core, eth, miner: only retain 1 tx/nonce, remove bad ones

6 files changed, 282 insertions, 207 deletions

diff --git a/core/tx_pool.go b/core/tx_pool.go
index 596356377..ec3d5c16b 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -51,6 +51,11 @@ const (
 
 type stateFn func() (*state.StateDB, error)
 
+// TxList is a "list" of transactions belonging to an account, sorted by account
+// nonce. To allow gaps and avoid constant copying, the list is represented as a
+// hash map.
+type TxList map[uint64]*types.Transaction
+
 // TxPool contains all currently known transactions. Transactions
 // enter the pool when they are received from the network or submitted
 // locally. They exit the pool when they are included in the blockchain.
@@ -68,8 +73,10 @@ type TxPool struct {
 	events       event.Subscription
 	localTx      *txSet
 	mu           sync.RWMutex
-	pending      map[common.Hash]*types.Transaction // processable transactions
-	queue        map[common.Address]map[common.Hash]*types.Transaction
+
+	pending map[common.Address]TxList          // All currently processable transactions
+	queue   map[common.Address]TxList          // Queued but non-processable transactions
+	all     map[common.Hash]*types.Transaction // All transactions to allow lookups
 
 	wg sync.WaitGroup // for shutdown sync
 
@@ -79,8 +86,9 @@ type TxPool struct {
 func NewTxPool(config *ChainConfig, eventMux *event.TypeMux, currentStateFn stateFn, gasLimitFn func() *big.Int) *TxPool {
 	pool := &TxPool{
 		config:       config,
-		pending:      make(map[common.Hash]*types.Transaction),
-		queue:        make(map[common.Address]map[common.Hash]*types.Transaction),
+		pending:      make(map[common.Address]TxList),
+		queue:        make(map[common.Address]TxList),
+		all:          make(map[common.Hash]*types.Transaction),
 		eventMux:     eventMux,
 		currentState: currentStateFn,
 		gasLimit:     gasLimitFn,
@@ -143,12 +151,12 @@ func (pool *TxPool) resetState() {
 
 	// Loop over the pending transactions and base the nonce of the new
 	// pending transaction set.
-	for _, tx := range pool.pending {
-		if addr, err := tx.From(); err == nil {
-			// Set the nonce. Transaction nonce can never be lower
-			// than the state nonce; validatePool took care of that.
-			if pool.pendingState.GetNonce(addr) <= tx.Nonce() {
-				pool.pendingState.SetNonce(addr, tx.Nonce()+1)
+	for addr, txs := range pool.pending {
+		// Set the nonce. Transaction nonce can never be lower
+		// than the state nonce; validatePool took care of that.
+		for nonce, _ := range txs {
+			if pool.pendingState.GetNonce(addr) <= nonce {
+				pool.pendingState.SetNonce(addr, nonce+1)
 			}
 		}
 	}
@@ -174,7 +182,9 @@ func (pool *TxPool) Stats() (pending int, queued int) {
 	pool.mu.RLock()
 	defer pool.mu.RUnlock()
 
-	pending = len(pool.pending)
+	for _, txs := range pool.pending {
+		pending += len(txs)
+	}
 	for _, txs := range pool.queue {
 		queued += len(txs)
 	}
@@ -183,30 +193,27 @@ func (pool *TxPool) Stats() (pending int, queued int) {
 
 // Content retrieves the data content of the transaction pool, returning all the
 // pending as well as queued transactions, grouped by account and nonce.
-func (pool *TxPool) Content() (map[common.Address]map[uint64][]*types.Transaction, map[common.Address]map[uint64][]*types.Transaction) {
+func (pool *TxPool) Content() (map[common.Address]TxList, map[common.Address]TxList) {
 	pool.mu.RLock()
 	defer pool.mu.RUnlock()
 
 	// Retrieve all the pending transactions and sort by account and by nonce
-	pending := make(map[common.Address]map[uint64][]*types.Transaction)
-	for _, tx := range pool.pending {
-		account, _ := tx.From()
-
-		owned, ok := pending[account]
-		if !ok {
-			owned = make(map[uint64][]*types.Transaction)
-			pending[account] = owned
+	pending := make(map[common.Address]TxList)
+	for addr, txs := range pool.pending {
+		copy := make(TxList)
+		for nonce, tx := range txs {
+			copy[nonce] = tx
 		}
-		owned[tx.Nonce()] = append(owned[tx.Nonce()], tx)
+		pending[addr] = copy
 	}
 	// Retrieve all the queued transactions and sort by account and by nonce
-	queued := make(map[common.Address]map[uint64][]*types.Transaction)
-	for account, txs := range pool.queue {
-		owned := make(map[uint64][]*types.Transaction)
-		for _, tx := range txs {
-			owned[tx.Nonce()] = append(owned[tx.Nonce()], tx)
+	queued := make(map[common.Address]TxList)
+	for addr, txs := range pool.queue {
+		copy := make(TxList)
+		for nonce, tx := range txs {
+			copy[nonce] = tx
 		}
-		queued[account] = owned
+		queued[addr] = copy
 	}
 	return pending, queued
 }
@@ -280,7 +287,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction) error {
 func (self *TxPool) add(tx *types.Transaction) error {
 	hash := tx.Hash()
 
-	if self.pending[hash] != nil {
+	if self.all[hash] != nil {
 		return fmt.Errorf("Known transaction (%x)", hash[:4])
 	}
 	err := self.validateTx(tx)
@@ -306,33 +313,63 @@ func (self *TxPool) add(tx *types.Transaction) error {
 	return nil
 }
 
-// queueTx will queue an unknown transaction
+// queueTx will queue an unknown transaction.
 func (self *TxPool) queueTx(hash common.Hash, tx *types.Transaction) {
-	from, _ := tx.From() // already validated
-	if self.queue[from] == nil {
-		self.queue[from] = make(map[common.Hash]*types.Transaction)
+	addr, _ := tx.From() // already validated
+	if self.queue[addr] == nil {
+		self.queue[addr] = make(TxList)
 	}
-	self.queue[from][hash] = tx
+	// If the nonce is already used, discard the lower priced transaction
+	nonce := tx.Nonce()
+
+	if old, ok := self.queue[addr][nonce]; ok {
+		if old.GasPrice().Cmp(tx.GasPrice()) >= 0 {
+			return // Old was better, discard this
+		}
+		delete(self.all, old.Hash()) // New is better, drop and overwrite old one
+	}
+	self.queue[addr][nonce] = tx
+	self.all[hash] = tx
 }
 
-// addTx will add a transaction to the pending (processable queue) list of transactions
-func (pool *TxPool) addTx(hash common.Hash, addr common.Address, tx *types.Transaction) {
-	// init delayed since tx pool could have been started before any state sync
+// addTx will moves a transaction from the non-executable queue to the pending
+// (processable) list of transactions.
+func (pool *TxPool) addTx(addr common.Address, tx *types.Transaction) {
+	// Init delayed since tx pool could have been started before any state sync
 	if pool.pendingState == nil {
 		pool.resetState()
 	}
+	// If the nonce is already used, discard the lower priced transaction
+	hash, nonce := tx.Hash(), tx.Nonce()
 
-	if _, ok := pool.pending[hash]; !ok {
-		pool.pending[hash] = tx
+	if old, ok := pool.pending[addr][nonce]; ok {
+		oldHash := old.Hash()
 
-		// Increment the nonce on the pending state. This can only happen if
-		// the nonce is +1 to the previous one.
-		pool.pendingState.SetNonce(addr, tx.Nonce()+1)
-		// Notify the subscribers. This event is posted in a goroutine
-		// because it's possible that somewhere during the post "Remove transaction"
-		// gets called which will then wait for the global tx pool lock and deadlock.
-		go pool.eventMux.Post(TxPreEvent{tx})
+		switch {
+		case oldHash == hash: // Nothing changed, noop
+			return
+		case old.GasPrice().Cmp(tx.GasPrice()) >= 0: // Old was better, discard this
+			delete(pool.all, hash)
+			return
+		default: // New is better, discard old
+			delete(pool.all, oldHash)
+		}
+	}
+	// The transaction is being kept, insert it into the tx pool
+	if _, ok := pool.pending[addr]; !ok {
+		pool.pending[addr] = make(TxList)
 	}
+	pool.pending[addr][nonce] = tx
+	pool.all[hash] = tx
+
+	// Increment the nonce on the pending state. This can only happen if
+	// the nonce is +1 to the previous one.
+	pool.pendingState.SetNonce(addr, nonce+1)
+
+	// Notify the subscribers. This event is posted in a goroutine
+	// because it's possible that somewhere during the post "Remove transaction"
+	// gets called which will then wait for the global tx pool lock and deadlock.
+	go pool.eventMux.Post(TxPreEvent{tx})
 }
 
 // Add queues a single transaction in the pool if it is valid.
@@ -371,58 +408,39 @@ func (tp *TxPool) GetTransaction(hash common.Hash) *types.Transaction {
 	tp.mu.RLock()
 	defer tp.mu.RUnlock()
 
-	// check the txs first
-	if tx, ok := tp.pending[hash]; ok {
-		return tx
-	}
-	// check queue
-	for _, txs := range tp.queue {
-		if tx, ok := txs[hash]; ok {
-			return tx
-		}
-	}
-	return nil
+	return tp.all[hash]
 }
 
 // GetTransactions returns all currently processable transactions.
 // The returned slice may be modified by the caller.
-func (self *TxPool) GetTransactions() (txs types.Transactions) {
+func (self *TxPool) GetTransactions() types.Transactions {
 	self.mu.Lock()
 	defer self.mu.Unlock()
 
 	// check queue first
 	self.checkQueue()
+
 	// invalidate any txs
 	self.validatePool()
 
-	txs = make(types.Transactions, len(self.pending))
-	i := 0
-	for _, tx := range self.pending {
-		txs[i] = tx
-		i++
+	count := 0
+	for _, txs := range self.pending {
+		count += len(txs)
 	}
-	return txs
-}
-
-// GetQueuedTransactions returns all non-processable transactions.
-func (self *TxPool) GetQueuedTransactions() types.Transactions {
-	self.mu.RLock()
-	defer self.mu.RUnlock()
-
-	var ret types.Transactions
-	for _, txs := range self.queue {
+	pending := make(types.Transactions, 0, count)
+	for _, txs := range self.pending {
 		for _, tx := range txs {
-			ret = append(ret, tx)
+			pending = append(pending, tx)
 		}
 	}
-	sort.Sort(types.TxByNonce(ret))
-	return ret
+	return pending
 }
 
 // RemoveTransactions removes all given transactions from the pool.
 func (self *TxPool) RemoveTransactions(txs types.Transactions) {
 	self.mu.Lock()
 	defer self.mu.Unlock()
+
 	for _, tx := range txs {
 		self.removeTx(tx.Hash())
 	}
@@ -432,29 +450,35 @@ func (self *TxPool) RemoveTransactions(txs types.Transactions) {
 func (pool *TxPool) RemoveTx(hash common.Hash) {
 	pool.mu.Lock()
 	defer pool.mu.Unlock()
+
 	pool.removeTx(hash)
 }
 
 func (pool *TxPool) removeTx(hash common.Hash) {
-	// delete from pending pool
-	delete(pool.pending, hash)
-	// delete from queue
-	for address, txs := range pool.queue {
-		if _, ok := txs[hash]; ok {
-			if len(txs) == 1 {
-				// if only one tx, remove entire address entry.
-				delete(pool.queue, address)
-			} else {
-				delete(txs, hash)
-			}
-			break
-		}
+	// Fetch the transaction we wish to delete
+	tx, ok := pool.all[hash]
+	if !ok {
+		return
+	}
+	addr, _ := tx.From()
+
+	// Remove it from all internal lists
+	delete(pool.all, hash)
+
+	delete(pool.pending[addr], tx.Nonce())
+	if len(pool.pending[addr]) == 0 {
+		delete(pool.pending, addr)
+	}
+	delete(pool.queue[addr], tx.Nonce())
+	if len(pool.queue[addr]) == 0 {
+		delete(pool.queue, addr)
 	}
 }
 
-// checkQueue moves transactions that have become processable to main pool.
+// checkQueue moves transactions that have become processable from the pool's
+// queue to the set of pending transactions.
 func (pool *TxPool) checkQueue() {
-	// init delayed since tx pool could have been started before any state sync
+	// Init delayed since tx pool could have been started before any state sync
 	if pool.pendingState == nil {
 		pool.resetState()
 	}
@@ -473,17 +497,19 @@ func (pool *TxPool) checkQueue() {
 			trueNonce    = currentState.GetNonce(address)      // nonce known by the last state
 		)
 		promote = promote[:0]
-		for hash, tx := range txs {
+		for nonce, tx := range txs {
 			// Drop processed or out of fund transactions
-			if tx.Nonce() < trueNonce || balance.Cmp(tx.Cost()) < 0 {
+			if nonce < trueNonce || balance.Cmp(tx.Cost()) < 0 {
 				if glog.V(logger.Core) {
 					glog.Infof("removed tx (%v) from pool queue: low tx nonce or out of funds\n", tx)
 				}
-				delete(txs, hash)
+				delete(txs, nonce)
+				delete(pool.all, tx.Hash())
+
 				continue
 			}
 			// Collect the remaining transactions for the next pass.
-			promote = append(promote, txQueueEntry{hash, address, tx})
+			promote = append(promote, txQueueEntry{address, tx})
 		}
 		// Find the next consecutive nonce range starting at the current account nonce,
 		// pushing the guessed nonce forward if we add consecutive transactions.
@@ -493,17 +519,18 @@ func (pool *TxPool) checkQueue() {
 			if entry.Nonce() > guessedNonce {
 				if len(promote)-i > maxQueued {
 					if glog.V(logger.Debug) {
-						glog.Infof("Queued tx limit exceeded for %s. Tx %s removed\n", common.PP(address[:]), common.PP(entry.hash[:]))
+						glog.Infof("Queued tx limit exceeded for %s. Tx %s removed\n", common.PP(address[:]), common.PP(entry.Hash().Bytes()))
 					}
 					for _, drop := range promote[i+maxQueued:] {
-						delete(txs, drop.hash)
+						delete(txs, drop.Nonce())
+						delete(pool.all, drop.Hash())
 					}
 				}
 				break
 			}
 			// Otherwise promote the transaction and move the guess nonce if needed
-			pool.addTx(entry.hash, address, entry.Transaction)
-			delete(txs, entry.hash)
+			pool.addTx(address, entry.Transaction)
+			delete(txs, entry.Nonce())
 
 			if entry.Nonce() == guessedNonce {
 				guessedNonce++
@@ -532,40 +559,48 @@ func (pool *TxPool) validatePool() {
 	// Clean up the pending pool, accumulating invalid nonces
 	gaps := make(map[common.Address]uint64)
 
-	for hash, tx := range pool.pending {
-		sender, _ := tx.From() // err already checked
-
-		// Perform light nonce and balance validation
-		balance := balanceCache[sender]
-		if balance == nil {
-			balance = state.GetBalance(sender)
-			balanceCache[sender] = balance
-		}
-		if past := state.GetNonce(sender) > tx.Nonce(); past || balance.Cmp(tx.Cost()) < 0 {
-			// Remove an already past it invalidated transaction
-			if glog.V(logger.Core) {
-				glog.Infof("removed tx (%v) from pool: low tx nonce or out of funds\n", tx)
+	for addr, txs := range pool.pending {
+		for nonce, tx := range txs {
+			// Perform light nonce and balance validation
+			balance := balanceCache[addr]
+			if balance == nil {
+				balance = state.GetBalance(addr)
+				balanceCache[addr] = balance
 			}
-			delete(pool.pending, hash)
+			if past := state.GetNonce(addr) > nonce; past || balance.Cmp(tx.Cost()) < 0 {
+				// Remove an already past it invalidated transaction
+				if glog.V(logger.Core) {
+					glog.Infof("removed tx (%v) from pool: low tx nonce or out of funds\n", tx)
+				}
+				delete(pool.pending[addr], nonce)
+				if len(pool.pending[addr]) == 0 {
+					delete(pool.pending, addr)
+				}
+				delete(pool.all, tx.Hash())
 
-			// Track the smallest invalid nonce to postpone subsequent transactions
-			if !past {
-				if prev, ok := gaps[sender]; !ok || tx.Nonce() < prev {
-					gaps[sender] = tx.Nonce()
+				// Track the smallest invalid nonce to postpone subsequent transactions
+				if !past {
+					if prev, ok := gaps[addr]; !ok || nonce < prev {
+						gaps[addr] = nonce
+					}
 				}
 			}
 		}
 	}
 	// Move all transactions after a gap back to the future queue
 	if len(gaps) > 0 {
-		for hash, tx := range pool.pending {
-			sender, _ := tx.From()
-			if gap, ok := gaps[sender]; ok && tx.Nonce() >= gap {
-				if glog.V(logger.Core) {
-					glog.Infof("postponed tx (%v) due to introduced gap\n", tx)
+		for addr, txs := range pool.pending {
+			for nonce, tx := range txs {
+				if gap, ok := gaps[addr]; ok && nonce >= gap {
+					if glog.V(logger.Core) {
+						glog.Infof("postponed tx (%v) due to introduced gap\n", tx)
+					}
+					delete(pool.pending[addr], nonce)
+					if len(pool.pending[addr]) == 0 {
+						delete(pool.pending, addr)
+					}
+					pool.queueTx(tx.Hash(), tx)
 				}
-				pool.queueTx(hash, tx)
-				delete(pool.pending, hash)
 			}
 		}
 	}
@@ -574,7 +609,6 @@ func (pool *TxPool) validatePool() {
 type txQueue []txQueueEntry
 
 type txQueueEntry struct {
-	hash common.Hash
 	addr common.Address
 	*types.Transaction
 }
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index ed9bea75f..8aa69233d 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -103,7 +103,7 @@ func TestTransactionQueue(t *testing.T) {
 	currentState.SetNonce(from, 2)
 	pool.queueTx(tx.Hash(), tx)
 	pool.checkQueue()
-	if _, ok := pool.pending[tx.Hash()]; ok {
+	if _, ok := pool.pending[from][tx.Nonce()]; ok {
 		t.Error("expected transaction to be in tx pool")
 	}
 
@@ -139,7 +139,7 @@ func TestRemoveTx(t *testing.T) {
 	currentState, _ := pool.currentState()
 	currentState.AddBalance(from, big.NewInt(1))
 	pool.queueTx(tx.Hash(), tx)
-	pool.addTx(tx.Hash(), from, tx)
+	pool.addTx(from, tx)
 	if len(pool.queue) != 1 {
 		t.Error("expected queue to be 1, got", len(pool.queue))
 	}
@@ -210,18 +210,38 @@ func TestTransactionDoubleNonce(t *testing.T) {
 	}
 	resetState()
 
-	tx := transaction(0, big.NewInt(100000), key)
-	tx2 := transaction(0, big.NewInt(1000000), key)
-	if err := pool.add(tx); err != nil {
+	tx1, _ := types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(100000), big.NewInt(1), nil).SignECDSA(key)
+	tx2, _ := types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(1000000), big.NewInt(2), nil).SignECDSA(key)
+	tx3, _ := types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(1000000), big.NewInt(1), nil).SignECDSA(key)
+
+	// Add the first two transaction, ensure higher priced stays only
+	if err := pool.add(tx1); err != nil {
 		t.Error("didn't expect error", err)
 	}
 	if err := pool.add(tx2); err != nil {
 		t.Error("didn't expect error", err)
 	}
-
 	pool.checkQueue()
-	if len(pool.pending) != 2 {
-		t.Error("expected 2 pending txs. Got", len(pool.pending))
+	if len(pool.pending[addr]) != 1 {
+		t.Error("expected 1 pending transactions, got", len(pool.pending))
+	}
+	if tx := pool.pending[addr][0]; tx.Hash() != tx2.Hash() {
+		t.Errorf("transaction mismatch: have %x, want %x", tx.Hash(), tx2.Hash())
+	}
+	// Add the thid transaction and ensure it's not saved (smaller price)
+	if err := pool.add(tx3); err != nil {
+		t.Error("didn't expect error", err)
+	}
+	pool.checkQueue()
+	if len(pool.pending[addr]) != 1 {
+		t.Error("expected 1 pending transactions, got", len(pool.pending))
+	}
+	if tx := pool.pending[addr][0]; tx.Hash() != tx2.Hash() {
+		t.Errorf("transaction mismatch: have %x, want %x", tx.Hash(), tx2.Hash())
+	}
+	// Ensure the total transaction count is correct
+	if len(pool.all) != 1 {
+		t.Error("expected 1 total transactions, got", len(pool.all))
 	}
 }
 
@@ -234,12 +254,15 @@ func TestMissingNonce(t *testing.T) {
 	if err := pool.add(tx); err != nil {
 		t.Error("didn't expect error", err)
 	}
-	if len(pool.pending) != 0 {
-		t.Error("expected 0 pending transactions, got", len(pool.pending))
+	if len(pool.pending[addr]) != 0 {
+		t.Error("expected 0 pending transactions, got", len(pool.pending[addr]))
 	}
 	if len(pool.queue[addr]) != 1 {
 		t.Error("expected 1 queued transaction, got", len(pool.queue[addr]))
 	}
+	if len(pool.all) != 1 {
+		t.Error("expected 1 total transactions, got", len(pool.all))
+	}
 }
 
 func TestNonceRecovery(t *testing.T) {
@@ -270,8 +293,11 @@ func TestRemovedTxEvent(t *testing.T) {
 	currentState.AddBalance(from, big.NewInt(1000000000000))
 	pool.eventMux.Post(RemovedTransactionEvent{types.Transactions{tx}})
 	pool.eventMux.Post(ChainHeadEvent{nil})
-	if len(pool.pending) != 1 {
-		t.Error("expected 1 pending tx, got", len(pool.pending))
+	if len(pool.pending[from]) != 1 {
+		t.Error("expected 1 pending tx, got", len(pool.pending[from]))
+	}
+	if len(pool.all) != 1 {
+		t.Error("expected 1 total transactions, got", len(pool.all))
 	}
 }
 
@@ -292,41 +318,50 @@ func TestTransactionDropping(t *testing.T) {
 		tx10 = transaction(10, big.NewInt(100), key)
 		tx11 = transaction(11, big.NewInt(200), key)
 	)
-	pool.addTx(tx0.Hash(), account, tx0)
-	pool.addTx(tx1.Hash(), account, tx1)
+	pool.addTx(account, tx0)
+	pool.addTx(account, tx1)
 	pool.queueTx(tx10.Hash(), tx10)
 	pool.queueTx(tx11.Hash(), tx11)
 
 	// Check that pre and post validations leave the pool as is
-	if len(pool.pending) != 2 {
-		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending), 2)
+	if len(pool.pending[account]) != 2 {
+		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending[account]), 2)
 	}
 	if len(pool.queue[account]) != 2 {
-		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue), 2)
+		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue[account]), 2)
+	}
+	if len(pool.all) != 4 {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 4)
 	}
 	pool.resetState()
-	if len(pool.pending) != 2 {
-		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending), 2)
+	if len(pool.pending[account]) != 2 {
+		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending[account]), 2)
 	}
 	if len(pool.queue[account]) != 2 {
-		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue), 2)
+		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue[account]), 2)
+	}
+	if len(pool.all) != 4 {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 4)
 	}
 	// Reduce the balance of the account, and check that invalidated transactions are dropped
 	state.AddBalance(account, big.NewInt(-750))
 	pool.resetState()
 
-	if _, ok := pool.pending[tx0.Hash()]; !ok {
+	if _, ok := pool.pending[account][tx0.Nonce()]; !ok {
 		t.Errorf("funded pending transaction missing: %v", tx0)
 	}
-	if _, ok := pool.pending[tx1.Hash()]; ok {
+	if _, ok := pool.pending[account][tx1.Nonce()]; ok {
 		t.Errorf("out-of-fund pending transaction present: %v", tx1)
 	}
-	if _, ok := pool.queue[account][tx10.Hash()]; !ok {
+	if _, ok := pool.queue[account][tx10.Nonce()]; !ok {
 		t.Errorf("funded queued transaction missing: %v", tx10)
 	}
-	if _, ok := pool.queue[account][tx11.Hash()]; ok {
+	if _, ok := pool.queue[account][tx11.Nonce()]; ok {
 		t.Errorf("out-of-fund queued transaction present: %v", tx11)
 	}
+	if len(pool.all) != 2 {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 2)
+	}
 }
 
 // Tests that if a transaction is dropped from the current pending pool (e.g. out
@@ -349,50 +384,59 @@ func TestTransactionPostponing(t *testing.T) {
 		} else {
 			tx = transaction(uint64(i), big.NewInt(500), key)
 		}
-		pool.addTx(tx.Hash(), account, tx)
+		pool.addTx(account, tx)
 		txns = append(txns, tx)
 	}
 	// Check that pre and post validations leave the pool as is
-	if len(pool.pending) != len(txns) {
-		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending), len(txns))
+	if len(pool.pending[account]) != len(txns) {
+		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending[account]), len(txns))
 	}
 	if len(pool.queue[account]) != 0 {
-		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue), 0)
+		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue[account]), 0)
+	}
+	if len(pool.all) != len(txns) {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txns))
 	}
 	pool.resetState()
-	if len(pool.pending) != len(txns) {
-		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending), len(txns))
+	if len(pool.pending[account]) != len(txns) {
+		t.Errorf("pending transaction mismatch: have %d, want %d", len(pool.pending[account]), len(txns))
 	}
 	if len(pool.queue[account]) != 0 {
-		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue), 0)
+		t.Errorf("queued transaction mismatch: have %d, want %d", len(pool.queue[account]), 0)
+	}
+	if len(pool.all) != len(txns) {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txns))
 	}
 	// Reduce the balance of the account, and check that transactions are reorganised
 	state.AddBalance(account, big.NewInt(-750))
 	pool.resetState()
 
-	if _, ok := pool.pending[txns[0].Hash()]; !ok {
+	if _, ok := pool.pending[account][txns[0].Nonce()]; !ok {
 		t.Errorf("tx %d: valid and funded transaction missing from pending pool: %v", 0, txns[0])
 	}
-	if _, ok := pool.queue[account][txns[0].Hash()]; ok {
+	if _, ok := pool.queue[account][txns[0].Nonce()]; ok {
 		t.Errorf("tx %d: valid and funded transaction present in future queue: %v", 0, txns[0])
 	}
 	for i, tx := range txns[1:] {
 		if i%2 == 1 {
-			if _, ok := pool.pending[tx.Hash()]; ok {
+			if _, ok := pool.pending[account][tx.Nonce()]; ok {
 				t.Errorf("tx %d: valid but future transaction present in pending pool: %v", i+1, tx)
 			}
-			if _, ok := pool.queue[account][tx.Hash()]; !ok {
+			if _, ok := pool.queue[account][tx.Nonce()]; !ok {
 				t.Errorf("tx %d: valid but future transaction missing from future queue: %v", i+1, tx)
 			}
 		} else {
-			if _, ok := pool.pending[tx.Hash()]; ok {
+			if _, ok := pool.pending[account][tx.Nonce()]; ok {
 				t.Errorf("tx %d: out-of-fund transaction present in pending pool: %v", i+1, tx)
 			}
-			if _, ok := pool.queue[account][tx.Hash()]; ok {
+			if _, ok := pool.queue[account][tx.Nonce()]; ok {
 				t.Errorf("tx %d: out-of-fund transaction present in future queue: %v", i+1, tx)
 			}
 		}
 	}
+	if len(pool.all) != len(txns)/2 {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txns)/2)
+	}
 }
 
 // Tests that if the transaction count belonging to a single account goes above
@@ -423,6 +467,9 @@ func TestTransactionQueueLimiting(t *testing.T) {
 			}
 		}
 	}
+	if len(pool.all) != maxQueued {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), maxQueued)
+	}
 }
 
 // Tests that even if the transaction count belonging to a single account goes
@@ -441,13 +488,16 @@ func TestTransactionPendingLimiting(t *testing.T) {
 		if err := pool.Add(transaction(i, big.NewInt(100000), key)); err != nil {
 			t.Fatalf("tx %d: failed to add transaction: %v", i, err)
 		}
-		if len(pool.pending) != int(i)+1 {
-			t.Errorf("tx %d: pending pool size mismatch: have %d, want %d", i, len(pool.pending), i+1)
+		if len(pool.pending[account]) != int(i)+1 {
+			t.Errorf("tx %d: pending pool size mismatch: have %d, want %d", i, len(pool.pending[account]), i+1)
 		}
 		if len(pool.queue[account]) != 0 {
 			t.Errorf("tx %d: queue size mismatch: have %d, want %d", i, len(pool.queue[account]), 0)
 		}
 	}
+	if len(pool.all) != maxQueued+5 {
+		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), maxQueued+5)
+	}
 }
 
 // Tests that the transaction limits are enforced the same way irrelevant whether
@@ -486,6 +536,9 @@ func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
 	if len(pool1.queue[account1]) != len(pool2.queue[account2]) {
 		t.Errorf("queued transaction count mismatch: one-by-one algo: %d, batch algo: %d", len(pool1.queue[account1]), len(pool2.queue[account2]))
 	}
+	if len(pool1.all) != len(pool2.all) {
+		t.Errorf("total transaction count mismatch: one-by-one algo %d, batch algo %d", len(pool1.all), len(pool2.all))
+	}
 }
 
 // Benchmarks the speed of validating the contents of the pending queue of the
@@ -503,7 +556,7 @@ func benchmarkValidatePool(b *testing.B, size int) {
 
 	for i := 0; i < size; i++ {
 		tx := transaction(uint64(i), big.NewInt(100000), key)
-		pool.addTx(tx.Hash(), account, tx)
+		pool.addTx(account, tx)
 	}
 	// Benchmark the speed of pool validation
 	b.ResetTimer()
diff --git a/eth/api_backend.go b/eth/api_backend.go
index efcdb3361..e19254374 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -149,7 +149,7 @@ func (b *EthApiBackend) Stats() (pending int, queued int) {
 	return b.eth.txPool.Stats()
 }
 
-func (b *EthApiBackend) TxPoolContent() (map[common.Address]map[uint64][]*types.Transaction, map[common.Address]map[uint64][]*types.Transaction) {
+func (b *EthApiBackend) TxPoolContent() (map[common.Address]core.TxList, map[common.Address]core.TxList) {
 	b.eth.txMu.Lock()
 	defer b.eth.txMu.Unlock()
 
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 184b5831f..0fba55ae8 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -100,32 +100,26 @@ func NewPublicTxPoolAPI(b Backend) *PublicTxPoolAPI {
 }
 
 // Content returns the transactions contained within the transaction pool.
-func (s *PublicTxPoolAPI) Content() map[string]map[string]map[string][]*RPCTransaction {
-	content := map[string]map[string]map[string][]*RPCTransaction{
-		"pending": make(map[string]map[string][]*RPCTransaction),
-		"queued":  make(map[string]map[string][]*RPCTransaction),
+func (s *PublicTxPoolAPI) Content() map[string]map[string]map[string]*RPCTransaction {
+	content := map[string]map[string]map[string]*RPCTransaction{
+		"pending": make(map[string]map[string]*RPCTransaction),
+		"queued":  make(map[string]map[string]*RPCTransaction),
 	}
 	pending, queue := s.b.TxPoolContent()
 
 	// Flatten the pending transactions
-	for account, batches := range pending {
-		dump := make(map[string][]*RPCTransaction)
-		for nonce, txs := range batches {
-			nonce := fmt.Sprintf("%d", nonce)
-			for _, tx := range txs {
-				dump[nonce] = append(dump[nonce], newRPCPendingTransaction(tx))
-			}
+	for account, txs := range pending {
+		dump := make(map[string]*RPCTransaction)
+		for nonce, tx := range txs {
+			dump[fmt.Sprintf("%d", nonce)] = newRPCPendingTransaction(tx)
 		}
 		content["pending"][account.Hex()] = dump
 	}
 	// Flatten the queued transactions
-	for account, batches := range queue {
-		dump := make(map[string][]*RPCTransaction)
-		for nonce, txs := range batches {
-			nonce := fmt.Sprintf("%d", nonce)
-			for _, tx := range txs {
-				dump[nonce] = append(dump[nonce], newRPCPendingTransaction(tx))
-			}
+	for account, txs := range queue {
+		dump := make(map[string]*RPCTransaction)
+		for nonce, tx := range txs {
+			dump[fmt.Sprintf("%d", nonce)] = newRPCPendingTransaction(tx)
 		}
 		content["queued"][account.Hex()] = dump
 	}
@@ -143,10 +137,10 @@ func (s *PublicTxPoolAPI) Status() map[string]*rpc.HexNumber {
 
 // Inspect retrieves the content of the transaction pool and flattens it into an
 // easily inspectable list.
-func (s *PublicTxPoolAPI) Inspect() map[string]map[string]map[string][]string {
-	content := map[string]map[string]map[string][]string{
-		"pending": make(map[string]map[string][]string),
-		"queued":  make(map[string]map[string][]string),
+func (s *PublicTxPoolAPI) Inspect() map[string]map[string]map[string]string {
+	content := map[string]map[string]map[string]string{
+		"pending": make(map[string]map[string]string),
+		"queued":  make(map[string]map[string]string),
 	}
 	pending, queue := s.b.TxPoolContent()
 
@@ -158,24 +152,18 @@ func (s *PublicTxPoolAPI) Inspect() map[string]map[string]map[string][]string {
 		return fmt.Sprintf("contract creation: %v wei + %v × %v gas", tx.Value(), tx.Gas(), tx.GasPrice())
 	}
 	// Flatten the pending transactions
-	for account, batches := range pending {
-		dump := make(map[string][]string)
-		for nonce, txs := range batches {
-			nonce := fmt.Sprintf("%d", nonce)
-			for _, tx := range txs {
-				dump[nonce] = append(dump[nonce], format(tx))
-			}
+	for account, txs := range pending {
+		dump := make(map[string]string)
+		for nonce, tx := range txs {
+			dump[fmt.Sprintf("%d", nonce)] = format(tx)
 		}
 		content["pending"][account.Hex()] = dump
 	}
 	// Flatten the queued transactions
-	for account, batches := range queue {
-		dump := make(map[string][]string)
-		for nonce, txs := range batches {
-			nonce := fmt.Sprintf("%d", nonce)
-			for _, tx := range txs {
-				dump[nonce] = append(dump[nonce], format(tx))
-			}
+	for account, txs := range queue {
+		dump := make(map[string]string)
+		for nonce, tx := range txs {
+			dump[fmt.Sprintf("%d", nonce)] = format(tx)
 		}
 		content["queued"][account.Hex()] = dump
 	}
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index 791a06925..673ab0546 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -58,7 +58,7 @@ type Backend interface {
 	GetPoolTransaction(txHash common.Hash) *types.Transaction
 	GetPoolNonce(ctx context.Context, addr common.Address) (uint64, error)
 	Stats() (pending int, queued int)
-	TxPoolContent() (map[common.Address]map[uint64][]*types.Transaction, map[common.Address]map[uint64][]*types.Transaction)
+	TxPoolContent() (map[common.Address]core.TxList, map[common.Address]core.TxList)
 }
 
 type State interface {
diff --git a/miner/worker.go b/miner/worker.go
index 59406bf4e..f243fe799 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -68,12 +68,12 @@ type Work struct {
 	ancestors          *set.Set       // ancestor set (used for checking uncle parent validity)
 	family             *set.Set       // family set (used for checking uncle invalidity)
 	uncles             *set.Set       // uncle set
-	remove             *set.Set       // tx which will be removed
 	tcount             int            // tx count in cycle
 	ignoredTransactors *set.Set
 	lowGasTransactors  *set.Set
 	ownedAccounts      *set.Set
 	lowGasTxs          types.Transactions
+	failedTxs          types.Transactions
 	localMinedBlocks   *uint64RingBuffer // the most recent block numbers that were mined locally (used to check block inclusion)
 
 	Block *types.Block // the new block
@@ -383,7 +383,6 @@ func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error
 	accounts := self.eth.AccountManager().Accounts()
 
 	// Keep track of transactions which return errors so they can be removed
-	work.remove = set.New()
 	work.tcount = 0
 	work.ignoredTransactors = set.New()
 	work.lowGasTransactors = set.New()
@@ -533,7 +532,9 @@ func (self *worker) commitNewWork() {
 	*/
 
 	work.commitTransactions(self.mux, transactions, self.gasPrice, self.chain)
+
 	self.eth.TxPool().RemoveTransactions(work.lowGasTxs)
+	self.eth.TxPool().RemoveTransactions(work.failedTxs)
 
 	// compute uncles for the new block.
 	var (
@@ -639,11 +640,10 @@ func (env *Work) commitTransactions(mux *event.TypeMux, transactions types.Trans
 			// ignore the transactor so no nonce errors will be thrown for this account
 			// next time the worker is run, they'll be picked up again.
 			env.ignoredTransactors.Add(from)
-
 			glog.V(logger.Detail).Infof("Gas limit reached for (%x) in this block. Continue to try smaller txs\n", from[:4])
-		case err != nil:
-			env.remove.Add(tx.Hash())
 
+		case err != nil:
+			env.failedTxs = append(env.failedTxs, tx)
 			if glog.V(logger.Detail) {
 				glog.Infof("TX (%x) failed, will be removed: %v\n", tx.Hash().Bytes()[:4], err)
 			}