Merge branch 'master' into miner-no-default

Conflicts: sync/src/lib.rs
2016-06-23 21:04:23 +02:00
parent a2f24a0083 416781a8d4
commit 6edb981bfa
160 changed files with 29723 additions and 918 deletions
--- a/ethcore/Cargo.toml
+++ b/ethcore/Cargo.toml
@@ -22,7 +22,7 @@ ethcore-util = { path = "../util" }
 evmjit = { path = "../evmjit", optional = true }
 ethash = { path = "../ethash" }
 num_cpus = "0.2"
-clippy = { version = "0.0.76", optional = true}
+clippy = { version = "0.0.77", optional = true}
 crossbeam = "0.2.9"
 lazy_static = "0.2"
 ethcore-devtools = { path = "../devtools" }
--- a/ethcore/res/ethereum/frontier.json
+++ b/ethcore/res/ethereum/frontier.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x0d",
 				"blockReward": "0x4563918244F40000",
 				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
-				"frontierCompatibilityModeLimit": "0x118c30"
+				"frontierCompatibilityModeLimit": "0x118c30",
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/res/ethereum/frontier_dao_rescue.json
+++ b/ethcore/res/ethereum/frontier_dao_rescue.json
--- a/ethcore/res/ethereum/frontier_like_test.json
+++ b/ethcore/res/ethereum/frontier_like_test.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x0d",
 				"blockReward": "0x4563918244F40000",
 				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
-				"frontierCompatibilityModeLimit": "0x118c30"
+				"frontierCompatibilityModeLimit": "0x118c30",
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/res/ethereum/frontier_like_test_dao_rescue.json
+++ b/ethcore/res/ethereum/frontier_like_test_dao_rescue.json
@@ -0,0 +1,43 @@
+{
+	"name": "Frontier (Test)",
+	"engine": {
+		"Ethash": {
+			"params": {
+				"gasLimitBoundDivisor": "0x0400",
+				"minimumDifficulty": "0x020000",
+				"difficultyBoundDivisor": "0x0800",
+				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
+				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
+				"frontierCompatibilityModeLimit": "0x118c30",
+				"daoRescueSoftFork": true
+			}
+		}
+	},
+	"params": {
+		"accountStartNonce": "0x00",
+		"maximumExtraDataSize": "0x20",
+		"minGasLimit": "0x1388",
+		"networkID" : "0x1"
+	},
+	"genesis": {
+		"seal": {
+			"ethereum": {
+				"nonce": "0x0000000000000042",
+				"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
+			}
+		},
+		"difficulty": "0x400000000",
+		"author": "0x0000000000000000000000000000000000000000",
+		"timestamp": "0x00",
+		"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+		"extraData": "0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa",
+		"gasLimit": "0x1388"
+	},
+	"accounts": {
+		"0000000000000000000000000000000000000001": { "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
+		"0000000000000000000000000000000000000002": { "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
+		"0000000000000000000000000000000000000003": { "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
+		"0000000000000000000000000000000000000004": { "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } }
+	}
+}
--- a/ethcore/res/ethereum/frontier_test.json
+++ b/ethcore/res/ethereum/frontier_test.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x0d",
 				"blockReward": "0x4563918244F40000",
 				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
-				"frontierCompatibilityModeLimit": "0xffffffffffffffff"
+				"frontierCompatibilityModeLimit": "0xffffffffffffffff",
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/res/ethereum/homestead_test.json
+++ b/ethcore/res/ethereum/homestead_test.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x0d",
 				"blockReward": "0x4563918244F40000",
 				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
-				"frontierCompatibilityModeLimit": 0
+				"frontierCompatibilityModeLimit": 0,
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/res/ethereum/homestead_test_dao_rescue.json
+++ b/ethcore/res/ethereum/homestead_test_dao_rescue.json
@@ -0,0 +1,43 @@
+{
+	"name": "Homestead (Test)",
+	"engine": {
+		"Ethash": {
+			"params": {
+				"gasLimitBoundDivisor": "0x0400",
+				"minimumDifficulty": "0x020000",
+				"difficultyBoundDivisor": "0x0800",
+				"durationLimit": "0x0d",
+				"blockReward": "0x4563918244F40000",
+				"registrar" : "0xc6d9d2cd449a754c494264e1809c50e34d64562b",
+				"frontierCompatibilityModeLimit": 0,
+				"daoRescueSoftFork": true
+			}
+		}
+	},
+	"params": {
+		"accountStartNonce": "0x00",
+		"maximumExtraDataSize": "0x20",
+		"minGasLimit": "0x1388",
+		"networkID" : "0x1"
+	},
+	"genesis": {
+		"seal": {
+			"ethereum": {
+				"nonce": "0x0000000000000042",
+				"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
+			}
+		},
+		"difficulty": "0x400000000",
+		"author": "0x0000000000000000000000000000000000000000",
+		"timestamp": "0x00",
+		"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+		"extraData": "0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa",
+		"gasLimit": "0x1388"
+	},
+	"accounts": {
+		"0000000000000000000000000000000000000001": { "balance": "1", "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
+		"0000000000000000000000000000000000000002": { "balance": "1", "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
+		"0000000000000000000000000000000000000003": { "balance": "1", "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
+		"0000000000000000000000000000000000000004": { "balance": "1", "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } }
+	}
+}
--- a/ethcore/res/ethereum/morden.json
+++ b/ethcore/res/ethereum/morden.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x0d",
 				"blockReward": "0x4563918244F40000",
 				"registrar": "",
-				"frontierCompatibilityModeLimit": "0x789b0"
+				"frontierCompatibilityModeLimit": "0x789b0",
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/res/ethereum/olympic.json
+++ b/ethcore/res/ethereum/olympic.json
@@ -9,7 +9,8 @@
 				"durationLimit": "0x08",
 				"blockReward": "0x14D1120D7B160000",
 				"registrar": "5e70c0bbcd5636e0f9f9316e9f8633feb64d4050",
-				"frontierCompatibilityModeLimit": "0xffffffffffffffff"
+				"frontierCompatibilityModeLimit": "0xffffffffffffffff",
+				"daoRescueSoftFork": false
 			}
 		}
 	},
--- a/ethcore/src/account.rs
+++ b/ethcore/src/account.rs
@@ -166,16 +166,16 @@ impl Account {
 		!self.code_cache.is_empty() || (self.code_cache.is_empty() && self.code_hash == Some(SHA3_EMPTY))
 	}

-	/// Provide a database to lookup `code_hash`. Should not be called if it is a contract without code.
+	/// Provide a database to get `code_hash`. Should not be called if it is a contract without code.
 	pub fn cache_code(&mut self, db: &AccountDB) -> bool {
 		// TODO: fill out self.code_cache;
 		trace!("Account::cache_code: ic={}; self.code_hash={:?}, self.code_cache={}", self.is_cached(), self.code_hash, self.code_cache.pretty());
 		self.is_cached() ||
 			match self.code_hash {
-				Some(ref h) => match db.lookup(h) {
+				Some(ref h) => match db.get(h) {
 					Some(x) => { self.code_cache = x.to_vec(); true },
 					_ => {
-						warn!("Failed reverse lookup of {}", h);
+						warn!("Failed reverse get of {}", h);
 						false
 					},
 				},
--- a/ethcore/src/account_db.rs
+++ b/ethcore/src/account_db.rs
@@ -30,18 +30,18 @@ impl<'db> HashDB for AccountDB<'db>{
 		unimplemented!()
 	}

-	fn lookup(&self, key: &H256) -> Option<&[u8]> {
+	fn get(&self, key: &H256) -> Option<&[u8]> {
 		if key == &SHA3_NULL_RLP {
 			return Some(&NULL_RLP_STATIC);
 		}
-		self.db.lookup(&combine_key(&self.address, key))
+		self.db.get(&combine_key(&self.address, key))
 	}

-	fn exists(&self, key: &H256) -> bool {
+	fn contains(&self, key: &H256) -> bool {
 		if key == &SHA3_NULL_RLP {
 			return true;
 		}
-		self.db.exists(&combine_key(&self.address, key))
+		self.db.contains(&combine_key(&self.address, key))
 	}

 	fn insert(&mut self, _value: &[u8]) -> H256 {
@@ -52,7 +52,7 @@ impl<'db> HashDB for AccountDB<'db>{
 		unimplemented!()
 	}

-	fn kill(&mut self, _key: &H256) {
+	fn remove(&mut self, _key: &H256) {
 		unimplemented!()
 	}
 }
@@ -82,18 +82,18 @@ impl<'db> HashDB for AccountDBMut<'db>{
 		unimplemented!()
 	}

-	fn lookup(&self, key: &H256) -> Option<&[u8]> {
+	fn get(&self, key: &H256) -> Option<&[u8]> {
 		if key == &SHA3_NULL_RLP {
 			return Some(&NULL_RLP_STATIC);
 		}
-		self.db.lookup(&combine_key(&self.address, key))
+		self.db.get(&combine_key(&self.address, key))
 	}

-	fn exists(&self, key: &H256) -> bool {
+	fn contains(&self, key: &H256) -> bool {
 		if key == &SHA3_NULL_RLP {
 			return true;
 		}
-		self.db.exists(&combine_key(&self.address, key))
+		self.db.contains(&combine_key(&self.address, key))
 	}

 	fn insert(&mut self, value: &[u8]) -> H256 {
@@ -114,12 +114,12 @@ impl<'db> HashDB for AccountDBMut<'db>{
 		self.db.emplace(key, value.to_vec())
 	}

-	fn kill(&mut self, key: &H256) {
+	fn remove(&mut self, key: &H256) {
 		if key == &SHA3_NULL_RLP {
 			return;
 		}
 		let key = combine_key(&self.address, key);
-		self.db.kill(&key)
+		self.db.remove(&key)
 	}
 }

--- a/ethcore/src/account_provider.rs
+++ b/ethcore/src/account_provider.rs
@@ -205,6 +205,13 @@ impl AccountProvider {
 		self.unlock_account(account, password, Unlock::Temp)
 	}

+	/// Checks if given account is unlocked
+	pub fn is_unlocked<A>(&self, account: A) -> bool where Address: From<A> {
+		let account = Address::from(account).into();
+		let unlocked = self.unlocked.read().unwrap();
+		unlocked.get(&account).is_some()
+	}
+
 	/// Signs the message. Account must be unlocked.
 	pub fn sign<A, M>(&self, account: A, message: M) -> Result<H520, Error> where Address: From<A>, Message: From<M> {
 		let account = Address::from(account).into();
@@ -236,7 +243,6 @@ impl AccountProvider {
 #[cfg(test)]
 mod tests {
 	use super::AccountProvider;
-	use ethstore::SecretStore;
 	use ethstore::ethkey::{Generator, Random};

 	#[test]
--- a/ethcore/src/basic_authority.rs
+++ b/ethcore/src/basic_authority.rs
@@ -203,8 +203,9 @@ mod tests {
 			timestamp: 0,
 			difficulty: 0.into(),
 			last_hashes: vec![],
+			dao_rescue_block_gas_limit: None,
 			gas_used: 0.into(),
-			gas_limit: 0.into()
+			gas_limit: 0.into(),
 		});

 		assert!(schedule.stack_limit > 0);
@@ -253,7 +254,7 @@ mod tests {
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let last_hashes = vec![genesis_header.hash()];
 		let vm_factory = Default::default();
-		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, addr, 3141562.into(), vec![]).unwrap();
+		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, None, addr, 3141562.into(), vec![]).unwrap();
 		let b = b.close_and_lock();
 		let seal = engine.generate_seal(b.block(), Some(&tap)).unwrap();
 		assert!(b.try_seal(engine.deref(), seal).is_ok());
--- a/ethcore/src/block.rs
+++ b/ethcore/src/block.rs
@@ -177,6 +177,7 @@ pub struct OpenBlock<'x> {
 	engine: &'x Engine,
 	vm_factory: &'x EvmFactory,
 	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
 }

 /// Just like `OpenBlock`, except that we've applied `Engine::on_close_block`, finished up the non-seal header fields,
@@ -188,6 +189,7 @@ pub struct ClosedBlock {
 	block: ExecutedBlock,
 	uncle_bytes: Bytes,
 	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
 	unclosed_state: State,
 }

@@ -198,7 +200,6 @@ pub struct ClosedBlock {
 pub struct LockedBlock {
 	block: ExecutedBlock,
 	uncle_bytes: Bytes,
-	last_hashes: LastHashes,
 }

 /// A block that has a valid seal.
@@ -219,9 +220,10 @@ impl<'x> OpenBlock<'x> {
 		db: Box<JournalDB>,
 		parent: &Header,
 		last_hashes: LastHashes,
+		dao_rescue_block_gas_limit: Option<U256>,
 		author: Address,
 		gas_floor_target: U256,
-		extra_data: Bytes
+		extra_data: Bytes,
 	) -> Result<Self, Error> {
 		let state = try!(State::from_existing(db, parent.state_root().clone(), engine.account_start_nonce()));
 		let mut r = OpenBlock {
@@ -229,6 +231,7 @@ impl<'x> OpenBlock<'x> {
 			engine: engine,
 			vm_factory: vm_factory,
 			last_hashes: last_hashes,
+			dao_rescue_block_gas_limit: dao_rescue_block_gas_limit,
 		};

 		r.block.base.header.parent_hash = parent.hash();
@@ -285,6 +288,7 @@ impl<'x> OpenBlock<'x> {
 	/// Get the environment info concerning this block.
 	pub fn env_info(&self) -> EnvInfo {
 		// TODO: memoise.
+		const SOFT_FORK_BLOCK: u64 = 1775000;
 		EnvInfo {
 			number: self.block.base.header.number,
 			author: self.block.base.header.author.clone(),
@@ -293,6 +297,7 @@ impl<'x> OpenBlock<'x> {
 			last_hashes: self.last_hashes.clone(),		// TODO: should be a reference.
 			gas_used: self.block.receipts.last().map_or(U256::zero(), |r| r.gas_used),
 			gas_limit: self.block.base.header.gas_limit.clone(),
+			dao_rescue_block_gas_limit: if self.block.base.header.number == SOFT_FORK_BLOCK { Some(self.block.base.header.gas_limit) } else { self.dao_rescue_block_gas_limit },
 		}
 	}

@@ -339,6 +344,7 @@ impl<'x> OpenBlock<'x> {
 			block: s.block,
 			uncle_bytes: uncle_bytes,
 			last_hashes: s.last_hashes,
+			dao_rescue_block_gas_limit: s.dao_rescue_block_gas_limit,
 			unclosed_state: unclosed_state,
 		}
 	}
@@ -360,7 +366,6 @@ impl<'x> OpenBlock<'x> {
 		LockedBlock {
 			block: s.block,
 			uncle_bytes: uncle_bytes,
-			last_hashes: s.last_hashes,
 		}
 	}
 }
@@ -386,7 +391,6 @@ impl ClosedBlock {
 		LockedBlock {
 			block: self.block,
 			uncle_bytes: self.uncle_bytes,
-			last_hashes: self.last_hashes,
 		}
 	}

@@ -400,6 +404,7 @@ impl ClosedBlock {
 			engine: engine,
 			vm_factory: vm_factory,
 			last_hashes: self.last_hashes,
+			dao_rescue_block_gas_limit: self.dao_rescue_block_gas_limit,
 		}
 	}
 }
@@ -456,7 +461,18 @@ impl IsBlock for SealedBlock {

 /// Enact the block given by block header, transactions and uncles
 #[cfg_attr(feature="dev", allow(too_many_arguments))]
-pub fn enact(header: &Header, transactions: &[SignedTransaction], uncles: &[Header], engine: &Engine, tracing: bool, db: Box<JournalDB>, parent: &Header, last_hashes: LastHashes, vm_factory: &EvmFactory) -> Result<LockedBlock, Error> {
+pub fn enact(
+	header: &Header,
+	transactions: &[SignedTransaction],
+	uncles: &[Header],
+	engine: &Engine,
+	tracing: bool,
+	db: Box<JournalDB>,
+	parent: &Header,
+	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
+	vm_factory: &EvmFactory
+) -> Result<LockedBlock, Error> {
 	{
 		if ::log::max_log_level() >= ::log::LogLevel::Trace {
 			let s = try!(State::from_existing(db.boxed_clone(), parent.state_root().clone(), engine.account_start_nonce()));
@@ -464,7 +480,7 @@ pub fn enact(header: &Header, transactions: &[SignedTransaction], uncles: &[Head
 		}
 	}

-	let mut b = try!(OpenBlock::new(engine, vm_factory, tracing, db, parent, last_hashes, header.author().clone(), 3141562.into(), header.extra_data().clone()));
+	let mut b = try!(OpenBlock::new(engine, vm_factory, tracing, db, parent, last_hashes, dao_rescue_block_gas_limit, header.author().clone(), 3141562.into(), header.extra_data().clone()));
 	b.set_difficulty(*header.difficulty());
 	b.set_gas_limit(*header.gas_limit());
 	b.set_timestamp(header.timestamp());
@@ -474,22 +490,52 @@ pub fn enact(header: &Header, transactions: &[SignedTransaction], uncles: &[Head
 }

 /// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header
-pub fn enact_bytes(block_bytes: &[u8], engine: &Engine, tracing: bool, db: Box<JournalDB>, parent: &Header, last_hashes: LastHashes, vm_factory: &EvmFactory) -> Result<LockedBlock, Error> {
+#[cfg_attr(feature="dev", allow(too_many_arguments))]
+pub fn enact_bytes(
+	block_bytes: &[u8],
+	engine: &Engine,
+	tracing: bool,
+	db: Box<JournalDB>,
+	parent: &Header,
+	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
+	vm_factory: &EvmFactory
+) -> Result<LockedBlock, Error> {
 	let block = BlockView::new(block_bytes);
 	let header = block.header();
-	enact(&header, &block.transactions(), &block.uncles(), engine, tracing, db, parent, last_hashes, vm_factory)
+	enact(&header, &block.transactions(), &block.uncles(), engine, tracing, db, parent, last_hashes, dao_rescue_block_gas_limit, vm_factory)
 }

 /// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header
-pub fn enact_verified(block: &PreverifiedBlock, engine: &Engine, tracing: bool, db: Box<JournalDB>, parent: &Header, last_hashes: LastHashes, vm_factory: &EvmFactory) -> Result<LockedBlock, Error> {
+#[cfg_attr(feature="dev", allow(too_many_arguments))]
+pub fn enact_verified(
+	block: &PreverifiedBlock,
+	engine: &Engine,
+	tracing: bool,
+	db: Box<JournalDB>,
+	parent: &Header,
+	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
+	vm_factory: &EvmFactory
+) -> Result<LockedBlock, Error> {
 	let view = BlockView::new(&block.bytes);
-	enact(&block.header, &block.transactions, &view.uncles(), engine, tracing, db, parent, last_hashes, vm_factory)
+	enact(&block.header, &block.transactions, &view.uncles(), engine, tracing, db, parent, last_hashes, dao_rescue_block_gas_limit, vm_factory)
 }

 /// Enact the block given by `block_bytes` using `engine` on the database `db` with given `parent` block header. Seal the block aferwards
-pub fn enact_and_seal(block_bytes: &[u8], engine: &Engine, tracing: bool, db: Box<JournalDB>, parent: &Header, last_hashes: LastHashes, vm_factory: &EvmFactory) -> Result<SealedBlock, Error> {
+#[cfg_attr(feature="dev", allow(too_many_arguments))]
+pub fn enact_and_seal(
+	block_bytes: &[u8],
+	engine: &Engine,
+	tracing: bool,
+	db: Box<JournalDB>,
+	parent: &Header,
+	last_hashes: LastHashes,
+	dao_rescue_block_gas_limit: Option<U256>,
+	vm_factory: &EvmFactory
+) -> Result<SealedBlock, Error> {
 	let header = BlockView::new(block_bytes).header_view();
-	Ok(try!(try!(enact_bytes(block_bytes, engine, tracing, db, parent, last_hashes, vm_factory)).seal(engine, header.seal())))
+	Ok(try!(try!(enact_bytes(block_bytes, engine, tracing, db, parent, last_hashes, dao_rescue_block_gas_limit, vm_factory)).seal(engine, header.seal())))
 }

 #[cfg(test)]
@@ -509,7 +555,7 @@ mod tests {
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let last_hashes = vec![genesis_header.hash()];
 		let vm_factory = Default::default();
-		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, Address::zero(), 3141562.into(), vec![]).unwrap();
+		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, None, Address::zero(), 3141562.into(), vec![]).unwrap();
 		let b = b.close_and_lock();
 		let _ = b.seal(engine.deref(), vec![]);
 	}
@@ -525,7 +571,7 @@ mod tests {
 		let mut db = db_result.take();
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let vm_factory = Default::default();
-		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, vec![genesis_header.hash()], Address::zero(), 3141562.into(), vec![]).unwrap()
+		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, vec![genesis_header.hash()], None, Address::zero(), 3141562.into(), vec![]).unwrap()
 			.close_and_lock().seal(engine.deref(), vec![]).unwrap();
 		let orig_bytes = b.rlp_bytes();
 		let orig_db = b.drain();
@@ -533,7 +579,7 @@ mod tests {
 		let mut db_result = get_temp_journal_db();
 		let mut db = db_result.take();
 		spec.ensure_db_good(db.as_hashdb_mut());
-		let e = enact_and_seal(&orig_bytes, engine.deref(), false, db, &genesis_header, vec![genesis_header.hash()], &Default::default()).unwrap();
+		let e = enact_and_seal(&orig_bytes, engine.deref(), false, db, &genesis_header, vec![genesis_header.hash()], None, &Default::default()).unwrap();

 		assert_eq!(e.rlp_bytes(), orig_bytes);

@@ -553,7 +599,7 @@ mod tests {
 		let mut db = db_result.take();
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let vm_factory = Default::default();
-		let mut open_block = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, vec![genesis_header.hash()], Address::zero(), 3141562.into(), vec![]).unwrap();
+		let mut open_block = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, vec![genesis_header.hash()], None, Address::zero(), 3141562.into(), vec![]).unwrap();
 		let mut uncle1_header = Header::new();
 		uncle1_header.extra_data = b"uncle1".to_vec();
 		let mut uncle2_header = Header::new();
@@ -568,7 +614,7 @@ mod tests {
 		let mut db_result = get_temp_journal_db();
 		let mut db = db_result.take();
 		spec.ensure_db_good(db.as_hashdb_mut());
-		let e = enact_and_seal(&orig_bytes, engine.deref(), false, db, &genesis_header, vec![genesis_header.hash()], &Default::default()).unwrap();
+		let e = enact_and_seal(&orig_bytes, engine.deref(), false, db, &genesis_header, vec![genesis_header.hash()], None, &Default::default()).unwrap();

 		let bytes = e.rlp_bytes();
 		assert_eq!(bytes, orig_bytes);
--- a/ethcore/src/block_queue.rs
+++ b/ethcore/src/block_queue.rs
@@ -130,7 +130,9 @@ impl QueueSignal {
 		}

 		if self.signalled.compare_and_swap(false, true, AtomicOrdering::Relaxed) == false {
-			self.message_channel.send(UserMessage(SyncMessage::BlockVerified)).expect("Error sending BlockVerified message");
+			if let Err(e) = self.message_channel.send(UserMessage(SyncMessage::BlockVerified)) {
+				debug!("Error sending BlockVerified message: {:?}", e);
+			}
 		}
 	}

--- a/ethcore/src/blockchain/blockchain.rs
+++ b/ethcore/src/blockchain/blockchain.rs
@@ -253,12 +253,22 @@ impl BlockChain {
 		// open extras db
 		let mut extras_path = path.to_path_buf();
 		extras_path.push("extras");
-		let extras_db = Database::open_default(extras_path.to_str().unwrap()).unwrap();
+		let extras_db = match config.db_cache_size {
+			None => Database::open_default(extras_path.to_str().unwrap()).unwrap(),
+			Some(cache_size) => Database::open(
+				&DatabaseConfig::with_cache(cache_size/2),
+				extras_path.to_str().unwrap()).unwrap(),
+		};

 		// open blocks db
 		let mut blocks_path = path.to_path_buf();
 		blocks_path.push("blocks");
-		let blocks_db = Database::open_default(blocks_path.to_str().unwrap()).unwrap();
+		let blocks_db = match config.db_cache_size {
+			None => Database::open_default(blocks_path.to_str().unwrap()).unwrap(),
+			Some(cache_size) => Database::open(
+				&DatabaseConfig::with_cache(cache_size/2),
+				blocks_path.to_str().unwrap()).unwrap(),
+		};

 		let mut cache_man = CacheManager{cache_usage: VecDeque::new(), in_use: HashSet::new()};
 		(0..COLLECTION_QUEUE_SIZE).foreach(|_| cache_man.cache_usage.push_back(HashSet::new()));
--- a/ethcore/src/blockchain/config.rs
+++ b/ethcore/src/blockchain/config.rs
@@ -23,6 +23,8 @@ pub struct Config {
 	pub pref_cache_size: usize,
 	/// Maximum cache size in bytes.
 	pub max_cache_size: usize,
+	/// Backing db cache_size
+	pub db_cache_size: Option<usize>,
 }

 impl Default for Config {
@@ -30,6 +32,7 @@ impl Default for Config {
 		Config {
 			pref_cache_size: 1 << 14,
 			max_cache_size: 1 << 20,
+			db_cache_size: None,
 		}
 	}
 }
--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@@ -18,6 +18,7 @@

 use std::marker::PhantomData;
 use std::path::PathBuf;
+use std::sync::atomic::{AtomicUsize, Ordering as AtomicOrdering};
 use util::*;
 use util::panics::*;
 use views::BlockView;
@@ -50,6 +51,8 @@ pub use types::block_status::BlockStatus;
 use evm::Factory as EvmFactory;
 use miner::{Miner, MinerService, TransactionImportResult, AccountDetails};

+const MAX_TX_QUEUE_SIZE: usize = 4096;
+
 impl fmt::Display for BlockChainInfo {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		write!(f, "#{}.{}", self.best_block_number, self.best_block_hash)
@@ -92,6 +95,8 @@ pub struct Client<V = CanonVerifier> where V: Verifier {
 	verifier: PhantomData<V>,
 	vm_factory: Arc<EvmFactory>,
 	miner: Arc<Miner>,
+	io_channel: IoChannel<NetSyncMessage>,
+	queue_transactions: AtomicUsize,
 }

 const HISTORY: u64 = 1200;
@@ -141,7 +146,10 @@ impl<V> Client<V> where V: Verifier {
 		let chain = Arc::new(BlockChain::new(config.blockchain, &gb, &path));
 		let tracedb = Arc::new(try!(TraceDB::new(config.tracing, &path, chain.clone())));

-		let mut state_db = journaldb::new(&append_path(&path, "state"), config.pruning);
+		let mut state_db = journaldb::new(
+			&append_path(&path, "state"),
+			config.pruning,
+			config.db_cache_size);

 		if state_db.is_empty() && spec.ensure_db_good(state_db.as_hashdb_mut()) {
 			state_db.commit(0, &spec.genesis_header().hash(), None).expect("Error commiting genesis state to state DB");
@@ -149,7 +157,7 @@ impl<V> Client<V> where V: Verifier {

 		let engine = Arc::new(spec.engine);

-		let block_queue = BlockQueue::new(config.queue, engine.clone(), message_channel);
+		let block_queue = BlockQueue::new(config.queue, engine.clone(), message_channel.clone());
 		let panic_handler = PanicHandler::new_in_arc();
 		panic_handler.forward_from(&block_queue);

@@ -165,6 +173,8 @@ impl<V> Client<V> where V: Verifier {
 			verifier: PhantomData,
 			vm_factory: Arc::new(EvmFactory::new(config.vm_type)),
 			miner: miner,
+			io_channel: message_channel,
+			queue_transactions: AtomicUsize::new(0),
 		};

 		Ok(Arc::new(client))
@@ -220,7 +230,7 @@ impl<V> Client<V> where V: Verifier {
 		let last_hashes = self.build_last_hashes(header.parent_hash.clone());
 		let db = self.state_db.lock().unwrap().boxed_clone();

-		let enact_result = enact_verified(&block, engine, self.tracedb.tracing_enabled(), db, &parent, last_hashes, &self.vm_factory);
+		let enact_result = enact_verified(&block, engine, self.tracedb.tracing_enabled(), db, &parent, last_hashes, self.dao_rescue_block_gas_limit(header.parent_hash.clone()), &self.vm_factory);
 		if let Err(e) = enact_result {
 			warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
 			return Err(());
@@ -271,6 +281,7 @@ impl<V> Client<V> where V: Verifier {
 		let mut import_results = Vec::with_capacity(max_blocks_to_import);

 		let _import_lock = self.import_lock.lock();
+		let _timer = PerfTimer::new("import_verified_blocks");
 		let blocks = self.block_queue.drain(max_blocks_to_import);

 		let original_best = self.chain_info().best_block_hash;
@@ -361,6 +372,19 @@ impl<V> Client<V> where V: Verifier {
 		imported
 	}

+	/// Import transactions from the IO queue
+	pub fn import_queued_transactions(&self, transactions: &[Bytes]) -> usize {
+		let _timer = PerfTimer::new("import_queued_transactions");
+		self.queue_transactions.fetch_sub(transactions.len(), AtomicOrdering::SeqCst);
+		let fetch_account = |a: &Address| AccountDetails {
+			nonce: self.latest_nonce(a),
+			balance: self.latest_balance(a),
+		};
+		let tx = transactions.iter().filter_map(|bytes| UntrustedRlp::new(&bytes).as_val().ok()).collect();
+		let results = self.miner.import_transactions(self, tx, fetch_account);
+		results.len()
+	}
+
 	/// Attempt to get a copy of a specific block's state.
 	///
 	/// This will not fail if given BlockID::Latest.
@@ -462,6 +486,7 @@ impl<V> BlockChainClient for Client<V> where V: Verifier {
 			last_hashes: last_hashes,
 			gas_used: U256::zero(),
 			gas_limit: U256::max_value(),
+			dao_rescue_block_gas_limit: self.dao_rescue_block_gas_limit(view.parent_hash()),
 		};
 		// that's just a copy of the state.
 		let mut state = self.state();
@@ -747,7 +772,23 @@ impl<V> BlockChainClient for Client<V> where V: Verifier {
 			nonce: self.latest_nonce(a),
 			balance: self.latest_balance(a),
 		};
-		self.miner.import_transactions(transactions, fetch_account)
+		self.miner.import_transactions(self, transactions, fetch_account)
+	}
+
+	fn queue_transactions(&self, transactions: Vec<Bytes>) {
+		if self.queue_transactions.load(AtomicOrdering::Relaxed) > MAX_TX_QUEUE_SIZE {
+			debug!("Ignoring {} transactions: queue is full", transactions.len());
+		} else {
+			let len = transactions.len();
+			match self.io_channel.send(NetworkIoMessage::User(SyncMessage::NewTransactions(transactions))) {
+				Ok(_) => {
+					self.queue_transactions.fetch_add(len, AtomicOrdering::SeqCst);
+				}
+				Err(e) => {
+					debug!("Ignoring {} transactions: error queueing: {}", len, e);
+				}
+			}
+		}
 	}

 	fn all_transactions(&self) -> Vec<SignedTransaction> {
@@ -767,6 +808,7 @@ impl<V> MiningBlockChainClient for Client<V> where V: Verifier {
 			self.state_db.lock().unwrap().boxed_clone(),
 			&self.chain.block_header(&h).expect("h is best block hash: so it's header must exist: qed"),
 			self.build_last_hashes(h.clone()),
+			self.dao_rescue_block_gas_limit(h.clone()),
 			author,
 			gas_floor_target,
 			extra_data,
--- a/ethcore/src/client/config.rs
+++ b/ethcore/src/client/config.rs
@@ -35,4 +35,6 @@ pub struct ClientConfig {
 	pub pruning: journaldb::Algorithm,
 	/// The name of the client instance.
 	pub name: String,
+	/// State db cache-size if not default
+	pub db_cache_size: Option<usize>,
 }
--- a/ethcore/src/client/mod.rs
+++ b/ethcore/src/client/mod.rs
@@ -42,7 +42,7 @@ use header::{BlockNumber, Header};
 use transaction::{LocalizedTransaction, SignedTransaction};
 use log_entry::LocalizedLogEntry;
 use filter::Filter;
-use views::BlockView;
+use views::{HeaderView, BlockView};
 use error::{ImportResult, ExecutionError};
 use receipt::LocalizedReceipt;
 use trace::LocalizedTrace;
@@ -193,6 +193,9 @@ pub trait BlockChainClient : Sync + Send {
 	/// import transactions from network/other 3rd party
 	fn import_transactions(&self, transactions: Vec<SignedTransaction>) -> Vec<Result<TransactionImportResult, EthError>>;

+	/// Queue transactions for importing.
+	fn queue_transactions(&self, transactions: Vec<Bytes>);
+
 	/// list all transactions
 	fn all_transactions(&self) -> Vec<SignedTransaction>;

@@ -221,6 +224,28 @@ pub trait BlockChainClient : Sync + Send {
 			Err(())
 		}
 	}
+
+	/// Get `Some` gas limit of SOFT_FORK_BLOCK, or `None` if chain is not yet that long.
+	fn dao_rescue_block_gas_limit(&self, chain_hash: H256) -> Option<U256> {
+		const SOFT_FORK_BLOCK: u64 = 1775000;
+		// shortcut if the canon chain is already known.
+		if self.chain_info().best_block_number > SOFT_FORK_BLOCK + 1000 {
+			return self.block_header(BlockID::Number(SOFT_FORK_BLOCK)).map(|header| HeaderView::new(&header).gas_limit());
+		}
+		// otherwise check according to `chain_hash`.
+		if let Some(mut header) = self.block_header(BlockID::Hash(chain_hash)) {
+			if HeaderView::new(&header).number() < SOFT_FORK_BLOCK {
+				None
+			} else {
+				while HeaderView::new(&header).number() != SOFT_FORK_BLOCK {
+					header = self.block_header(BlockID::Hash(HeaderView::new(&header).parent_hash())).expect("chain is complete; parent of chain entry must be in chain; qed");
+				}
+				Some(HeaderView::new(&header).gas_limit())
+			}
+		} else {
+			None
+		}
+	}	
 }

 /// Extended client interface used for mining
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@@ -188,7 +188,7 @@ impl TestBlockChainClient {
 					txs.append(&signed_tx);
 					txs.out()
 				},
-				_ => rlp::NULL_RLP.to_vec()
+				_ => rlp::EMPTY_LIST_RLP.to_vec()
 			};

 			let mut rlp = RlpStream::new_list(3);
@@ -491,7 +491,13 @@ impl BlockChainClient for TestBlockChainClient {
 			balance: balances[a],
 		};

-		self.miner.import_transactions(transactions, &fetch_account)
+		self.miner.import_transactions(self, transactions, &fetch_account)
+	}
+
+	fn queue_transactions(&self, transactions: Vec<Bytes>) {
+		// import right here
+		let tx = transactions.into_iter().filter_map(|bytes| UntrustedRlp::new(&bytes).as_val().ok()).collect();
+		self.import_transactions(tx);
 	}

 	fn all_transactions(&self) -> Vec<SignedTransaction> {
--- a/ethcore/src/env_info.rs
+++ b/ethcore/src/env_info.rs
@@ -39,6 +39,9 @@ pub struct EnvInfo {
 	pub last_hashes: LastHashes,
 	/// The gas used.
 	pub gas_used: U256,
+
+	/// Block gas limit at DAO rescue block SOFT_FORK_BLOCK or None if not yet there.
+	pub dao_rescue_block_gas_limit: Option<U256>,
 }

 impl Default for EnvInfo {
@@ -51,6 +54,7 @@ impl Default for EnvInfo {
 			gas_limit: 0.into(),
 			last_hashes: vec![],
 			gas_used: 0.into(),
+			dao_rescue_block_gas_limit: None,
 		}
 	}
 }
@@ -66,6 +70,7 @@ impl From<ethjson::vm::Env> for EnvInfo {
 			timestamp: e.timestamp.into(),
 			last_hashes: (1..cmp::min(number + 1, 257)).map(|i| format!("{}", number - i).as_bytes().sha3()).collect(),
 			gas_used: U256::zero(),
+			dao_rescue_block_gas_limit: None,
 		}
 	}
 }
--- a/ethcore/src/error.rs
+++ b/ethcore/src/error.rs
@@ -228,7 +228,7 @@ pub enum Error {
 	/// The value of the nonce or mishash is invalid.
 	PowInvalid,
 	/// Error concerning TrieDBs
-	TrieError(TrieError),
+	Trie(TrieError),
 }

 impl fmt::Display for Error {
@@ -244,7 +244,7 @@ impl fmt::Display for Error {
 				f.write_fmt(format_args!("Unknown engine name ({})", name)),
 			Error::PowHashInvalid => f.write_str("Invalid or out of date PoW hash."),
 			Error::PowInvalid => f.write_str("Invalid nonce or mishash"),
-			Error::TrieError(ref err) => f.write_fmt(format_args!("{}", err)),
+			Error::Trie(ref err) => f.write_fmt(format_args!("{}", err)),
 		}
 	}
 }
@@ -308,7 +308,7 @@ impl From<IoError> for Error {

 impl From<TrieError> for Error {
 	fn from(err: TrieError) -> Error {
-		Error::TrieError(err)
+		Error::Trie(err)
 	}
 }

--- a/ethcore/src/ethereum/ethash.rs
+++ b/ethcore/src/ethereum/ethash.rs
@@ -41,6 +41,8 @@ pub struct EthashParams {
 	pub registrar: Address,
 	/// Homestead transition block number.
 	pub frontier_compatibility_mode_limit: u64,
+	/// Enable the soft-fork logic.
+	pub dao_rescue_soft_fork: bool,
 }

 impl From<ethjson::spec::EthashParams> for EthashParams {
@@ -53,6 +55,7 @@ impl From<ethjson::spec::EthashParams> for EthashParams {
 			block_reward: p.block_reward.into(),
 			registrar: p.registrar.into(),
 			frontier_compatibility_mode_limit: p.frontier_compatibility_mode_limit.into(),
+			dao_rescue_soft_fork: p.dao_rescue_soft_fork.into(),
 		}
 	}
 }
@@ -102,8 +105,9 @@ impl Engine for Ethash {
 			Schedule::new_frontier()
 		} else {
 			let mut s = Schedule::new_homestead();
-			// TODO: make dependent on gaslimit > 4000000 of block 1760000.	
-			s.reject_dao_transactions = env_info.number >= 1760000;
+			if self.ethash_params.dao_rescue_soft_fork {
+				s.reject_dao_transactions = env_info.dao_rescue_block_gas_limit.map_or(false, |x| x <= 4_000_000.into());
+			}
 			s
 		}
 	}
@@ -319,7 +323,7 @@ mod tests {
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let last_hashes = vec![genesis_header.hash()];
 		let vm_factory = Default::default();
-		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, Address::zero(), 3141562.into(), vec![]).unwrap();
+		let b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, None, Address::zero(), 3141562.into(), vec![]).unwrap();
 		let b = b.close();
 		assert_eq!(b.state().balance(&Address::zero()), U256::from_str("4563918244f40000").unwrap());
 	}
@@ -334,7 +338,7 @@ mod tests {
 		spec.ensure_db_good(db.as_hashdb_mut());
 		let last_hashes = vec![genesis_header.hash()];
 		let vm_factory = Default::default();
-		let mut b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, Address::zero(), 3141562.into(), vec![]).unwrap();
+		let mut b = OpenBlock::new(engine.deref(), &vm_factory, false, db, &genesis_header, last_hashes, None, Address::zero(), 3141562.into(), vec![]).unwrap();
 		let mut uncle = Header::new();
 		let uncle_author = address_from_hex("ef2d6d194084c2de36e0dabfce45d046b37d1106");
 		uncle.author = uncle_author.clone();
@@ -362,7 +366,8 @@ mod tests {
 			difficulty: 0.into(),
 			last_hashes: vec![],
 			gas_used: 0.into(),
-			gas_limit: 0.into()
+			gas_limit: 0.into(),
+			dao_rescue_block_gas_limit: None,
 		});

 		assert!(schedule.stack_limit > 0);
@@ -374,7 +379,8 @@ mod tests {
 			difficulty: 0.into(),
 			last_hashes: vec![],
 			gas_used: 0.into(),
-			gas_limit: 0.into()
+			gas_limit: 0.into(),
+			dao_rescue_block_gas_limit: None,
 		});

 		assert!(!schedule.have_delegate_call);
--- a/ethcore/src/ethereum/mod.rs
+++ b/ethcore/src/ethereum/mod.rs
@@ -33,7 +33,12 @@ use super::spec::*;
 pub fn new_olympic() -> Spec { Spec::load(include_bytes!("../../res/ethereum/olympic.json")) }

 /// Create a new Frontier mainnet chain spec.
-pub fn new_frontier() -> Spec { Spec::load(include_bytes!("../../res/ethereum/frontier.json")) }
+pub fn new_frontier(dao_rescue: bool) -> Spec {
+	Spec::load(match dao_rescue {
+		true => include_bytes!("../../res/ethereum/frontier_dao_rescue.json"),
+		false => include_bytes!("../../res/ethereum/frontier.json"),
+	})
+}

 /// Create a new Frontier chain spec as though it never changes to Homestead.
 pub fn new_frontier_test() -> Spec { Spec::load(include_bytes!("../../res/ethereum/frontier_test.json")) }
@@ -84,7 +89,7 @@ mod tests {

 	#[test]
 	fn frontier() {
-		let frontier = new_frontier();
+		let frontier = new_frontier(true);

 		assert_eq!(frontier.state_root(), H256::from_str("d7f8974fb5ac78d9ac099b9ad5018bedc2ce0a72dad1827a1709da30580f0544").unwrap());
 		let genesis = frontier.genesis_block();
--- a/ethcore/src/evm/jit.rs
+++ b/ethcore/src/evm/jit.rs
@@ -16,9 +16,8 @@

 //! Just in time compiler execution environment.
 use common::*;
-use trace::VMTracer;
 use evmjit;
-use evm::{self, Error, GasLeft};
+use evm::{self, GasLeft};

 /// Should be used to convert jit types to ethcore
 trait FromJit<T>: Sized {
@@ -303,7 +302,7 @@ impl<'a> evmjit::Ext for ExtAdapter<'a> {

 #[derive(Default)]
 pub struct JitEvm {
-	ctxt: Option<evmjit::ContextHandle>,
+	context: Option<evmjit::ContextHandle>,
 }

 impl evm::Evm for JitEvm {
@@ -347,7 +346,7 @@ impl evm::Evm for JitEvm {
 		data.timestamp = ext.env_info().timestamp as i64;

 		self.context = Some(unsafe { evmjit::ContextHandle::new(data, schedule, &mut ext_handle) });
-		let context = self.context.as_ref_mut().unwrap();
+		let mut context = self.context.as_mut().unwrap();
 		let res = context.exec();

 		match res {
--- a/ethcore/src/externalities.rs
+++ b/ethcore/src/externalities.rs
@@ -318,7 +318,8 @@ mod tests {
 			difficulty: 0.into(),
 			last_hashes: vec![],
 			gas_used: 0.into(),
-			gas_limit: 0.into()
+			gas_limit: 0.into(),
+			dao_rescue_block_gas_limit: None,
 		}
 	}

--- a/ethcore/src/miner/miner.rs
+++ b/ethcore/src/miner/miner.rs
@@ -89,34 +89,37 @@ impl Miner {
 	#[cfg_attr(feature="dev", allow(cyclomatic_complexity))]
 	fn prepare_sealing(&self, chain: &MiningBlockChainClient) {
 		trace!(target: "miner", "prepare_sealing: entering");
-		let transactions = self.transaction_queue.lock().unwrap().top_transactions();
-		let mut sealing_work = self.sealing_work.lock().unwrap();
-		let best_hash = chain.best_block_header().sha3();

+		let (transactions, mut open_block) = {
+			let transactions = {self.transaction_queue.lock().unwrap().top_transactions()};
+			let mut sealing_work = self.sealing_work.lock().unwrap();
+			let best_hash = chain.best_block_header().sha3();
 /*
-		// check to see if last ClosedBlock in would_seals is actually same parent block.
-		// if so
-		//   duplicate, re-open and push any new transactions.
-		//   if at least one was pushed successfully, close and enqueue new ClosedBlock;
-		//   otherwise, leave everything alone.
-		// otherwise, author a fresh block.
+			// check to see if last ClosedBlock in would_seals is actually same parent block.
+			// if so
+			//   duplicate, re-open and push any new transactions.
+			//   if at least one was pushed successfully, close and enqueue new ClosedBlock;
+			//   otherwise, leave everything alone.
+			// otherwise, author a fresh block.
 */
-		let mut open_block = match sealing_work.pop_if(|b| b.block().fields().header.parent_hash() == &best_hash) {
-			Some(old_block) => {
-				trace!(target: "miner", "Already have previous work; updating and returning");
-				// add transactions to old_block
-				let e = self.engine();
-				old_block.reopen(e, chain.vm_factory())
-			}
-			None => {
-				// block not found - create it.
-				trace!(target: "miner", "No existing work - making new block");
-				chain.prepare_open_block(
-					self.author(),
-					self.gas_floor_target(),
-					self.extra_data()
-				)
-			}
+			let open_block = match sealing_work.pop_if(|b| b.block().fields().header.parent_hash() == &best_hash) {
+				Some(old_block) => {
+					trace!(target: "miner", "Already have previous work; updating and returning");
+					// add transactions to old_block
+					let e = self.engine();
+					old_block.reopen(e, chain.vm_factory())
+				}
+				None => {
+					// block not found - create it.
+					trace!(target: "miner", "No existing work - making new block");
+					chain.prepare_open_block(
+						self.author(),
+						self.gas_floor_target(),
+						self.extra_data()
+					)
+				}
+			};
+			(transactions, open_block)
 		};

 		let mut invalid_transactions = HashSet::new();
@@ -146,14 +149,16 @@ impl Miner {

 		let block = open_block.close();

-		let mut queue = self.transaction_queue.lock().unwrap();
 		let fetch_account = |a: &Address| AccountDetails {
 			nonce: chain.latest_nonce(a),
 			balance: chain.latest_balance(a),
 		};

-		for hash in invalid_transactions.into_iter() {
-			queue.remove_invalid(&hash, &fetch_account);
+		{
+			let mut queue = self.transaction_queue.lock().unwrap();
+			for hash in invalid_transactions.into_iter() {
+				queue.remove_invalid(&hash, &fetch_account);
+			}
 		}

 		if !block.transactions().is_empty() {
@@ -179,6 +184,8 @@ impl Miner {
 				trace!(target: "miner", "prepare_sealing: unable to generate seal internally");
 			}
 		}
+
+		let mut sealing_work = self.sealing_work.lock().unwrap();
 		if sealing_work.peek_last_ref().map_or(true, |pb| pb.block().fields().header.hash() != block.block().fields().header.hash()) {
 			trace!(target: "miner", "Pushing a new, refreshed or borrowed pending {}...", block.block().fields().header.hash());
 			sealing_work.push(block);
@@ -250,6 +257,7 @@ impl MinerService for Miner {
 					last_hashes: last_hashes,
 					gas_used: U256::zero(),
 					gas_limit: U256::max_value(),
+					dao_rescue_block_gas_limit: chain.dao_rescue_block_gas_limit(header.parent_hash().clone()),
 				};
 				// that's just a copy of the state.
 				let mut state = block.state().clone();
@@ -359,13 +367,19 @@ impl MinerService for Miner {
 		*self.gas_floor_target.read().unwrap()
 	}

-	fn import_transactions<T>(&self, transactions: Vec<SignedTransaction>, fetch_account: T) ->
+	fn import_transactions<T>(&self, chain: &MiningBlockChainClient, transactions: Vec<SignedTransaction>, fetch_account: T) ->
 		Vec<Result<TransactionImportResult, Error>>
 		where T: Fn(&Address) -> AccountDetails {
-		let mut transaction_queue = self.transaction_queue.lock().unwrap();
-		transactions.into_iter()
-			.map(|tx| transaction_queue.add(tx, &fetch_account, TransactionOrigin::External))
-			.collect()
+		let results: Vec<Result<TransactionImportResult, Error>> = {
+			let mut transaction_queue = self.transaction_queue.lock().unwrap();
+			transactions.into_iter()
+				.map(|tx| transaction_queue.add(tx, &fetch_account, TransactionOrigin::External))
+				.collect()
+		};
+		if !results.is_empty() {
+			self.update_sealing(chain);
+		}
+		results
 	}

 	fn import_own_transaction<T>(
@@ -547,7 +561,7 @@ impl MinerService for Miner {
 				for tx in &txs {
 					let _sender = tx.sender();
 				}
-				let _ = self.import_transactions(txs, |a| AccountDetails {
+				let _ = self.import_transactions(chain, txs, |a| AccountDetails {
 					nonce: chain.latest_nonce(a),
 					balance: chain.latest_balance(a),
 				});
@@ -586,6 +600,7 @@ mod tests {
 	use util::*;
 	use client::{TestBlockChainClient, EachBlockWith};
 	use block::*;
+	use spec::Spec;

 	// TODO [ToDr] To uncomment` when TestBlockChainClient can actually return a ClosedBlock.
 	#[ignore]
--- a/ethcore/src/miner/mod.rs
+++ b/ethcore/src/miner/mod.rs
@@ -95,7 +95,7 @@ pub trait MinerService : Send + Sync {
 	fn set_transactions_limit(&self, limit: usize);

 	/// Imports transactions to transaction queue.
-	fn import_transactions<T>(&self, transactions: Vec<SignedTransaction>, fetch_account: T) ->
+	fn import_transactions<T>(&self, chain: &MiningBlockChainClient, transactions: Vec<SignedTransaction>, fetch_account: T) ->
 		Vec<Result<TransactionImportResult, Error>>
 		where T: Fn(&Address) -> AccountDetails, Self: Sized;

--- a/ethcore/src/miner/transaction_queue.rs
+++ b/ethcore/src/miner/transaction_queue.rs
@@ -167,16 +167,17 @@ impl PartialOrd for TransactionOrder {

 impl Ord for TransactionOrder {
 	fn cmp(&self, b: &TransactionOrder) -> Ordering {
-		// Local transactions should always have priority
-		if self.origin != b.origin {
-			return self.origin.cmp(&b.origin);
-		}
-
 		// First check nonce_height
 		if self.nonce_height != b.nonce_height {
 			return self.nonce_height.cmp(&b.nonce_height);
 		}

+		// Local transactions should always have priority
+		// NOTE nonce has to be checked first, cause otherwise the order might be wrong.
+		if self.origin != b.origin {
+			return self.origin.cmp(&b.origin);
+		}
+
 		// Then compare gas_prices
 		let a_gas = self.gas_price;
 		let b_gas = b.gas_price;
@@ -235,22 +236,22 @@ impl TransactionSet {
 		self.by_priority.insert(order.clone());
 		let r = self.by_address.insert(sender, nonce, order);
 		// If transaction was replaced remove it from priority queue
-		if let Some(ref order) = r {
-			self.by_priority.remove(order);
+		if let Some(ref old_order) = r {
+			self.by_priority.remove(old_order);
 		}
+		assert_eq!(self.by_priority.len(), self.by_address.len());
 		r
 	}

 	/// Remove low priority transactions if there is more then specified by given `limit`.
 	///
 	/// It drops transactions from this set but also removes associated `VerifiedTransaction`.
-	/// Returns addresses and highes nonces of transactions removed because of limit.
+	/// Returns addresses and lowest nonces of transactions removed because of limit.
 	fn enforce_limit(&mut self, by_hash: &mut HashMap<H256, VerifiedTransaction>) -> Option<HashMap<Address, U256>> {
 		let len = self.by_priority.len();
 		if len <= self.limit {
 			return None;
 		}
-
 		let to_drop : Vec<(Address, U256)> = {
 			self.by_priority
 				.iter()
@@ -269,8 +270,8 @@ impl TransactionSet {
 				by_hash.remove(&order.hash)
 					.expect("Hash found in `by_priorty` matches the one dropped; so it is included in `by_hash`");

-				let max = removed.get(&sender).map_or(nonce, |val| cmp::max(*val, nonce));
-				removed.insert(sender, max);
+				let min = removed.get(&sender).map_or(nonce, |val| cmp::min(*val, nonce));
+				removed.insert(sender, min);
 				removed
 			}))
 	}
@@ -279,8 +280,10 @@ impl TransactionSet {
 	fn drop(&mut self, sender: &Address, nonce: &U256) -> Option<TransactionOrder> {
 		if let Some(tx_order) = self.by_address.remove(sender, nonce) {
 			self.by_priority.remove(&tx_order);
+			assert_eq!(self.by_priority.len(), self.by_address.len());
 			return Some(tx_order);
 		}
+		assert_eq!(self.by_priority.len(), self.by_address.len());
 		None
 	}

@@ -468,7 +471,9 @@ impl TransactionQueue {
 			}));
 		}

-		self.import_tx(vtx, client_account.nonce).map_err(Error::Transaction)
+		let r = self.import_tx(vtx, client_account.nonce).map_err(Error::Transaction);
+		assert_eq!(self.future.by_priority.len() + self.current.by_priority.len(), self.by_hash.len());
+		r
 	}

 	/// Removes all transactions from particular sender up to (excluding) given client (state) nonce.
@@ -484,6 +489,7 @@ impl TransactionQueue {
 		// And now lets check if there is some batch of transactions in future
 		// that should be placed in current. It should also update last_nonces.
 		self.move_matching_future_to_current(sender, client_nonce, client_nonce);
+		assert_eq!(self.future.by_priority.len() + self.current.by_priority.len(), self.by_hash.len());
 	}

 	/// Removes invalid transaction identified by hash from queue.
@@ -493,6 +499,8 @@ impl TransactionQueue {
 	/// If gap is introduced marks subsequent transactions as future
 	pub fn remove_invalid<T>(&mut self, transaction_hash: &H256, fetch_account: &T)
 		where T: Fn(&Address) -> AccountDetails {
+
+		assert_eq!(self.future.by_priority.len() + self.current.by_priority.len(), self.by_hash.len());
 		let transaction = self.by_hash.remove(transaction_hash);
 		if transaction.is_none() {
 			// We don't know this transaction
@@ -511,22 +519,17 @@ impl TransactionQueue {
 			// And now lets check if there is some chain of transactions in future
 			// that should be placed in current
 			self.move_matching_future_to_current(sender, current_nonce, current_nonce);
+			assert_eq!(self.future.by_priority.len() + self.current.by_priority.len(), self.by_hash.len());
 			return;
 		}

 		// Remove from current
 		let order = self.current.drop(&sender, &nonce);
 		if order.is_some() {
-			// We will either move transaction to future or remove it completely
-			// so there will be no transactions from this sender in current
-			self.last_nonces.remove(&sender);
-			// First update height of transactions in future to avoid collisions
-			self.update_future(&sender, current_nonce);
-			// This should move all current transactions to future and remove old transactions
-			self.move_all_to_future(&sender, current_nonce);
-			// And now lets check if there is some chain of transactions in future
-			// that should be placed in current. It should also update last_nonces.
-			self.move_matching_future_to_current(sender, current_nonce, current_nonce);
+			// This will keep consistency in queue
+			// Moves all to future and then promotes a batch from current:
+			self.remove_all(sender, current_nonce);
+			assert_eq!(self.future.by_priority.len() + self.current.by_priority.len(), self.by_hash.len());
 			return;
 		}
 	}
@@ -545,7 +548,7 @@ impl TransactionQueue {
 			} else {
 				trace!(target: "miner", "Removing old transaction: {:?} (nonce: {} < {})", order.hash, k, current_nonce);
 				// Remove the transaction completely
-				self.by_hash.remove(&order.hash);
+				self.by_hash.remove(&order.hash).expect("All transactions in `future` are also in `by_hash`");
 			}
 		}
 	}
@@ -565,7 +568,7 @@ impl TransactionQueue {
 				self.future.insert(*sender, k, order.update_height(k, current_nonce));
 			} else {
 				trace!(target: "miner", "Removing old transaction: {:?} (nonce: {} < {})", order.hash, k, current_nonce);
-				self.by_hash.remove(&order.hash);
+				self.by_hash.remove(&order.hash).expect("All transactions in `future` are also in `by_hash`");
 			}
 		}
 		self.future.enforce_limit(&mut self.by_hash);
@@ -664,21 +667,27 @@ impl TransactionQueue {
 			.cloned()
 			.map_or(state_nonce, |n| n + U256::one());

-		// Check height
-		if nonce > next_nonce {
-			// We have a gap - put to future
-			try!(check_too_cheap(Self::replace_transaction(tx, next_nonce, &mut self.future, &mut self.by_hash)));
-			try!(check_if_removed(&address, &nonce, self.future.enforce_limit(&mut self.by_hash)));
-			return Ok(TransactionImportResult::Future);
-		} else if nonce < state_nonce {
+		// The transaction might be old, let's check that.
+		// This has to be the first test, otherwise calculating
+		// nonce height would result in overflow.
+		if nonce < state_nonce {
 			// Droping transaction
 			trace!(target: "miner", "Dropping old transaction: {:?} (nonce: {} < {})", tx.hash(), nonce, next_nonce);
 			return Err(TransactionError::Old);
+		} else if nonce > next_nonce {
+			// We have a gap - put to future.
+			// Update nonces of transactions in future (remove old transactions)
+			self.update_future(&address, state_nonce);
+			// Insert transaction (or replace old one with lower gas price)
+			try!(check_too_cheap(Self::replace_transaction(tx, state_nonce, &mut self.future, &mut self.by_hash)));
+			// Return an error if this transaction is not imported because of limit.
+			try!(check_if_removed(&address, &nonce, self.future.enforce_limit(&mut self.by_hash)));
+			return Ok(TransactionImportResult::Future);
 		}
-
 		try!(check_too_cheap(Self::replace_transaction(tx, state_nonce, &mut self.current, &mut self.by_hash)));
 		// Keep track of highest nonce stored in current
-		self.last_nonces.insert(address, nonce);
+		let new_max = self.last_nonces.get(&address).map_or(nonce, |n| cmp::max(nonce, *n));
+		self.last_nonces.insert(address, new_max);
 		// Update nonces of transactions in future
 		self.update_future(&address, state_nonce);
 		// Maybe there are some more items waiting in future?
@@ -687,15 +696,16 @@ impl TransactionQueue {
 		// same (sender, nonce), but above function would not move it.
 		if let Some(order) = self.future.drop(&address, &nonce) {
 			// Let's insert that transaction to current (if it has higher gas_price)
-			let future_tx = self.by_hash.remove(&order.hash).unwrap();
-			try!(check_too_cheap(Self::replace_transaction(future_tx, state_nonce, &mut self.current, &mut self.by_hash)));
+			let future_tx = self.by_hash.remove(&order.hash).expect("All transactions in `future` are always in `by_hash`.");
+			// if transaction in `current` (then one we are importing) is replaced it means that it has to low gas_price
+			try!(check_too_cheap(!Self::replace_transaction(future_tx, state_nonce, &mut self.current, &mut self.by_hash)));
 		}

 		// Also enforce the limit
 		let removed = self.current.enforce_limit(&mut self.by_hash);
 		// If some transaction were removed because of limit we need to update last_nonces also.
 		self.update_last_nonces(&removed);
-		// Trigger error if we were removed.
+		// Trigger error if the transaction we are importing was removed.
 		try!(check_if_removed(&address, &nonce, removed));

 		trace!(target: "miner", "status: {:?}", self.status());
@@ -703,9 +713,9 @@ impl TransactionQueue {
 	}

 	/// Updates
-	fn update_last_nonces(&mut self, removed_max_nonces: &Option<HashMap<Address, U256>>) {
-		if let Some(ref max_nonces) = *removed_max_nonces {
-			for (sender, nonce) in max_nonces.iter() {
+	fn update_last_nonces(&mut self, removed_min_nonces: &Option<HashMap<Address, U256>>) {
+		if let Some(ref min_nonces) = *removed_min_nonces {
+			for (sender, nonce) in min_nonces.iter() {
 				if *nonce == U256::zero() {
 					self.last_nonces.remove(sender);
 				} else {
@@ -728,7 +738,9 @@ impl TransactionQueue {
 		let address = tx.sender();
 		let nonce = tx.nonce();

-		by_hash.insert(hash, tx);
+		let old_hash = by_hash.insert(hash, tx);
+		assert!(old_hash.is_none(), "Each hash has to be inserted exactly once.");
+

 		if let Some(old) = set.insert(address, nonce, order.clone()) {
 			// There was already transaction in queue. Let's check which one should stay
@@ -738,11 +750,11 @@ impl TransactionQueue {
 				// Put back old transaction since it has greater priority (higher gas_price)
 				set.insert(address, nonce, old);
 				// and remove new one
-				by_hash.remove(&hash);
+				by_hash.remove(&hash).expect("The hash has been just inserted and no other line is altering `by_hash`.");
 				false
 			} else {
 				// Make sure we remove old transaction entirely
-				by_hash.remove(&old.hash);
+				by_hash.remove(&old.hash).expect("The hash is coming from `future` so it has to be in `by_hash`.");
 				true
 			}
 		} else {
@@ -762,7 +774,7 @@ fn check_too_cheap(is_in: bool) -> Result<(), TransactionError> {
 fn check_if_removed(sender: &Address, nonce: &U256, dropped: Option<HashMap<Address, U256>>) -> Result<(), TransactionError> {
 	match dropped {
 		Some(ref dropped) => match dropped.get(sender) {
-			Some(max) if nonce <= max => {
+			Some(min) if nonce >= min => {
 				Err(TransactionError::LimitReached)
 			},
 			_ => Ok(()),
@@ -939,7 +951,7 @@ mod test {
 		let res = txq.add(tx2.clone(), &default_nonce, TransactionOrigin::External);

 		// and then there should be only one transaction in current (the one with higher gas_price)
-		assert_eq!(unwrap_tx_err(res), TransactionError::TooCheapToReplace);
+		assert_eq!(res.unwrap(), TransactionImportResult::Current);
 		assert_eq!(txq.status().pending, 1);
 		assert_eq!(txq.status().future, 0);
 		assert_eq!(txq.current.by_priority.len(), 1);
@@ -1087,7 +1099,28 @@ mod test {
 	}

 	#[test]
-	fn should_prioritize_local_transactions() {
+	fn should_prioritize_local_transactions_within_same_nonce_height() {
+		// given
+		let mut txq = TransactionQueue::new();
+		let tx = new_tx();
+		// the second one has same nonce but higher `gas_price`
+		let (_, tx2) = new_similar_txs();
+
+		// when
+		// first insert the one with higher gas price
+		txq.add(tx2.clone(), &default_nonce, TransactionOrigin::External).unwrap();
+		// then the one with lower gas price, but local
+		txq.add(tx.clone(), &default_nonce, TransactionOrigin::Local).unwrap();
+
+		// then
+		let top = txq.top_transactions();
+		assert_eq!(top[0], tx); // local should be first
+		assert_eq!(top[1], tx2);
+		assert_eq!(top.len(), 2);
+	}
+
+	#[test]
+	fn should_not_prioritize_local_transactions_with_different_nonce_height() {
 		// given
 		let mut txq = TransactionQueue::new();
 		let (tx, tx2) = new_txs(U256::from(1));
@@ -1098,8 +1131,8 @@ mod test {

 		// then
 		let top = txq.top_transactions();
-		assert_eq!(top[0], tx2);
-		assert_eq!(top[1], tx);
+		assert_eq!(top[0], tx);
+		assert_eq!(top[1], tx2);
 		assert_eq!(top.len(), 2);
 	}

@@ -1555,4 +1588,54 @@ mod test {
 		assert_eq!(txq.has_local_pending_transactions(), true);
 	}

+	#[test]
+	fn should_keep_right_order_in_future() {
+		// given
+		let mut txq = TransactionQueue::with_limit(1);
+		let (tx1, tx2) = new_txs(U256::from(1));
+		let prev_nonce = |a: &Address| AccountDetails { nonce: default_nonce(a).nonce - U256::one(), balance:
+			default_nonce(a).balance };
+
+		// when
+		assert_eq!(txq.add(tx2, &prev_nonce, TransactionOrigin::External).unwrap(), TransactionImportResult::Future);
+		assert_eq!(txq.add(tx1.clone(), &prev_nonce, TransactionOrigin::External).unwrap(), TransactionImportResult::Future);
+
+		// then
+		assert_eq!(txq.future.by_priority.len(), 1);
+		assert_eq!(txq.future.by_priority.iter().next().unwrap().hash, tx1.hash());
+	}
+
+	#[test]
+	fn should_return_correct_last_nonce() {
+		// given
+		let mut txq = TransactionQueue::new();
+		let (tx1, tx2, tx2_2, tx3) = {
+			let keypair = KeyPair::create().unwrap();
+			let secret = &keypair.secret();
+			let nonce = U256::from(123);
+			let tx = new_unsigned_tx(nonce);
+			let tx2 = new_unsigned_tx(nonce + 1.into());
+			let mut tx2_2 = new_unsigned_tx(nonce + 1.into());
+			tx2_2.gas_price = U256::from(5);
+			let tx3 = new_unsigned_tx(nonce + 2.into());
+
+
+			(tx.sign(secret), tx2.sign(secret), tx2_2.sign(secret), tx3.sign(secret))
+		};
+		let sender = tx1.sender().unwrap();
+		txq.add(tx1, &default_nonce, TransactionOrigin::Local).unwrap();
+		txq.add(tx2, &default_nonce, TransactionOrigin::Local).unwrap();
+		txq.add(tx3, &default_nonce, TransactionOrigin::Local).unwrap();
+		assert_eq!(txq.future.by_priority.len(), 0);
+		assert_eq!(txq.current.by_priority.len(), 3);
+
+		// when
+		let res = txq.add(tx2_2, &default_nonce, TransactionOrigin::Local);
+
+		// then
+		assert_eq!(txq.last_nonce(&sender).unwrap(), 125.into());
+		assert_eq!(res.unwrap(), TransactionImportResult::Current);
+		assert_eq!(txq.current.by_priority.len(), 3);
+	}
+
 }
--- a/ethcore/src/service.rs
+++ b/ethcore/src/service.rs
@@ -41,6 +41,8 @@ pub enum SyncMessage {
 	NewChainHead,
 	/// A block is ready
 	BlockVerified,
+	/// New transaction RLPs are ready to be imported
+	NewTransactions(Vec<Bytes>),
 	/// Start network command.
 	StartNetwork,
 	/// Stop network command.
@@ -136,6 +138,9 @@ impl IoHandler<NetSyncMessage> for ClientIoHandler {
 				SyncMessage::BlockVerified => {
 					self.client.import_verified_blocks(&io.channel());
 				},
+				SyncMessage::NewTransactions(ref transactions) => {
+					self.client.import_queued_transactions(&transactions);
+				},
 				_ => {}, // ignore other messages
 			}
 		}
@@ -154,9 +159,15 @@ mod tests {

 	#[test]
 	fn it_can_be_started() {
-		let spec = get_test_spec();
 		let temp_path = RandomTempPath::new();
-		let service = ClientService::start(ClientConfig::default(), spec, NetworkConfiguration::new_local(), &temp_path.as_path(), Arc::new(Miner::with_spec(spec)), false);
+		let service = ClientService::start(
+			ClientConfig::default(),
+			get_test_spec(),
+			NetworkConfiguration::new_local(),
+			&temp_path.as_path(),
+			Arc::new(Miner::with_spec(get_test_spec())),
+			false
+		);
 		assert!(service.is_ok());
 	}
 }
--- a/ethcore/src/state.rs
+++ b/ethcore/src/state.rs
@@ -222,19 +222,25 @@ impl State {
 		let options = TransactOptions { tracing: tracing, vm_tracing: false, check_nonce: true };
 		let e = try!(Executive::new(self, env_info, engine, vm_factory).transact(t, options));

-		let broken_dao = H256::from("7278d050619a624f84f51987149ddb439cdaadfba5966f7cfaea7ad44340a4ba");
+		let broken_dao = H256::from("6a5d24750f78441e56fec050dc52fe8e911976485b7472faac7464a176a67caa");

 		// dao attack soft fork
 		if engine.schedule(&env_info).reject_dao_transactions {
-			// collect all the addresses which have changed.
-			let addresses = self.cache.borrow().iter().map(|(addr, _)| addr.clone()).collect::<Vec<_>>();
+			let whitelisted = if let Action::Call(to) = t.action {
+				to == Address::from("Da4a4626d3E16e094De3225A751aAb7128e96526") ||
+				to == Address::from("2ba9D006C1D72E67A70b5526Fc6b4b0C0fd6D334")
+			} else { false };
+			if !whitelisted {
+				// collect all the addresses which have changed.
+				let addresses = self.cache.borrow().iter().map(|(addr, _)| addr.clone()).collect::<Vec<_>>();

-			for a in &addresses {
-				if self.code(a).map_or(false, |c| c.sha3() == broken_dao) {
-					// Figure out if the balance has been reduced.
-					let maybe_original = SecTrieDB::new(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR).get(&a).map(Account::from_rlp);
-					if maybe_original.map_or(false, |original| *original.balance() > self.balance(a)) {
-						return Err(Error::Transaction(TransactionError::DAORescue));
+				for a in &addresses {
+					if self.code(a).map_or(false, |c| c.sha3() == broken_dao) {
+						// Figure out if the balance has been reduced.
+						let maybe_original = SecTrieDB::new(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR).get(&a).map(Account::from_rlp);
+						if maybe_original.map_or(false, |original| *original.balance() > self.balance(a)) {
+							return Err(Error::Transaction(TransactionError::DAORescue));
+						}
 					}
 				}
 			}
--- a/ethcore/src/tests/helpers.rs
+++ b/ethcore/src/tests/helpers.rs
@@ -179,6 +179,7 @@ pub fn generate_dummy_client_with_spec_and_data<F>(get_test_spec: F, block_numbe
 			db,
 			&last_header,
 			last_hashes.clone(),
+			None,
 			author.clone(),
 			3141562.into(),
 			vec![]
@@ -302,7 +303,7 @@ pub fn generate_dummy_empty_blockchain() -> GuardedTempResult<BlockChain> {

 pub fn get_temp_journal_db() -> GuardedTempResult<Box<JournalDB>> {
 	let temp = RandomTempPath::new();
-	let journal_db = journaldb::new(temp.as_str(), journaldb::Algorithm::EarlyMerge);
+	let journal_db = journaldb::new(temp.as_str(), journaldb::Algorithm::EarlyMerge, None);
 	GuardedTempResult {
 		_temp: temp,
 		result: Some(journal_db)
@@ -319,7 +320,7 @@ pub fn get_temp_state() -> GuardedTempResult<State> {
 }

 pub fn get_temp_journal_db_in(path: &Path) -> Box<JournalDB> {
-	journaldb::new(path.to_str().unwrap(), journaldb::Algorithm::EarlyMerge)
+	journaldb::new(path.to_str().unwrap(), journaldb::Algorithm::EarlyMerge, None)
 }

 pub fn get_temp_state_in(path: &Path) -> State {
--- a/ethcore/src/trace/config.rs
+++ b/ethcore/src/trace/config.rs
@@ -48,6 +48,8 @@ pub struct Config {
 	pub enabled: Switch,
 	/// Traces blooms configuration.
 	pub blooms: BloomConfig,
+	/// Database cache-size if not default
+	pub db_cache_size: Option<usize>,
 }

 impl Default for Config {
@@ -57,7 +59,8 @@ impl Default for Config {
 			blooms: BloomConfig {
 				levels: 3,
 				elements_per_index: 16,
-			}
+			},
+			db_cache_size: None,
 		}
 	}
 }
--- a/ethcore/src/trace/db.rs
+++ b/ethcore/src/trace/db.rs
@@ -22,7 +22,7 @@ use std::sync::{RwLock, Arc};
 use std::path::Path;
 use bloomchain::{Number, Config as BloomConfig};
 use bloomchain::group::{BloomGroupDatabase, BloomGroupChain, GroupPosition, BloomGroup};
-use util::{H256, H264, Database, DBTransaction};
+use util::{H256, H264, Database, DatabaseConfig, DBTransaction};
 use header::BlockNumber;
 use trace::{BlockTraces, LocalizedTrace, Config, Switch, Filter, Database as TraceDatabase, ImportRequest,
 DatabaseExtras, Error};
@@ -118,7 +118,12 @@ impl<T> TraceDB<T> where T: DatabaseExtras {
 	pub fn new(config: Config, path: &Path, extras: Arc<T>) -> Result<Self, Error> {
 		let mut tracedb_path = path.to_path_buf();
 		tracedb_path.push("tracedb");
-		let tracesdb = Database::open_default(tracedb_path.to_str().unwrap()).unwrap();
+		let tracesdb = match config.db_cache_size {
+			None => Database::open_default(tracedb_path.to_str().unwrap()).unwrap(),
+			Some(db_cache) => Database::open(
+				&DatabaseConfig::with_cache(db_cache),
+				tracedb_path.to_str().unwrap()).unwrap(),
+		};

 		// check if in previously tracing was enabled
 		let old_tracing = match tracesdb.get(b"enabled").unwrap() {