvertGenesis(testGenesis btHeader) *types.Block {
 	hdr := mustConvertHeader(testGenesis)
 	hdr.Number = big.NewInt(0)
-	b := types.NewBlockWithHeader(hdr)
-	b.Td = new(big.Int)
-	return b
+
+	return types.NewBlockWithHeader(hdr)
 }
 
 func mustConvertHeader(in btHeader) *types.Header {
diff --git a/xeth/xeth.go b/xeth/xeth.go
index 8bd45998f..00b70da6c 100644
--- a/xeth/xeth.go
+++ b/xeth/xeth.go
@@ -355,6 +355,10 @@ func (self *XEth) EthBlockByNumber(num int64) *types.Block {
 	return self.getBlockByHeight(num)
 }
 
+func (self *XEth) Td(hash common.Hash) *big.Int {
+	return self.backend.ChainManager().GetTd(hash)
+}
+
 func (self *XEth) CurrentBlock() *types.Block {
 	return self.backend.ChainManager().CurrentBlock()
 }