mixed merge and changes...

2016-10-11 18:37:31 +01:00 · 2016-10-11 18:37:31 +01:00 · e343153f06
commit e343153f06
parent 1f56588b87
58 changed files with 1397 additions and 621 deletions
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@ -3,8 +3,9 @@ stages:
  - test
 variables:
  GIT_DEPTH: "3"
-  SIMPLECOV: "true" 
+  SIMPLECOV: "true"
  RUST_BACKTRACE: "1"
+  RUSTFLAGS: "-D warnings"
 cache:
  key: "$CI_BUILD_NAME/$CI_BUILD_REF_NAME"
  untracked: true
@ -20,7 +21,7 @@ linux-stable:
    - cargo build --release --verbose
    - strip target/release/parity
    - md5sum target/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-linux-gnu/parity --body target/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-linux-gnu/checksum --body checksum
@ -43,7 +44,7 @@ linux-stable-14.04:
    - cargo build --release --verbose
    - strip target/release/parity
    - md5sum target/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-ubuntu_14_04-gnu/parity --body target/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-ubuntu_14_04-gnu/checksum --body checksum
@ -106,7 +107,7 @@ linux-centos:
    - cargo build --release --verbose
    - strip target/release/parity
    - md5sum target/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-centos-gnu/parity --body target/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-unknown-centos-gnu/checksum --body checksum
@ -134,7 +135,7 @@ linux-armv7:
    - cargo build --target armv7-unknown-linux-gnueabihf --release --verbose
    - arm-linux-gnueabihf-strip target/armv7-unknown-linux-gnueabihf/release/parity
    - md5sum target/armv7-unknown-linux-gnueabihf/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/armv7-unknown-linux-gnueabihf/parity --body target/armv7-unknown-linux-gnueabihf/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/armv7-unknown-linux-gnueabihf/checksum --body checksum
@ -163,7 +164,7 @@ linux-arm:
    - cargo build --target arm-unknown-linux-gnueabihf --release --verbose
    - arm-linux-gnueabihf-strip target/arm-unknown-linux-gnueabihf/release/parity
    - md5sum target/arm-unknown-linux-gnueabihf/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/arm-unknown-linux-gnueabihf/parity --body target/arm-unknown-linux-gnueabihf/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/arm-unknown-linux-gnueabihf/checksum --body checksum
@ -191,8 +192,8 @@ linux-armv6:
    - cat .cargo/config
    - cargo build --target arm-unknown-linux-gnueabi --release --verbose
    - arm-linux-gnueabi-strip target/arm-unknown-linux-gnueabi/release/parity
-    - md5sum target/arm-unknown-linux-gnueabi/release/parity >> checksum 
-    - aws configure set aws_access_key_id $s3_key 
+    - md5sum target/arm-unknown-linux-gnueabi/release/parity >> checksum
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/arm-unknown-linux-gnueabi/parity --body target/arm-unknown-linux-gnueabi/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/arm-unknown-linux-gnueabi/checksum --body checksum
@ -221,7 +222,7 @@ linux-aarch64:
    - cargo build --target aarch64-unknown-linux-gnu --release --verbose
    - aarch64-linux-gnu-strip target/aarch64-unknown-linux-gnu/release/parity
    - md5sum target/aarch64-unknown-linux-gnu/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/aarch64-unknown-linux-gnu/parity --body target/aarch64-unknown-linux-gnu/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/aarch64-unknown-linux-gnu/checksum --body checksum
@ -243,7 +244,7 @@ darwin:
  script:
    - cargo build --release --verbose
    - md5sum target/release/parity >> checksum
-    - aws configure set aws_access_key_id $s3_key 
+    - aws configure set aws_access_key_id $s3_key
    - aws configure set aws_secret_access_key $s3_secret
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-apple-darwin/parity --body target/release/parity
    - aws s3api put-object --bucket builds-parity --key $CI_BUILD_REF_NAME/x86_64-apple-darwin/checksum --body checksum
@ -264,7 +265,7 @@ windows:
    - set INCLUDE=C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Include;C:\vs2015\VC\include;C:\Program Files (x86)\Windows Kits\10\Include\10.0.10240.0\ucrt
    - set LIB=C:\vs2015\VC\lib;C:\Program Files (x86)\Windows Kits\10\Lib\10.0.10240.0\ucrt\x64
    - set RUST_BACKTRACE=1
-    - set RUSTFLAGS=-Zorbit=off
+    - set RUSTFLAGS=%RUSTFLAGS% -Zorbit=off
    - rustup default stable-x86_64-pc-windows-msvc
    - cargo build --release --verbose
    - cmd md5sum target\release\parity >> checksum
--- a/.travis.yml
+++ b/.travis.yml
@ -31,6 +31,7 @@ env:
  - RUN_COVERAGE="false"
  - RUN_DOCS="false"
  - TEST_OPTIONS=""
+  - RUSTFLAGS="-D warnings"
  # GH_TOKEN for documentation
  - secure: 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
  - KCOV_CMD="./kcov-master/tmp/usr/local/bin/kcov"
--- a/Cargo.lock
+++ b/Cargo.lock
@ -240,7 +240,7 @@ version = "0.5.4"
 source = "git+https://github.com/ethcore/rust-secp256k1#a9a0b1be1f39560ca86e8fc8e55e205a753ff25c"
 dependencies = [
 "arrayvec 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
@ -308,7 +308,7 @@ dependencies = [

 [[package]]
 name = "ethcore-bigint"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
 "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
@ -399,6 +399,7 @@ dependencies = [
 "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "nanomsg 0.5.1 (git+https://github.com/ethcore/nanomsg.rs.git)",
 "semver 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -538,7 +539,7 @@ dependencies = [
 "elastic-array 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "env_logger 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "eth-secp256k1 0.5.4 (git+https://github.com/ethcore/rust-secp256k1)",
- "ethcore-bigint 0.1.0",
+ "ethcore-bigint 0.1.1",
 "ethcore-bloom-journal 0.1.0",
 "ethcore-devtools 1.4.0",
 "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@ -567,7 +568,7 @@ name = "ethcrypto"
 version = "0.1.0"
 dependencies = [
 "eth-secp256k1 0.5.4 (git+https://github.com/ethcore/rust-secp256k1)",
- "ethcore-bigint 0.1.0",
+ "ethcore-bigint 0.1.1",
 "ethkey 0.2.0",
 "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 "tiny-keccak 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@ -590,7 +591,7 @@ version = "0.2.0"
 dependencies = [
 "docopt 0.6.80 (registry+https://github.com/rust-lang/crates.io-index)",
 "eth-secp256k1 0.5.4 (git+https://github.com/ethcore/rust-secp256k1)",
- "ethcore-bigint 0.1.0",
+ "ethcore-bigint 0.1.1",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
@ -674,8 +675,11 @@ dependencies = [

 [[package]]
 name = "gcc"
-version = "0.3.28"
+version = "0.3.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rayon 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]

 [[package]]
 name = "glob"
@ -936,7 +940,7 @@ name = "miniz-sys"
 version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -1022,7 +1026,7 @@ name = "nanomsg-sys"
 version = "0.5.0"
 source = "git+https://github.com/ethcore/nanomsg.rs.git#c40fe442c9afaea5b38009a3d992ca044dcceb00"
 dependencies = [
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -1394,7 +1398,7 @@ name = "rlp"
 version = "0.1.0"
 dependencies = [
 "elastic-array 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ethcore-bigint 0.1.0",
+ "ethcore-bigint 0.1.1",
 "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1402,7 +1406,7 @@ dependencies = [
 [[package]]
 name = "rocksdb"
 version = "0.4.5"
-source = "git+https://github.com/ethcore/rust-rocksdb#485dd747a2c9a9f910fc8ac696fc9edf5fa22aa3"
+source = "git+https://github.com/ethcore/rust-rocksdb#ffc7c82380fe8569f85ae6743f7f620af2d4a679"
 dependencies = [
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "rocksdb-sys 0.3.0 (git+https://github.com/ethcore/rust-rocksdb)",
@ -1411,9 +1415,9 @@ dependencies = [
 [[package]]
 name = "rocksdb-sys"
 version = "0.3.0"
-source = "git+https://github.com/ethcore/rust-rocksdb#485dd747a2c9a9f910fc8ac696fc9edf5fa22aa3"
+source = "git+https://github.com/ethcore/rust-rocksdb#ffc7c82380fe8569f85ae6743f7f620af2d4a679"
 dependencies = [
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@ -1444,7 +1448,7 @@ name = "rust-crypto"
 version = "0.2.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.15 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1537,7 +1541,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "sha3"
 version = "0.1.0"
 dependencies = [
- "gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@ -1926,7 +1930,7 @@ dependencies = [
 "checksum eth-secp256k1 0.5.4 (git+https://github.com/ethcore/rust-secp256k1)" = "<none>"
 "checksum ethabi 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f7b0c53453517f620847be51943db329276ae52f2e210cfc659e81182864be2f"
 "checksum flate2 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "3eeb481e957304178d2e782f2da1257f1434dfecbae883bafb61ada2a9fea3bb"
-"checksum gcc 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)" = "3da3a2cbaeb01363c8e3704fd9fd0eb2ceb17c6f27abd4c1ef040fb57d20dc79"
+"checksum gcc 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)" = "91ecd03771effb0c968fd6950b37e89476a578aaf1c70297d8e92b6516ec3312"
 "checksum glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "8be18de09a56b60ed0edf84bc9df007e30040691af7acd1c41874faac5895bfb"
 "checksum hamming 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "65043da274378d68241eb9a8f8f8aa54e349136f7b8e12f63e3ef44043cc30e1"
 "checksum heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "abb306abb8d398e053cfb1b3e7b72c2f580be048b85745c52652954f8ad1439c"
--- a/appveyor.yml
+++ b/appveyor.yml
@ -6,7 +6,7 @@ environment:
  certpass:
    secure: 0BgXJqxq9Ei34/hZ7121FQ==
  keyfile: C:\users\appveyor\Certificates.p12
-  RUSTFLAGS: -Zorbit=off
+  RUSTFLAGS: -Zorbit=off -D warnings

 branches:
  only:
--- a/dapps/src/api/api.rs
+++ b/dapps/src/api/api.rs
@ -92,11 +92,14 @@ impl server::Handler<net::HttpStream> for RestApiRouter {
 		}

 		let url = url.expect("Check for None early-exists above; qed");
-		let path = self.path.take().expect("on_request called only once, and path is always defined in new; qed");
+		let mut path = self.path.take().expect("on_request called only once, and path is always defined in new; qed");
 		let control = self.control.take().expect("on_request called only once, and control is always defined in new; qed");

 		let endpoint = url.path.get(1).map(|v| v.as_str());
 		let hash = url.path.get(2).map(|v| v.as_str());
+		// at this point path.app_id contains 'api', adjust it to the hash properly, otherwise
+		// we will try and retrieve 'api' as the hash when doing the /api/content route
+		if let Some(hash) = hash.clone() { path.app_id = hash.to_owned() }

 		let handler = endpoint.and_then(|v| match v {
 			"apps" => Some(as_json(&self.api.list_apps())),
--- a/dapps/src/apps/fetcher.rs
+++ b/dapps/src/apps/fetcher.rs
@ -122,7 +122,7 @@ impl<R: URLHint> ContentFetcher<R> {
 				},
 				// We need to start fetching app
 				None => {
-					trace!(target: "dapps", "Content unavailable. Fetching...");
+					trace!(target: "dapps", "Content unavailable. Fetching... {:?}", content_id);
 					let content_hex = content_id.from_hex().expect("to_handler is called only when `contains` returns true.");
 					let content = self.resolver.resolve(content_hex);

@ -415,4 +415,3 @@ mod tests {
 		assert_eq!(fetcher.contains("test3"), false);
 	}
 }
-
--- a/ethcore/build.rs
+++ b/ethcore/build.rs
@ -18,7 +18,7 @@ extern crate ethcore_ipc_codegen;

 fn main() {
 	ethcore_ipc_codegen::derive_binary("src/types/mod.rs.in").unwrap();
-	ethcore_ipc_codegen::derive_ipc("src/client/traits.rs").unwrap();
-	ethcore_ipc_codegen::derive_ipc("src/snapshot/snapshot_service_trait.rs").unwrap();
-	ethcore_ipc_codegen::derive_ipc("src/client/chain_notify.rs").unwrap();
+	ethcore_ipc_codegen::derive_ipc_cond("src/client/traits.rs", cfg!(feature="ipc")).unwrap();
+	ethcore_ipc_codegen::derive_ipc_cond("src/snapshot/snapshot_service_trait.rs", cfg!(feature="ipc")).unwrap();
+	ethcore_ipc_codegen::derive_ipc_cond("src/client/chain_notify.rs", cfg!(feature="ipc")).unwrap();
 }
--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@ -149,13 +149,6 @@ pub struct Client {
 /// assume finality of a given candidate.
 pub const HISTORY: u64 = 1200;

-/// Append a path element to the given path and return the string.
-pub fn append_path<P>(path: P, item: &str) -> String where P: AsRef<Path> {
-	let mut p = path.as_ref().to_path_buf();
-	p.push(item);
-	p.to_str().unwrap().to_owned()
-}
-
 impl Client {
 	/// Create a new client with given spec and DB path and custom verifier.
 	pub fn new(
@ -169,7 +162,7 @@ impl Client {
 		let path = path.to_path_buf();
 		let gb = spec.genesis_block();

-		let db = Arc::new(try!(Database::open(&db_config, &path.to_str().unwrap()).map_err(ClientError::Database)));
+		let db = Arc::new(try!(Database::open(&db_config, &path.to_str().expect("DB path could not be converted to string.")).map_err(ClientError::Database)));
 		let chain = Arc::new(BlockChain::new(config.blockchain.clone(), &gb, db.clone(), spec.engine.clone()));
 		let tracedb = RwLock::new(TraceDB::new(config.tracing.clone(), db.clone(), chain.clone()));

@ -298,31 +291,27 @@ impl Client {

 		// Check if Parent is in chain
 		let chain_has_parent = chain.block_header(header.parent_hash());
-		if let None = chain_has_parent {
+		if let Some(parent) = chain_has_parent {
+			// Enact Verified Block
+			let last_hashes = self.build_last_hashes(header.parent_hash().clone());
+			let db = self.state_db.lock().boxed_clone_canon(&header.parent_hash());
+
+			let enact_result = enact_verified(block, engine, self.tracedb.read().tracing_enabled(), db, &parent, last_hashes, self.factories.clone());
+			let locked_block = try!(enact_result.map_err(|e| {
+				warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
+			}));
+
+			// Final Verification
+			if let Err(e) = self.verifier.verify_block_final(header, locked_block.block().header()) {
+				warn!(target: "client", "Stage 4 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
+				return Err(());
+			}
+
+			Ok(locked_block)
+		} else {
 			warn!(target: "client", "Block import failed for #{} ({}): Parent not found ({}) ", header.number(), header.hash(), header.parent_hash());
-			return Err(());
-		};
-
-		// Enact Verified Block
-		let parent = chain_has_parent.unwrap();
-		let last_hashes = self.build_last_hashes(header.parent_hash().clone());
-		let is_canon = header.parent_hash() == &chain.best_block_hash();
-		let db = if is_canon { self.state_db.lock().boxed_clone_canon() } else { self.state_db.lock().boxed_clone() };
-
-		let enact_result = enact_verified(block, engine, self.tracedb.read().tracing_enabled(), db, &parent, last_hashes, self.factories.clone());
-		if let Err(e) = enact_result {
-			warn!(target: "client", "Block import failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
-			return Err(());
-		};
-
-		// Final Verification
-		let locked_block = enact_result.unwrap();
-		if let Err(e) = self.verifier.verify_block_final(header, locked_block.block().header()) {
-			warn!(target: "client", "Stage 4 block verification failed for #{} ({})\nError: {:?}", header.number(), header.hash(), e);
-			return Err(());
+			Err(())
 		}
-
-		Ok(locked_block)
 	}

 	fn calculate_enacted_retracted(&self, import_results: &[ImportRoute]) -> (Vec<H256>, Vec<H256>) {
@ -366,23 +355,21 @@ impl Client {

 			for block in blocks {
 				let header = &block.header;
-				if invalid_blocks.contains(header.parent_hash()) {
+				let is_invalid = invalid_blocks.contains(header.parent_hash());
+				if is_invalid {
 					invalid_blocks.insert(header.hash());
 					continue;
 				}
-				let closed_block = self.check_and_close_block(&block);
-				if let Err(_) = closed_block {
+				if let Ok(closed_block) = self.check_and_close_block(&block) {
+					imported_blocks.push(header.hash());
+
+					let route = self.commit_block(closed_block, &header.hash(), &block.bytes);
+					import_results.push(route);
+
+					self.report.write().accrue_block(&block);
+				} else {
 					invalid_blocks.insert(header.hash());
-					continue;
 				}
-
-				let closed_block = closed_block.unwrap();
-				imported_blocks.push(header.hash());
-
-				let route = self.commit_block(closed_block, &header.hash(), &block.bytes);
-				import_results.push(route);
-
-				self.report.write().accrue_block(&block);
 			}

 			let imported = imported_blocks.len();
@ -432,7 +419,7 @@ impl Client {
 		// Are we committing an era?
 		let ancient = if number >= HISTORY {
 			let n = number - HISTORY;
-			Some((n, chain.block_hash(n).unwrap()))
+			Some((n, chain.block_hash(n).expect("only verified blocks can be commited; verified block has hash; qed")))
 		} else {
 			None
 		};
@ -461,6 +448,8 @@ impl Client {
 			enacted: route.enacted.clone(),
 			retracted: route.retracted.len()
 		});
+		let is_canon = route.enacted.last().map_or(false, |h| h == hash);
+		state.sync_cache(&route.enacted, &route.retracted, is_canon);
 		// Final commit to the DB
 		self.db.read().write_buffered(batch);
 		chain.commit();
@ -535,9 +524,11 @@ impl Client {

 	/// Get a copy of the best block's state.
 	pub fn state(&self) -> State {
+		let header = self.best_block_header();
+		let header = HeaderView::new(&header);
 		State::from_existing(
-			self.state_db.lock().boxed_clone(),
-			HeaderView::new(&self.best_block_header()).state_root(),
+			self.state_db.lock().boxed_clone_canon(&header.hash()),
+			header.state_root(),
 			self.engine.account_start_nonce(),
 			self.factories.clone())
 		.expect("State root of best block header always valid.")
@ -899,8 +890,10 @@ impl BlockChainClient for Client {
 					BodyView::new(&block).localized_transaction_at(&address.block_hash, block_number, address.index)
 				});

-			match (t, chain.transaction_receipt(&address)) {
-				(Some(tx), Some(receipt)) => {
+			let tx_and_sender = t.and_then(|tx| tx.sender().ok().map(|sender| (tx, sender)));
+
+			match (tx_and_sender, chain.transaction_receipt(&address)) {
+				(Some((tx, sender)), Some(receipt)) => {
 					let block_hash = tx.block_hash.clone();
 					let block_number = tx.block_number.clone();
 					let transaction_hash = tx.hash();
@ -922,7 +915,7 @@ impl BlockChainClient for Client {
 						gas_used: receipt.gas_used - prior_gas_used,
 						contract_address: match tx.action {
 							Action::Call(_) => None,
-							Action::Create => Some(contract_address(&tx.sender().unwrap(), &tx.nonce))
+							Action::Create => Some(contract_address(&sender, &tx.nonce))
 						},
 						logs: receipt.logs.into_iter().enumerate().map(|(i, log)| LocalizedLogEntry {
 							entry: log,
@ -1023,17 +1016,18 @@ impl BlockChainClient for Client {
 		let start = self.block_number(filter.range.start);
 		let end = self.block_number(filter.range.end);

-		if start.is_some() && end.is_some() {
-			let filter = trace::Filter {
-				range: start.unwrap() as usize..end.unwrap() as usize,
-				from_address: From::from(filter.from_address),
-				to_address: From::from(filter.to_address),
-			};
+		match (start, end) {
+			(Some(s), Some(e)) => {
+				let filter = trace::Filter {
+					range: s as usize..e as usize,
+					from_address: From::from(filter.from_address),
+					to_address: From::from(filter.to_address),
+				};

-			let traces = self.tracedb.read().filter(&filter);
-			Some(traces)
-		} else {
-			None
+				let traces = self.tracedb.read().filter(&filter);
+				Some(traces)
+			},
+			_ => None,
 		}
 	}

@ -1080,7 +1074,7 @@ impl BlockChainClient for Client {
 	}

 	fn pending_transactions(&self) -> Vec<SignedTransaction> {
-		self.miner.pending_transactions()
+		self.miner.pending_transactions(self.chain.read().best_block_number())
 	}

 	// TODO: Make it an actual queue, return errors.
@ -1109,7 +1103,7 @@ impl MiningBlockChainClient for Client {
 			engine,
 			self.factories.clone(),
 			false,	// TODO: this will need to be parameterised once we want to do immediate mining insertion.
-			self.state_db.lock().boxed_clone(),
+			self.state_db.lock().boxed_clone_canon(&h),
 			&chain.block_header(&h).expect("h is best block hash: so its header must exist: qed"),
 			self.build_last_hashes(h.clone()),
 			author,
@ -1120,11 +1114,15 @@ impl MiningBlockChainClient for Client {
 		// Add uncles
 		chain
 			.find_uncle_headers(&h, engine.maximum_uncle_age())
-			.unwrap()
+			.unwrap_or_else(Vec::new)
 			.into_iter()
 			.take(engine.maximum_uncle_count())
 			.foreach(|h| {
-				open_block.push_uncle(h).unwrap();
+				open_block.push_uncle(h).expect("pushing maximum_uncle_count;
+												open_block was just created;
+												push_uncle is not ok only if more than maximum_uncle_count is pushed;
+												so all push_uncle are Ok;
+												qed");
 			});

 		open_block
@ -1145,6 +1143,7 @@ impl MiningBlockChainClient for Client {
 		let block_data = block.rlp_bytes();
 		let route = self.commit_block(block, &h, &block_data);
 		trace!(target: "client", "Imported sealed block #{} ({})", number, h);
+		self.state_db.lock().sync_cache(&route.enacted, &route.retracted, false);

 		let (enacted, retracted) = self.calculate_enacted_retracted(&[route]);
 		self.miner.chain_new_blocks(self, &[h.clone()], &[], &enacted, &retracted);
--- a/ethcore/src/client/mod.rs
+++ b/ethcore/src/client/mod.rs
@ -30,13 +30,20 @@ pub use self::test_client::{TestBlockChainClient, EachBlockWith};
 pub use types::trace_filter::Filter as TraceFilter;
 pub use executive::{Executed, Executive, TransactOptions};
 pub use env_info::{LastHashes, EnvInfo};
-pub use self::chain_notify::{ChainNotify, ChainNotifyClient};
+pub use self::chain_notify::ChainNotify;

 pub use types::call_analytics::CallAnalytics;
 pub use block_import_error::BlockImportError;
 pub use transaction_import::TransactionImportResult;
 pub use transaction_import::TransactionImportError;
-pub use self::traits::{BlockChainClient, MiningBlockChainClient, RemoteClient};
+pub use self::traits::{BlockChainClient, MiningBlockChainClient};
+
+/// IPC interfaces
+#[cfg(feature="ipc")]
+pub mod remote {
+	pub use super::traits::RemoteClient;
+	pub use super::chain_notify::ChainNotifyClient;
+}

 mod traits {
 	#![allow(dead_code, unused_assignments, unused_variables, missing_docs)] // codegen issues
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@ -55,6 +55,8 @@ pub struct TestBlockChainClient {
 	pub genesis_hash: H256,
 	/// Last block hash.
 	pub last_hash: RwLock<H256>,
+	/// Extra data do set for each block
+	pub extra_data: Bytes,
 	/// Difficulty.
 	pub difficulty: RwLock<U256>,
 	/// Balances.
@ -105,11 +107,17 @@ impl Default for TestBlockChainClient {
 impl TestBlockChainClient {
 	/// Creates new test client.
 	pub fn new() -> Self {
+		Self::new_with_extra_data(Bytes::new())
+	}
+
+	/// Creates new test client with specified extra data for each block
+	pub fn new_with_extra_data(extra_data: Bytes) -> Self {
 		let spec = Spec::new_test();
 		let mut client = TestBlockChainClient {
 			blocks: RwLock::new(HashMap::new()),
 			numbers: RwLock::new(HashMap::new()),
 			genesis_hash: H256::new(),
+			extra_data: extra_data,
 			last_hash: RwLock::new(H256::new()),
 			difficulty: RwLock::new(From::from(0)),
 			balances: RwLock::new(HashMap::new()),
@ -129,7 +137,7 @@ impl TestBlockChainClient {
 		client.genesis_hash = client.last_hash.read().clone();
 		client
 	}
-
+	
 	/// Set the transaction receipt result
 	pub fn set_transaction_receipt(&self, id: TransactionID, receipt: LocalizedReceipt) {
 		self.receipts.write().insert(id, receipt);
@ -184,6 +192,7 @@ impl TestBlockChainClient {
 			header.set_parent_hash(self.last_hash.read().clone());
 			header.set_number(n as BlockNumber);
 			header.set_gas_limit(U256::from(1_000_000));
+			header.set_extra_data(self.extra_data.clone());
 			let uncles = match with {
 				EachBlockWith::Uncle | EachBlockWith::UncleAndTransaction => {
 					let mut uncles = RlpStream::new_list(1);
@ -606,6 +615,6 @@ impl BlockChainClient for TestBlockChainClient {
 	}

 	fn pending_transactions(&self) -> Vec<SignedTransaction> {
-		self.miner.pending_transactions()
+		self.miner.pending_transactions(self.chain_info().best_block_number)
 	}
 }
--- a/ethcore/src/engines/tendermint/mod.rs
+++ b/ethcore/src/engines/tendermint/mod.rs
@ -20,6 +20,7 @@ mod message;
 mod timeout;
 mod params;
 mod vote;
+mod vote_collector;

 use std::sync::atomic::{AtomicUsize, Ordering as AtomicOrdering};
 use common::*;
@ -246,9 +247,11 @@ impl Engine for Tendermint {
 		}
 	}

-	/// Set author to proposer.
+	/// Set author to proposer and set the correct round in the seal.
 	/// This assumes that all uncles are valid uncles (i.e. of at least one generation before the current).
-	fn on_close_block(&self, _block: &mut ExecutedBlock) {}
+	fn on_close_block(&self, _block: &mut ExecutedBlock) {
+		
+	}

 	/// Attempt to seal the block internally using all available signatures.
 	///
@ -278,11 +281,14 @@ impl Engine for Tendermint {

 	fn handle_message(&self, sender: Address, signature: H520, message: UntrustedRlp) -> Result<Bytes, Error> {
 		let message: ConsensusMessage = try!(message.as_val());
-		try!(Err(EngineError::UnknownStep))
-		//match message {
-		//	ConsensusMessage::Prevote 
-		//}

+		if self.is_authority(&sender) {
+			//match message {
+			//		ConsensusMessage::Prevote 
+			//}
+		}
+
+		try!(Err(EngineError::UnknownStep))

 		// Check if correct round.
 		//if self.r.load(AtomicOrdering::Relaxed) != try!(message.val_at(0)) {
--- a/ethcore/src/engines/tendermint/vote.rs
+++ b/ethcore/src/engines/tendermint/vote.rs
@ -21,27 +21,35 @@ use util::Hashable;
 use account_provider::AccountProvider;
 use rlp::{View, DecoderError, Decodable, Decoder, Encodable, RlpStream, Stream};
 use basic_types::Seal;
+use super::BlockHash;

-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq, Hash)]
 pub struct Vote {
+	block_hash: BlockHash,
 	signature: H520
 }

-fn message(header: &Header) -> H256 {
+fn block_hash(header: &Header) -> H256 {
 	header.rlp(Seal::WithSome(1)).sha3()
 }

 impl Vote {
-	fn new(signature: H520) -> Vote { Vote { signature: signature }}
+	fn new(block_hash: BlockHash, signature: H520) -> Vote {
+		Vote { block_hash: block_hash, signature: signature }
+	}

 	/// Try to use the author address to create a vote.
 	pub fn propose(header: &Header, accounts: &AccountProvider) -> Option<Vote> {
-		accounts.sign(*header.author(), message(&header)).ok().map(Into::into).map(Self::new)
+		Self::validate(header, accounts, *header.author())
 	}
 	
 	/// Use any unlocked validator account to create a vote.
 	pub fn validate(header: &Header, accounts: &AccountProvider, validator: Address) -> Option<Vote> {
-		accounts.sign(validator, message(&header)).ok().map(Into::into).map(Self::new)
+		let message = block_hash(&header);
+		accounts.sign(validator, message)
+			.ok()
+			.map(Into::into)
+			.map(|sig| Self::new(message, sig))
 	}
 }

@ -51,13 +59,14 @@ impl Decodable for Vote {
 		if decoder.as_raw().len() != try!(rlp.payload_info()).total() {
 			return Err(DecoderError::RlpIsTooBig);
 		}
-		rlp.as_val().map(Self::new)
+		Ok(Self::new(try!(rlp.val_at(0)), try!(rlp.val_at(1))))
    }
 }

 impl Encodable for Vote {
 	fn rlp_append(&self, s: &mut RlpStream) {
-		let Vote { ref signature } = *self;
+		let Vote { ref block_hash, ref signature } = *self;
+		s.append(block_hash);
 		s.append(signature);
 	}
 }
--- a/ethcore/src/evm/interpreter/mod.rs
+++ b/ethcore/src/evm/interpreter/mod.rs
@ -116,11 +116,11 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 			let instruction = code[reader.position];
 			reader.position += 1;

-			let info = infos[instruction as usize];
-			try!(self.verify_instruction(ext, instruction, &info, &stack));
+			let info = &infos[instruction as usize];
+			try!(self.verify_instruction(ext, instruction, info, &stack));

 			// Calculate gas cost
-			let (gas_cost, mem_gas, mem_size) = try!(gasometer.get_gas_cost_mem(ext, instruction, &info, &stack, self.mem.size()));
+			let (gas_cost, mem_gas, mem_size) = try!(gasometer.get_gas_cost_mem(ext, instruction, info, &stack, self.mem.size()));
 			// TODO: make compile-time removable if too much of a performance hit.
 			let trace_executed = ext.trace_prepare_execute(reader.position - 1, instruction, &gas_cost.as_u256());

@ -129,7 +129,7 @@ impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
 			gasometer.current_mem_gas = mem_gas;
 			gasometer.current_gas = gasometer.current_gas - gas_cost;

-			evm_debug!({ informant.before_instruction(reader.position, instruction, &info, &gasometer.current_gas, &stack) });
+			evm_debug!({ informant.before_instruction(reader.position, instruction, info, &gasometer.current_gas, &stack) });

 			let (mem_written, store_written) = match trace_executed {
 				true => (Self::mem_written(instruction, &stack), Self::store_written(instruction, &stack)),
--- a/ethcore/src/evm/interpreter/shared_cache.rs
+++ b/ethcore/src/evm/interpreter/shared_cache.rs
@ -21,7 +21,7 @@ use util::sha3::*;
 use bit_set::BitSet;
 use super::super::instructions;

-const CACHE_CODE_ITEMS: usize = 4096;
+const CACHE_CODE_ITEMS: usize = 65536;

 /// GLobal cache for EVM interpreter
 pub struct SharedCache {
--- a/ethcore/src/executive.rs
+++ b/ethcore/src/executive.rs
@ -25,10 +25,10 @@ use trace::{FlatTrace, Tracer, NoopTracer, ExecutiveTracer, VMTrace, VMTracer, E
 use crossbeam;
 pub use types::executed::{Executed, ExecutionResult};

-/// Max depth to avoid stack overflow (when it's reached we start a new thread with VM)
+/// Roughly estimate what stack size each level of evm depth will use
 /// TODO [todr] We probably need some more sophisticated calculations here (limit on my machine 132)
 /// Maybe something like here: `https://github.com/ethereum/libethereum/blob/4db169b8504f2b87f7d5a481819cfb959fc65f6c/libethereum/ExtVM.cpp`
-const MAX_VM_DEPTH_FOR_THREAD: usize = 64;
+const STACK_SIZE_PER_DEPTH: usize = 24*1024;

 /// Returns new address created from address and given nonce.
 pub fn contract_address(address: &Address, nonce: &U256) -> Address {
@ -149,12 +149,13 @@ impl<'a> Executive<'a> {

 		// TODO: we might need bigints here, or at least check overflows.
 		let balance = self.state.balance(&sender);
-		let gas_cost = U512::from(t.gas) * U512::from(t.gas_price);
+		let gas_cost = t.gas.full_mul(t.gas_price);
 		let total_cost = U512::from(t.value) + gas_cost;

 		// avoid unaffordable transactions
-		if U512::from(balance) < total_cost {
-			return Err(From::from(ExecutionError::NotEnoughCash { required: total_cost, got: U512::from(balance) }));
+		let balance512 = U512::from(balance);
+		if balance512 < total_cost {
+			return Err(From::from(ExecutionError::NotEnoughCash { required: total_cost, got: balance512 }));
 		}

 		// NOTE: there can be no invalid transactions from this point.
@ -212,8 +213,11 @@ impl<'a> Executive<'a> {
 		tracer: &mut T,
 		vm_tracer: &mut V
 	) -> evm::Result<U256> where T: Tracer, V: VMTracer {
+
+		let depth_threshold = ::io::LOCAL_STACK_SIZE.with(|sz| sz.get() / STACK_SIZE_PER_DEPTH);
+
 		// Ordinary execution - keep VM in same thread
-		if (self.depth + 1) % MAX_VM_DEPTH_FOR_THREAD != 0 {
+		if (self.depth + 1) % depth_threshold != 0 {
 			let vm_factory = self.vm_factory;
 			let mut ext = self.as_externalities(OriginInfo::from(&params), unconfirmed_substate, output_policy, tracer, vm_tracer);
 			trace!(target: "executive", "ext.schedule.have_delegate_call: {}", ext.schedule().have_delegate_call);
@ -265,7 +269,7 @@ impl<'a> Executive<'a> {
 			let cost = self.engine.cost_of_builtin(&params.code_address, data);
 			if cost <= params.gas {
 				self.engine.execute_builtin(&params.code_address, data, &mut output);
-				self.state.clear_snapshot();
+				self.state.discard_snapshot();

 				// trace only top level calls to builtins to avoid DDoS attacks
 				if self.depth == 0 {
@ -285,7 +289,7 @@ impl<'a> Executive<'a> {
 				Ok(params.gas - cost)
 			} else {
 				// just drain the whole gas
-				self.state.revert_snapshot();
+				self.state.revert_to_snapshot();

 				tracer.trace_failed_call(trace_info, vec![], evm::Error::OutOfGas.into());

@ -331,7 +335,7 @@ impl<'a> Executive<'a> {
 				res
 			} else {
 				// otherwise it's just a basic transaction, only do tracing, if necessary.
-				self.state.clear_snapshot();
+				self.state.discard_snapshot();

 				tracer.trace_call(trace_info, U256::zero(), trace_output, vec![]);
 				Ok(params.gas)
@ -413,7 +417,7 @@ impl<'a> Executive<'a> {

 		// real ammount to refund
 		let gas_left_prerefund = match result { Ok(x) => x, _ => 0.into() };
-		let refunded = cmp::min(refunds_bound, (t.gas - gas_left_prerefund) / U256::from(2));
+		let refunded = cmp::min(refunds_bound, (t.gas - gas_left_prerefund) >> 1);
 		let gas_left = gas_left_prerefund + refunded;

 		let gas_used = t.gas - gas_left;
@ -473,10 +477,10 @@ impl<'a> Executive<'a> {
 				| Err(evm::Error::BadInstruction {.. })
 				| Err(evm::Error::StackUnderflow {..})
 				| Err(evm::Error::OutOfStack {..}) => {
-					self.state.revert_snapshot();
+					self.state.revert_to_snapshot();
 			},
 			Ok(_) | Err(evm::Error::Internal) => {
-				self.state.clear_snapshot();
+				self.state.discard_snapshot();
 				substate.accrue(un_substate);
 			}
 		}
--- a/ethcore/src/miner/miner.rs
+++ b/ethcore/src/miner/miner.rs
@ -48,6 +48,17 @@ pub enum PendingSet {
 	SealingOrElseQueue,
 }

+/// Type of the gas limit to apply to the transaction queue.
+#[derive(Debug, PartialEq)]
+pub enum GasLimit {
+	/// Depends on the block gas limit and is updated with every block.
+	Auto,
+	/// No limit.
+	None,
+	/// Set to a fixed gas value.
+	Fixed(U256),
+}
+
 /// Configures the behaviour of the miner.
 #[derive(Debug, PartialEq)]
 pub struct MinerOptions {
@ -71,6 +82,8 @@ pub struct MinerOptions {
 	pub work_queue_size: usize,
 	/// Can we submit two different solutions for the same block and expect both to result in an import?
 	pub enable_resubmission: bool,
+	/// Global gas limit for all transaction in the queue except for local and retracted.
+	pub tx_queue_gas_limit: GasLimit,
 }

 impl Default for MinerOptions {
@ -81,11 +94,12 @@ impl Default for MinerOptions {
 			reseal_on_external_tx: false,
 			reseal_on_own_tx: true,
 			tx_gas_limit: !U256::zero(),
-			tx_queue_size: 1024,
+			tx_queue_size: 2048,
 			pending_set: PendingSet::AlwaysQueue,
 			reseal_min_period: Duration::from_secs(2),
 			work_queue_size: 20,
 			enable_resubmission: true,
+			tx_queue_gas_limit: GasLimit::Auto,
 		}
 	}
 }
@ -194,7 +208,11 @@ impl Miner {
 			true => None,
 			false => Some(WorkPoster::new(&options.new_work_notify))
 		};
-		let txq = Arc::new(Mutex::new(TransactionQueue::with_limits(options.tx_queue_size, options.tx_gas_limit)));
+		let gas_limit = match options.tx_queue_gas_limit {
+			GasLimit::Fixed(ref limit) => *limit,
+			_ => !U256::zero(),
+		};
+		let txq = Arc::new(Mutex::new(TransactionQueue::with_limits(options.tx_queue_size, gas_limit, options.tx_gas_limit)));
 		Miner {
 			transaction_queue: txq,
 			next_allowed_reseal: Mutex::new(Instant::now()),
@ -443,6 +461,10 @@ impl Miner {
 		let gas_limit = HeaderView::new(&chain.best_block_header()).gas_limit();
 		let mut queue = self.transaction_queue.lock();
 		queue.set_gas_limit(gas_limit);
+		if let GasLimit::Auto = self.options.tx_queue_gas_limit {
+			// Set total tx queue gas limit to be 2x the block gas limit.
+			queue.set_total_gas_limit(gas_limit << 1);
+		}
 	}

 	/// Returns true if we had to prepare new pending block.
@ -493,6 +515,21 @@ impl Miner {

 	/// Are we allowed to do a non-mandatory reseal?
 	fn tx_reseal_allowed(&self) -> bool { Instant::now() > *self.next_allowed_reseal.lock() }
+
+	fn from_pending_block<H, F, G>(&self, latest_block_number: BlockNumber, from_chain: F, map_block: G) -> H
+		where F: Fn() -> H, G: Fn(&ClosedBlock) -> H {
+		let sealing_work = self.sealing_work.lock();
+		sealing_work.queue.peek_last_ref().map_or_else(
+			|| from_chain(),
+			|b| {
+				if b.block().header().number() > latest_block_number {
+					map_block(b)
+				} else {
+					from_chain()
+				}
+			}
+		)
+	}
 }

 const SEALING_TIMEOUT_IN_BLOCKS : u64 = 5;
@ -565,29 +602,35 @@ impl MinerService for Miner {
 	}

 	fn balance(&self, chain: &MiningBlockChainClient, address: &Address) -> U256 {
-		let sealing_work = self.sealing_work.lock();
-		sealing_work.queue.peek_last_ref().map_or_else(
+		self.from_pending_block(
+			chain.chain_info().best_block_number,
 			|| chain.latest_balance(address),
 			|b| b.block().fields().state.balance(address)
 		)
 	}

 	fn storage_at(&self, chain: &MiningBlockChainClient, address: &Address, position: &H256) -> H256 {
-		let sealing_work = self.sealing_work.lock();
-		sealing_work.queue.peek_last_ref().map_or_else(
+		self.from_pending_block(
+			chain.chain_info().best_block_number,
 			|| chain.latest_storage_at(address, position),
 			|b| b.block().fields().state.storage_at(address, position)
 		)
 	}

 	fn nonce(&self, chain: &MiningBlockChainClient, address: &Address) -> U256 {
-		let sealing_work = self.sealing_work.lock();
-		sealing_work.queue.peek_last_ref().map_or_else(|| chain.latest_nonce(address), |b| b.block().fields().state.nonce(address))
+		self.from_pending_block(
+			chain.chain_info().best_block_number,
+			|| chain.latest_nonce(address),
+			|b| b.block().fields().state.nonce(address)
+		)
 	}

 	fn code(&self, chain: &MiningBlockChainClient, address: &Address) -> Option<Bytes> {
-		let sealing_work = self.sealing_work.lock();
-		sealing_work.queue.peek_last_ref().map_or_else(|| chain.latest_code(address), |b| b.block().fields().state.code(address).map(|c| (*c).clone()))
+		self.from_pending_block(
+			chain.chain_info().best_block_number,
+			|| chain.latest_code(address),
+			|b| b.block().fields().state.code(address).map(|c| (*c).clone())
+		)
 	}

 	fn set_author(&self, author: Address) {
@ -737,50 +780,74 @@ impl MinerService for Miner {
 		queue.top_transactions()
 	}

-	fn pending_transactions(&self) -> Vec<SignedTransaction> {
+	fn pending_transactions(&self, best_block: BlockNumber) -> Vec<SignedTransaction> {
 		let queue = self.transaction_queue.lock();
-		let sw = self.sealing_work.lock();
-		// TODO: should only use the sealing_work when it's current (it could be an old block)
-		let sealing_set = match sw.enabled {
-			true => sw.queue.peek_last_ref(),
-			false => None,
-		};
-		match (&self.options.pending_set, sealing_set) {
-			(&PendingSet::AlwaysQueue, _) | (&PendingSet::SealingOrElseQueue, None) => queue.top_transactions(),
-			(_, sealing) => sealing.map_or_else(Vec::new, |s| s.transactions().to_owned()),
+		match self.options.pending_set {
+			PendingSet::AlwaysQueue => queue.top_transactions(),
+			PendingSet::SealingOrElseQueue => {
+				self.from_pending_block(
+					best_block,
+					|| queue.top_transactions(),
+					|sealing| sealing.transactions().to_owned()
+				)
+			},
+			PendingSet::AlwaysSealing => {
+				self.from_pending_block(
+					best_block,
+					|| vec![],
+					|sealing| sealing.transactions().to_owned()
+				)
+			},
 		}
 	}

-	fn pending_transactions_hashes(&self) -> Vec<H256> {
+	fn pending_transactions_hashes(&self, best_block: BlockNumber) -> Vec<H256> {
 		let queue = self.transaction_queue.lock();
-		let sw = self.sealing_work.lock();
-		let sealing_set = match sw.enabled {
-			true => sw.queue.peek_last_ref(),
-			false => None,
-		};
-		match (&self.options.pending_set, sealing_set) {
-			(&PendingSet::AlwaysQueue, _) | (&PendingSet::SealingOrElseQueue, None) => queue.pending_hashes(),
-			(_, sealing) => sealing.map_or_else(Vec::new, |s| s.transactions().iter().map(|t| t.hash()).collect()),
+		match self.options.pending_set {
+			PendingSet::AlwaysQueue => queue.pending_hashes(),
+			PendingSet::SealingOrElseQueue => {
+				self.from_pending_block(
+					best_block,
+					|| queue.pending_hashes(),
+					|sealing| sealing.transactions().iter().map(|t| t.hash()).collect()
+				)
+			},
+			PendingSet::AlwaysSealing => {
+				self.from_pending_block(
+					best_block,
+					|| vec![],
+					|sealing| sealing.transactions().iter().map(|t| t.hash()).collect()
+				)
+			},
 		}
 	}

-	fn transaction(&self, hash: &H256) -> Option<SignedTransaction> {
+	fn transaction(&self, best_block: BlockNumber, hash: &H256) -> Option<SignedTransaction> {
 		let queue = self.transaction_queue.lock();
-		let sw = self.sealing_work.lock();
-		let sealing_set = match sw.enabled {
-			true => sw.queue.peek_last_ref(),
-			false => None,
-		};
-		match (&self.options.pending_set, sealing_set) {
-			(&PendingSet::AlwaysQueue, _) | (&PendingSet::SealingOrElseQueue, None) => queue.find(hash),
-			(_, sealing) => sealing.and_then(|s| s.transactions().iter().find(|t| &t.hash() == hash).cloned()),
+		match self.options.pending_set {
+			PendingSet::AlwaysQueue => queue.find(hash),
+			PendingSet::SealingOrElseQueue => {
+				self.from_pending_block(
+					best_block,
+					|| queue.find(hash),
+					|sealing| sealing.transactions().iter().find(|t| &t.hash() == hash).cloned()
+				)
+			},
+			PendingSet::AlwaysSealing => {
+				self.from_pending_block(
+					best_block,
+					|| None,
+					|sealing| sealing.transactions().iter().find(|t| &t.hash() == hash).cloned()
+				)
+			},
 		}
 	}

-	fn pending_receipt(&self, hash: &H256) -> Option<RichReceipt> {
-		let sealing_work = self.sealing_work.lock();
-		match (sealing_work.enabled, sealing_work.queue.peek_last_ref()) {
-			(true, Some(pending)) => {
+	fn pending_receipt(&self, best_block: BlockNumber, hash: &H256) -> Option<RichReceipt> {
+		self.from_pending_block(
+			best_block,
+			|| None,
+			|pending| {
 				let txs = pending.transactions();
 				txs.iter()
 					.map(|t| t.hash())
@ -801,15 +868,15 @@ impl MinerService for Miner {
 							logs: receipt.logs.clone(),
 						}
 					})
-			},
-			_ => None
-		}
+			}
+		)
 	}

-	fn pending_receipts(&self) -> BTreeMap<H256, Receipt> {
-		let sealing_work = self.sealing_work.lock();
-		match (sealing_work.enabled, sealing_work.queue.peek_last_ref()) {
-			(true, Some(pending)) => {
+	fn pending_receipts(&self, best_block: BlockNumber) -> BTreeMap<H256, Receipt> {
+		self.from_pending_block(
+			best_block,
+			|| BTreeMap::new(),
+			|pending| {
 				let hashes = pending.transactions()
 					.iter()
 					.map(|t| t.hash());
@ -817,9 +884,8 @@ impl MinerService for Miner {
 				let receipts = pending.receipts().iter().cloned();

 				hashes.zip(receipts).collect()
-			},
-			_ => BTreeMap::new()
-		}
+			}
+		)
 	}

 	fn last_nonce(&self, address: &Address) -> Option<U256> {
@ -1016,6 +1082,7 @@ mod tests {
 				reseal_min_period: Duration::from_secs(5),
 				tx_gas_limit: !U256::zero(),
 				tx_queue_size: 1024,
+				tx_queue_gas_limit: GasLimit::None,
 				pending_set: PendingSet::AlwaysSealing,
 				work_queue_size: 5,
 				enable_resubmission: true,
@ -1044,34 +1111,54 @@ mod tests {
 		let client = TestBlockChainClient::default();
 		let miner = miner();
 		let transaction = transaction();
+		let best_block = 0;
 		// when
 		let res = miner.import_own_transaction(&client, transaction);

 		// then
 		assert_eq!(res.unwrap(), TransactionImportResult::Current);
 		assert_eq!(miner.all_transactions().len(), 1);
-		assert_eq!(miner.pending_transactions().len(), 1);
-		assert_eq!(miner.pending_transactions_hashes().len(), 1);
-		assert_eq!(miner.pending_receipts().len(), 1);
+		assert_eq!(miner.pending_transactions(best_block).len(), 1);
+		assert_eq!(miner.pending_transactions_hashes(best_block).len(), 1);
+		assert_eq!(miner.pending_receipts(best_block).len(), 1);
 		// This method will let us know if pending block was created (before calling that method)
 		assert!(!miner.prepare_work_sealing(&client));
 	}

+	#[test]
+	fn should_not_use_pending_block_if_best_block_is_higher() {
+		// given
+		let client = TestBlockChainClient::default();
+		let miner = miner();
+		let transaction = transaction();
+		let best_block = 10;
+		// when
+		let res = miner.import_own_transaction(&client, transaction);
+
+		// then
+		assert_eq!(res.unwrap(), TransactionImportResult::Current);
+		assert_eq!(miner.all_transactions().len(), 1);
+		assert_eq!(miner.pending_transactions(best_block).len(), 0);
+		assert_eq!(miner.pending_transactions_hashes(best_block).len(), 0);
+		assert_eq!(miner.pending_receipts(best_block).len(), 0);
+	}
+
 	#[test]
 	fn should_import_external_transaction() {
 		// given
 		let client = TestBlockChainClient::default();
 		let miner = miner();
 		let transaction = transaction();
+		let best_block = 0;
 		// when
 		let res = miner.import_external_transactions(&client, vec![transaction]).pop().unwrap();

 		// then
 		assert_eq!(res.unwrap(), TransactionImportResult::Current);
 		assert_eq!(miner.all_transactions().len(), 1);
-		assert_eq!(miner.pending_transactions_hashes().len(), 0);
-		assert_eq!(miner.pending_transactions().len(), 0);
-		assert_eq!(miner.pending_receipts().len(), 0);
+		assert_eq!(miner.pending_transactions_hashes(best_block).len(), 0);
+		assert_eq!(miner.pending_transactions(best_block).len(), 0);
+		assert_eq!(miner.pending_receipts(best_block).len(), 0);
 		// This method will let us know if pending block was created (before calling that method)
 		assert!(miner.prepare_work_sealing(&client));
 	}
--- a/ethcore/src/miner/mod.rs
+++ b/ethcore/src/miner/mod.rs
@ -48,7 +48,7 @@ mod work_notify;
 mod price_info;

 pub use self::transaction_queue::{TransactionQueue, AccountDetails, TransactionOrigin};
-pub use self::miner::{Miner, MinerOptions, PendingSet, GasPricer, GasPriceCalibratorOptions};
+pub use self::miner::{Miner, MinerOptions, PendingSet, GasPricer, GasPriceCalibratorOptions, GasLimit};
 pub use self::external::{ExternalMiner, ExternalMinerService};
 pub use client::TransactionImportResult;

@ -56,6 +56,7 @@ use std::collections::BTreeMap;
 use util::{H256, U256, Address, Bytes};
 use client::{MiningBlockChainClient, Executed, CallAnalytics};
 use block::ClosedBlock;
+use header::BlockNumber;
 use receipt::{RichReceipt, Receipt};
 use error::{Error, CallError};
 use transaction::SignedTransaction;
@ -115,7 +116,7 @@ pub trait MinerService : Send + Sync {
 		Result<TransactionImportResult, Error>;

 	/// Returns hashes of transactions currently in pending
-	fn pending_transactions_hashes(&self) -> Vec<H256>;
+	fn pending_transactions_hashes(&self, best_block: BlockNumber) -> Vec<H256>;

 	/// Removes all transactions from the queue and restart mining operation.
 	fn clear_and_reset(&self, chain: &MiningBlockChainClient);
@ -135,19 +136,19 @@ pub trait MinerService : Send + Sync {
 		where F: FnOnce(&ClosedBlock) -> T, Self: Sized;

 	/// Query pending transactions for hash.
-	fn transaction(&self, hash: &H256) -> Option<SignedTransaction>;
+	fn transaction(&self, best_block: BlockNumber, hash: &H256) -> Option<SignedTransaction>;

 	/// Get a list of all transactions.
 	fn all_transactions(&self) -> Vec<SignedTransaction>;

 	/// Get a list of all pending transactions.
-	fn pending_transactions(&self) -> Vec<SignedTransaction>;
+	fn pending_transactions(&self, best_block: BlockNumber) -> Vec<SignedTransaction>;

 	/// Get a list of all pending receipts.
-	fn pending_receipts(&self) -> BTreeMap<H256, Receipt>;
+	fn pending_receipts(&self, best_block: BlockNumber) -> BTreeMap<H256, Receipt>;

 	/// Get a particular reciept.
-	fn pending_receipt(&self, hash: &H256) -> Option<RichReceipt>;
+	fn pending_receipt(&self, best_block: BlockNumber, hash: &H256) -> Option<RichReceipt>;

 	/// Returns highest transaction nonce for given address.
 	fn last_nonce(&self, address: &Address) -> Option<U256>;
--- a/ethcore/src/miner/transaction_queue.rs
+++ b/ethcore/src/miner/transaction_queue.rs
@ -130,6 +130,8 @@ struct TransactionOrder {
 	/// (e.g. Tx(nonce:5), State(nonce:0) -> height: 5)
 	/// High nonce_height = Low priority (processed later)
 	nonce_height: U256,
+	/// Gas specified in the transaction.
+	gas: U256,
 	/// Gas Price of the transaction.
 	/// Low gas price = Low priority (processed later)
 	gas_price: U256,
@ -146,6 +148,7 @@ impl TransactionOrder {
 	fn for_transaction(tx: &VerifiedTransaction, base_nonce: U256) -> Self {
 		TransactionOrder {
 			nonce_height: tx.nonce() - base_nonce,
+			gas: tx.transaction.gas.clone(),
 			gas_price: tx.transaction.gas_price,
 			hash: tx.hash(),
 			origin: tx.origin,
@ -287,6 +290,7 @@ struct TransactionSet {
 	by_address: Table<Address, U256, TransactionOrder>,
 	by_gas_price: GasPriceQueue,
 	limit: usize,
+	gas_limit: U256,
 }

 impl TransactionSet {
@ -317,15 +321,20 @@ impl TransactionSet {
 	/// It drops transactions from this set but also removes associated `VerifiedTransaction`.
 	/// 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 mut count = 0;
+		let mut gas: U256 = 0.into();
 		let to_drop : Vec<(Address, U256)> = {
 			self.by_priority
 				.iter()
-				.skip(self.limit)
+				.skip_while(|order| {
+					count = count + 1;
+					let r = gas.overflowing_add(order.gas);
+					if r.1 { return false }
+					gas = r.0;
+					// Own and retracted transactions are allowed to go above the gas limit, bot not above the count limit.
+					(gas <= self.gas_limit || order.origin == TransactionOrigin::Local || order.origin == TransactionOrigin::RetractedBlock) &&
+						count <= self.limit
+				})
 				.map(|order| by_hash.get(&order.hash)
 					.expect("All transactions in `self.by_priority` and `self.by_address` are kept in sync with `by_hash`."))
 				.map(|tx| (tx.sender(), tx.nonce()))
@ -432,16 +441,17 @@ impl Default for TransactionQueue {
 impl TransactionQueue {
 	/// Creates new instance of this Queue
 	pub fn new() -> Self {
-		Self::with_limits(1024, !U256::zero())
+		Self::with_limits(1024, !U256::zero(), !U256::zero())
 	}

 	/// Create new instance of this Queue with specified limits
-	pub fn with_limits(limit: usize, tx_gas_limit: U256) -> Self {
+	pub fn with_limits(limit: usize, gas_limit: U256, tx_gas_limit: U256) -> Self {
 		let current = TransactionSet {
 			by_priority: BTreeSet::new(),
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
 			limit: limit,
+			gas_limit: gas_limit,
 		};

 		let future = TransactionSet {
@ -449,6 +459,7 @@ impl TransactionQueue {
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
 			limit: limit,
+			gas_limit: gas_limit,
 		};

 		TransactionQueue {
@ -504,6 +515,13 @@ impl TransactionQueue {
 		};
 	}

+	/// Sets new total gas limit.
+	pub fn set_total_gas_limit(&mut self, gas_limit: U256) {
+		self.future.gas_limit = gas_limit;
+		self.current.gas_limit = gas_limit;
+		self.future.enforce_limit(&mut self.by_hash);
+	}
+
 	/// Set the new limit for the amount of gas any individual transaction may have.
 	/// Any transaction already imported to the queue is not affected.
 	pub fn set_tx_gas_limit(&mut self, limit: U256) {
@ -636,7 +654,7 @@ impl TransactionQueue {
 		};
 		for k in nonces_from_sender {
 			let order = self.future.drop(&sender, &k).unwrap();
-			self.current.insert(sender, k, order.penalize());
+			self.future.insert(sender, k, order.penalize());
 		}
 	}

@ -735,6 +753,15 @@ impl TransactionQueue {
 			.collect()
 	}

+	#[cfg(test)]
+	fn future_transactions(&self) -> Vec<SignedTransaction> {
+		self.future.by_priority
+			.iter()
+			.map(|t| self.by_hash.get(&t.hash).expect("All transactions in `current` and `future` are always included in `by_hash`"))
+			.map(|t| t.transaction.clone())
+			.collect()
+	}
+
 	/// Returns hashes of all transactions from current, ordered by priority.
 	pub fn pending_hashes(&self) -> Vec<H256> {
 		self.current.by_priority
@ -818,6 +845,16 @@ impl TransactionQueue {
 		let nonce = tx.nonce();
 		let hash = tx.hash();

+		{
+			// Rough size sanity check
+			let gas = &tx.transaction.gas;
+			if U256::from(tx.transaction.data.len()) > *gas {
+				// Droping transaction
+				trace!(target: "txqueue", "Dropping oversized transaction: {:?} (gas: {} < size {})", hash, gas, tx.transaction.data.len());
+				return Err(TransactionError::LimitReached);
+			}
+		}
+
 		// The transaction might be old, let's check that.
 		// This has to be the first test, otherwise calculating
 		// nonce height would result in overflow.
@ -970,6 +1007,7 @@ mod test {
 	}

 	fn default_nonce() -> U256 { 123.into() }
+	fn default_gas_val() -> U256 { 100_000.into() }
 	fn default_gas_price() -> U256 { 1.into() }

 	fn new_unsigned_tx(nonce: U256, gas_price: U256) -> Transaction {
@ -977,7 +1015,7 @@ mod test {
 			action: Action::Create,
 			value: U256::from(100),
 			data: "3331600055".from_hex().unwrap(),
-			gas: U256::from(100_000),
+			gas: default_gas_val(),
 			gas_price: gas_price,
 			nonce: nonce
 		}
@ -1042,7 +1080,7 @@ mod test {
 	#[test]
 	fn should_return_correct_nonces_when_dropped_because_of_limit() {
 		// given
-		let mut txq = TransactionQueue::with_limits(2, !U256::zero());
+		let mut txq = TransactionQueue::with_limits(2, !U256::zero(), !U256::zero());
 		let (tx1, tx2) = new_tx_pair(123.into(), 1.into(), 1.into(), 0.into());
 		let sender = tx1.sender().unwrap();
 		let nonce = tx1.nonce;
@ -1080,7 +1118,8 @@ mod test {
 			by_priority: BTreeSet::new(),
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
-			limit: 1
+			limit: 1,
+			gas_limit: !U256::zero(),
 		};
 		let (tx1, tx2) = new_tx_pair_default(1.into(), 0.into());
 		let tx1 = VerifiedTransaction::new(tx1, TransactionOrigin::External).unwrap();
@ -1120,7 +1159,8 @@ mod test {
 			by_priority: BTreeSet::new(),
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
-			limit: 1
+			limit: 1,
+			gas_limit: !U256::zero(),
 		};
 		// Create two transactions with same nonce
 		// (same hash)
@ -1168,7 +1208,8 @@ mod test {
 			by_priority: BTreeSet::new(),
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
-			limit: 2
+			limit: 2,
+			gas_limit: !U256::zero(),
 		};
 		let tx = new_tx_default();
 		let tx1 = VerifiedTransaction::new(tx.clone(), TransactionOrigin::External).unwrap();
@ -1185,7 +1226,8 @@ mod test {
 			by_priority: BTreeSet::new(),
 			by_address: Table::new(),
 			by_gas_price: Default::default(),
-			limit: 1
+			limit: 1,
+			gas_limit: !U256::zero(),
 		};

 		assert_eq!(set.gas_price_entry_limit(), 0.into());
@ -1463,6 +1505,36 @@ mod test {
 		assert_eq!(top.len(), 2);
 	}

+	#[test]
+	fn should_penalize_transactions_from_sender_in_future() {
+		// given
+		let prev_nonce = |a: &Address| AccountDetails{ nonce: default_account_details(a).nonce - U256::one(), balance: !U256::zero() };
+		let mut txq = TransactionQueue::new();
+		// txa, txb - slightly bigger gas price to have consistent ordering
+		let (txa, txb) = new_tx_pair_default(1.into(), 0.into());
+		let (tx1, tx2) = new_tx_pair_with_gas_price_increment(3.into());
+
+		// insert everything
+		txq.add(txa.clone(), &prev_nonce, TransactionOrigin::External).unwrap();
+		txq.add(txb.clone(), &prev_nonce, TransactionOrigin::External).unwrap();
+		txq.add(tx1.clone(), &prev_nonce, TransactionOrigin::External).unwrap();
+		txq.add(tx2.clone(), &prev_nonce, TransactionOrigin::External).unwrap();
+
+		assert_eq!(txq.status().future, 4);
+
+		// when
+		txq.penalize(&tx1.hash());
+
+		// then
+		let top = txq.future_transactions();
+		assert_eq!(top[0], txa);
+		assert_eq!(top[1], txb);
+		assert_eq!(top[2], tx1);
+		assert_eq!(top[3], tx2);
+		assert_eq!(top.len(), 4);
+	}
+
+
 	#[test]
 	fn should_penalize_transactions_from_sender() {
 		// given
@ -1651,7 +1723,7 @@ mod test {
 	#[test]
 	fn should_drop_old_transactions_when_hitting_the_limit() {
 		// given
-		let mut txq = TransactionQueue::with_limits(1, !U256::zero());
+		let mut txq = TransactionQueue::with_limits(1, !U256::zero(), !U256::zero());
 		let (tx, tx2) = new_tx_pair_default(1.into(), 0.into());
 		let sender = tx.sender().unwrap();
 		let nonce = tx.nonce;
@ -1672,7 +1744,7 @@ mod test {

 	#[test]
 	fn should_limit_future_transactions() {
-		let mut txq = TransactionQueue::with_limits(1, !U256::zero());
+		let mut txq = TransactionQueue::with_limits(1, !U256::zero(), !U256::zero());
 		txq.current.set_limit(10);
 		let (tx1, tx2) = new_tx_pair_default(4.into(), 1.into());
 		let (tx3, tx4) = new_tx_pair_default(4.into(), 2.into());
@ -1689,6 +1761,30 @@ mod test {
 		assert_eq!(txq.status().future, 1);
 	}

+	#[test]
+	fn should_limit_by_gas() {
+		let mut txq = TransactionQueue::with_limits(100, default_gas_val() * U256::from(2), !U256::zero());
+		let (tx1, tx2) = new_tx_pair_default(U256::from(1), U256::from(1));
+		let (tx3, tx4) = new_tx_pair_default(U256::from(1), U256::from(2));
+		txq.add(tx1.clone(), &default_account_details, TransactionOrigin::External).ok();
+		txq.add(tx2.clone(), &default_account_details, TransactionOrigin::External).ok();
+		txq.add(tx3.clone(), &default_account_details, TransactionOrigin::External).ok();
+		txq.add(tx4.clone(), &default_account_details, TransactionOrigin::External).ok();
+		assert_eq!(txq.status().pending, 2);
+	}
+
+	#[test]
+	fn should_keep_own_transactions_above_gas_limit() {
+		let mut txq = TransactionQueue::with_limits(100, default_gas_val() * U256::from(2), !U256::zero());
+		let (tx1, tx2) = new_tx_pair_default(U256::from(1), U256::from(1));
+		let (tx3, tx4) = new_tx_pair_default(U256::from(1), U256::from(2));
+		txq.add(tx1.clone(), &default_account_details, TransactionOrigin::Local).unwrap();
+		txq.add(tx2.clone(), &default_account_details, TransactionOrigin::Local).unwrap();
+		txq.add(tx3.clone(), &default_account_details, TransactionOrigin::Local).unwrap();
+		txq.add(tx4.clone(), &default_account_details, TransactionOrigin::Local).unwrap();
+		assert_eq!(txq.status().pending, 4);
+	}
+
 	#[test]
 	fn should_drop_transactions_with_old_nonces() {
 		let mut txq = TransactionQueue::new();
@ -1932,7 +2028,7 @@ mod test {
 	#[test]
 	fn should_keep_right_order_in_future() {
 		// given
-		let mut txq = TransactionQueue::with_limits(1, !U256::zero());
+		let mut txq = TransactionQueue::with_limits(1, !U256::zero(), !U256::zero());
 		let (tx1, tx2) = new_tx_pair_default(1.into(), 0.into());
 		let prev_nonce = |a: &Address| AccountDetails { nonce: default_account_details(a).nonce - U256::one(), balance:
 			default_account_details(a).balance };
--- a/ethcore/src/snapshot/mod.rs
+++ b/ethcore/src/snapshot/mod.rs
@ -51,7 +51,7 @@ use rand::{Rng, OsRng};
 pub use self::error::Error;

 pub use self::service::{Service, DatabaseRestore};
-pub use self::traits::{SnapshotService, RemoteSnapshotService};
+pub use self::traits::SnapshotService;
 pub use self::watcher::Watcher;
 pub use types::snapshot_manifest::ManifestData;
 pub use types::restoration_status::RestorationStatus;
@ -67,6 +67,12 @@ mod watcher;
 #[cfg(test)]
 mod tests;

+/// IPC interfaces
+#[cfg(feature="ipc")]
+pub mod remote {
+	pub use super::traits::RemoteSnapshotService;
+}
+
 mod traits {
 	#![allow(dead_code, unused_assignments, unused_variables, missing_docs)] // codegen issues
 	include!(concat!(env!("OUT_DIR"), "/snapshot_service_trait.rs"));
--- a/ethcore/src/state/account.rs
+++ b/ethcore/src/state/account.rs
@ -16,7 +16,6 @@

 //! Single account in the system.

-use std::collections::hash_map::Entry;
 use util::*;
 use pod_account::*;
 use rlp::*;
@ -24,9 +23,11 @@ use lru_cache::LruCache;

 use std::cell::{RefCell, Cell};

-const STORAGE_CACHE_ITEMS: usize = 4096;
+const STORAGE_CACHE_ITEMS: usize = 8192;

 /// Single account in the system.
+/// Keeps track of changes to the code and storage.
+/// The changes are applied in `commit_storage` and `commit_code`
 pub struct Account {
 	// Balance of the account.
 	balance: U256,
@ -46,8 +47,6 @@ pub struct Account {
 	code_size: Option<usize>,
 	// Code cache of the account.
 	code_cache: Arc<Bytes>,
-	// Account is new or has been modified.
-	filth: Filth,
 	// Account code new or has been modified.
 	code_filth: Filth,
 	// Cached address hash.
@ -67,7 +66,6 @@ impl Account {
 			code_hash: code.sha3(),
 			code_size: Some(code.len()),
 			code_cache: Arc::new(code),
-			filth: Filth::Dirty,
 			code_filth: Filth::Dirty,
 			address_hash: Cell::new(None),
 		}
@ -89,7 +87,6 @@ impl Account {
 			code_filth: Filth::Dirty,
 			code_size: Some(pod.code.as_ref().map_or(0, |c| c.len())),
 			code_cache: Arc::new(pod.code.map_or_else(|| { warn!("POD account with unknown code is being created! Assuming no code."); vec![] }, |c| c)),
-			filth: Filth::Dirty,
 			address_hash: Cell::new(None),
 		}
 	}
@ -105,7 +102,6 @@ impl Account {
 			code_hash: SHA3_EMPTY,
 			code_cache: Arc::new(vec![]),
 			code_size: Some(0),
-			filth: Filth::Dirty,
 			code_filth: Filth::Clean,
 			address_hash: Cell::new(None),
 		}
@ -123,7 +119,6 @@ impl Account {
 			code_hash: r.val_at(3),
 			code_cache: Arc::new(vec![]),
 			code_size: None,
-			filth: Filth::Clean,
 			code_filth: Filth::Clean,
 			address_hash: Cell::new(None),
 		}
@ -141,7 +136,6 @@ impl Account {
 			code_hash: SHA3_EMPTY,
 			code_cache: Arc::new(vec![]),
 			code_size: None,
-			filth: Filth::Dirty,
 			code_filth: Filth::Clean,
 			address_hash: Cell::new(None),
 		}
@ -153,7 +147,6 @@ impl Account {
 		self.code_hash = code.sha3();
 		self.code_cache = Arc::new(code);
 		self.code_size = Some(self.code_cache.len());
-		self.filth = Filth::Dirty;
 		self.code_filth = Filth::Dirty;
 	}

@ -164,17 +157,7 @@ impl Account {

 	/// Set (and cache) the contents of the trie's storage at `key` to `value`.
 	pub fn set_storage(&mut self, key: H256, value: H256) {
-		match self.storage_changes.entry(key) {
-			Entry::Occupied(ref mut entry) if entry.get() != &value => {
-				entry.insert(value);
-				self.filth = Filth::Dirty;
-			},
-			Entry::Vacant(entry) => {
-				entry.insert(value);
-				self.filth = Filth::Dirty;
-			},
-			_ => {},
-		}
+		self.storage_changes.insert(key, value);
 	}

 	/// Get (and cache) the contents of the trie's storage at `key`.
@ -263,17 +246,6 @@ impl Account {
 		!self.code_cache.is_empty() || (self.code_cache.is_empty() && self.code_hash == SHA3_EMPTY)
 	}

-	/// Is this a new or modified account?
-	pub fn is_dirty(&self) -> bool {
-		self.filth == Filth::Dirty || self.code_filth == Filth::Dirty || !self.storage_is_clean()
-	}
-
-	/// Mark account as clean.
-	pub fn set_clean(&mut self) {
-		assert!(self.storage_is_clean());
-		self.filth = Filth::Clean
-	}
-
 	/// 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: &HashDB) -> bool {
 		// TODO: fill out self.code_cache;
@ -326,25 +298,18 @@ impl Account {
 	/// Increment the nonce of the account by one.
 	pub fn inc_nonce(&mut self) {
 		self.nonce = self.nonce + U256::from(1u8);
-		self.filth = Filth::Dirty;
 	}

-	/// Increment the nonce of the account by one.
+	/// Increase account balance.
 	pub fn add_balance(&mut self, x: &U256) {
-		if !x.is_zero() {
-			self.balance = self.balance + *x;
-			self.filth = Filth::Dirty;
-		}
+		self.balance = self.balance + *x;
 	}

-	/// Increment the nonce of the account by one.
+	/// Decrease account balance.
 	/// Panics if balance is less than `x`
 	pub fn sub_balance(&mut self, x: &U256) {
-		if !x.is_zero() {
-			assert!(self.balance >= *x);
-			self.balance = self.balance - *x;
-			self.filth = Filth::Dirty;
-		}
+		assert!(self.balance >= *x);
+		self.balance = self.balance - *x;
 	}

 	/// Commit the `storage_changes` to the backing DB and update `storage_root`.
@ -406,7 +371,6 @@ impl Account {
 			code_hash: self.code_hash.clone(),
 			code_size: self.code_size.clone(),
 			code_cache: self.code_cache.clone(),
-			filth: self.filth,
 			code_filth: self.code_filth,
 			address_hash: self.address_hash.clone(),
 		}
@ -427,10 +391,10 @@ impl Account {
 		account
 	}

-	/// Replace self with the data from other account merging storage cache
-	pub fn merge_with(&mut self, other: Account) {
-		assert!(self.storage_is_clean());
-		assert!(other.storage_is_clean());
+	/// Replace self with the data from other account merging storage cache.
+	/// Basic account data and all modifications are overwritten
+	/// with new values.
+	pub fn overwrite_with(&mut self, other: Account) {
 		self.balance = other.balance;
 		self.nonce = other.nonce;
 		self.storage_root = other.storage_root;
@ -443,6 +407,7 @@ impl Account {
 		for (k, v) in other.storage_cache.into_inner().into_iter() {
 			cache.insert(k.clone() , v.clone()); //TODO: cloning should not be required here
 		}
+		self.storage_changes = other.storage_changes;
 	}
 }

--- a/ethcore/src/state/mod.rs
+++ b/ethcore/src/state/mod.rs
@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

 use std::cell::{RefCell, RefMut};
+use std::collections::hash_map::Entry;
 use common::*;
 use engines::Engine;
 use executive::{Executive, TransactOptions};
@ -42,42 +43,93 @@ pub struct ApplyOutcome {
 /// Result type for the execution ("application") of a transaction.
 pub type ApplyResult = Result<ApplyOutcome, Error>;

-#[derive(Debug)]
-enum AccountEntry {
-	/// Contains account data.
-	Cached(Account),
-	/// Account has been deleted.
-	Killed,
-	/// Account does not exist.
-	Missing,
+#[derive(Eq, PartialEq, Clone, Copy, Debug)]
+/// Account modification state. Used to check if the account was
+/// Modified in between commits and overall.
+enum AccountState {
+	/// Account was loaded from disk and never modified in this state object.
+	CleanFresh,
+	/// Account was loaded from the global cache and never modified.
+	CleanCached,
+	/// Account has been modified and is not committed to the trie yet.
+	/// This is set if any of the account data is changed, including
+	/// storage and code.
+	Dirty,
+	/// Account was modified and committed to the trie.
+	Committed,
 }

+#[derive(Debug)]
+/// In-memory copy of the account data. Holds the optional account
+/// and the modification status.
+/// Account entry can contain existing (`Some`) or non-existing
+/// account (`None`)
+struct AccountEntry {
+	account: Option<Account>,
+	state: AccountState,
+}
+
+// Account cache item. Contains account data and
+// modification state
 impl AccountEntry {
 	fn is_dirty(&self) -> bool {
-		match *self {
-			AccountEntry::Cached(ref a) => a.is_dirty(),
-			AccountEntry::Killed => true,
-			AccountEntry::Missing => false,
-		}
+		self.state == AccountState::Dirty
 	}

-	/// Clone dirty data into new `AccountEntry`.
+	/// Clone dirty data into new `AccountEntry`. This includes
+	/// basic account data and modified storage keys.
 	/// Returns None if clean.
-	fn clone_dirty(&self) -> Option<AccountEntry> {
-		match *self {
-			AccountEntry::Cached(ref acc) if acc.is_dirty() => Some(AccountEntry::Cached(acc.clone_dirty())),
-			AccountEntry::Killed => Some(AccountEntry::Killed),
-			_ => None,
+	fn clone_if_dirty(&self) -> Option<AccountEntry> {
+		match self.is_dirty() {
+			true => Some(self.clone_dirty()),
+			false => None,
 		}
 	}

-	/// Clone account entry data that needs to be saved in the snapshot.
-	/// This includes basic account information and all locally cached storage keys
-	fn clone_for_snapshot(&self) -> AccountEntry {
-		match *self {
-			AccountEntry::Cached(ref acc) => AccountEntry::Cached(acc.clone_all()),
-			AccountEntry::Killed => AccountEntry::Killed,
-			AccountEntry::Missing => AccountEntry::Missing,
+	/// Clone dirty data into new `AccountEntry`. This includes
+	/// basic account data and modified storage keys.
+	fn clone_dirty(&self) -> AccountEntry {
+		AccountEntry {
+			account: self.account.as_ref().map(Account::clone_dirty),
+			state: self.state,
+		}
+	}
+
+	// Create a new account entry and mark it as dirty.
+	fn new_dirty(account: Option<Account>) -> AccountEntry {
+		AccountEntry {
+			account: account,
+			state: AccountState::Dirty,
+		}
+	}
+
+	// Create a new account entry and mark it as clean.
+	fn new_clean(account: Option<Account>) -> AccountEntry {
+		AccountEntry {
+			account: account,
+			state: AccountState::CleanFresh,
+		}
+	}
+
+	// Create a new account entry and mark it as clean and cached.
+	fn new_clean_cached(account: Option<Account>) -> AccountEntry {
+		AccountEntry {
+			account: account,
+			state: AccountState::CleanCached,
+		}
+	}
+
+	// Replace data with another entry but preserve storage cache.
+	fn overwrite_with(&mut self, other: AccountEntry) {
+		self.state = other.state;
+		match other.account {
+			Some(acc) => match self.account {
+				Some(ref mut ours) => {
+					ours.overwrite_with(acc);
+				},
+				None => {},
+			},
+			None => self.account = None,
 		}
 	}
 }
@ -90,6 +142,9 @@ impl AccountEntry {
 /// locally from previous commits. Global cache reflects the database
 /// state and never contains any changes.
 ///
+/// Cache items contains account data, or the flag that account does not exist
+/// and modification state (see `AccountState`)
+///
 /// Account data can be in the following cache states:
 /// * In global but not local - something that was queried from the database,
 /// but never modified
@ -103,12 +158,32 @@ impl AccountEntry {
 /// then global state cache. If data is not found in any of the caches
 /// it is loaded from the DB to the local cache.
 ///
-/// Upon destruction all the local cache data merged into the global cache.
-/// The merge might be rejected if current state is non-canonical.
+/// **** IMPORTANT *************************************************************
+/// All the modifications to the account data must set the `Dirty` state in the
+/// `AccountEntry`. This is done in `require` and `require_or_from`. So just
+/// use that.
+/// ****************************************************************************
+///
+/// Upon destruction all the local cache data propagated into the global cache.
+/// Propagated items might be rejected if current state is non-canonical.
+///
+/// State snapshotting.
+///
+/// A new snapshot can be created with `snapshot()`. Snapshots can be
+/// created in a hierarchy.
+/// When a snapshot is active all changes are applied directly into
+/// `cache` and the original value is copied into an active snapshot.
+/// Reverting a snapshot with `revert_to_snapshot` involves copying
+/// original values from the latest snapshot back into `cache`. The code
+/// takes care not to overwrite cached storage while doing that.
+/// Snapshot can be discateded with `discard_snapshot`. All of the orignal
+/// backed-up values are moved into a parent snapshot (if any).
+///
 pub struct State {
 	db: StateDB,
 	root: H256,
 	cache: RefCell<HashMap<Address, AccountEntry>>,
+	// The original account is preserved in
 	snapshots: RefCell<Vec<HashMap<Address, Option<AccountEntry>>>>,
 	account_start_nonce: U256,
 	factories: Factories,
@ -162,35 +237,48 @@ impl State {
 		Ok(state)
 	}

-	/// Create a recoverable snaphot of this state
+	/// Create a recoverable snaphot of this state.
 	pub fn snapshot(&mut self) {
 		self.snapshots.borrow_mut().push(HashMap::new());
 	}

-	/// Merge last snapshot with previous
-	pub fn clear_snapshot(&mut self) {
+	/// Merge last snapshot with previous.
+	pub fn discard_snapshot(&mut self) {
 		// merge with previous snapshot
 		let last = self.snapshots.borrow_mut().pop();
 		if let Some(mut snapshot) = last {
 			if let Some(ref mut prev) = self.snapshots.borrow_mut().last_mut() {
-				for (k, v) in snapshot.drain() {
-					prev.entry(k).or_insert(v);
+				if prev.is_empty() {
+					**prev = snapshot;
+				} else {
+					for (k, v) in snapshot.drain() {
+						prev.entry(k).or_insert(v);
+					}
 				}
 			}
 		}
 	}

-	/// Revert to snapshot
-	pub fn revert_snapshot(&mut self) {
+	/// Revert to the last snapshot and discard it.
+	pub fn revert_to_snapshot(&mut self) {
 		if let Some(mut snapshot) = self.snapshots.borrow_mut().pop() {
 			for (k, v) in snapshot.drain() {
 				match v {
 					Some(v) => {
-						self.cache.borrow_mut().insert(k, v);
+						match self.cache.borrow_mut().entry(k) {
+							Entry::Occupied(mut e) => {
+								// Merge snapshotted changes back into the main account
+								// storage preserving the cache.
+								e.get_mut().overwrite_with(v);
+							},
+							Entry::Vacant(e) => {
+								e.insert(v);
+							}
+						}
 					},
 					None => {
 						match self.cache.borrow_mut().entry(k) {
-							::std::collections::hash_map::Entry::Occupied(e) => {
+							Entry::Occupied(e) => {
 								if e.get().is_dirty() {
 									e.remove();
 								}
@ -204,10 +292,17 @@ impl State {
 	}

 	fn insert_cache(&self, address: &Address, account: AccountEntry) {
-		if let Some(ref mut snapshot) = self.snapshots.borrow_mut().last_mut() {
-			if !snapshot.contains_key(address) {
-				snapshot.insert(address.clone(), self.cache.borrow_mut().insert(address.clone(), account));
-				return;
+		// Dirty account which is not in the cache means this is a new account.
+		// It goes directly into the snapshot as there's nothing to rever to.
+		//
+		// In all other cases account is read as clean first, and after that made
+		// dirty in and added to the snapshot with `note_cache`.
+		if account.is_dirty() {
+			if let Some(ref mut snapshot) = self.snapshots.borrow_mut().last_mut() {
+				if !snapshot.contains_key(address) {
+					snapshot.insert(address.clone(), self.cache.borrow_mut().insert(address.clone(), account));
+					return;
+				}
 			}
 		}
 		self.cache.borrow_mut().insert(address.clone(), account);
@ -216,14 +311,14 @@ impl State {
 	fn note_cache(&self, address: &Address) {
 		if let Some(ref mut snapshot) = self.snapshots.borrow_mut().last_mut() {
 			if !snapshot.contains_key(address) {
-				snapshot.insert(address.clone(), self.cache.borrow().get(address).map(AccountEntry::clone_for_snapshot));
+				snapshot.insert(address.clone(), self.cache.borrow().get(address).map(AccountEntry::clone_dirty));
 			}
 		}
 	}

 	/// Destroy the current object and return root and database.
 	pub fn drop(mut self) -> (H256, StateDB) {
-		self.commit_cache();
+		self.propagate_to_global_cache();
 		(self.root, self.db)
 	}

@ -235,12 +330,12 @@ impl State {
 	/// Create a new contract at address `contract`. If there is already an account at the address
 	/// it will have its code reset, ready for `init_code()`.
 	pub fn new_contract(&mut self, contract: &Address, balance: U256) {
-		self.insert_cache(contract, AccountEntry::Cached(Account::new_contract(balance, self.account_start_nonce)));
+		self.insert_cache(contract, AccountEntry::new_dirty(Some(Account::new_contract(balance, self.account_start_nonce))));
 	}

 	/// Remove an existing account.
 	pub fn kill_account(&mut self, account: &Address) {
-		self.insert_cache(account, AccountEntry::Killed);
+		self.insert_cache(account, AccountEntry::new_dirty(None));
 	}

 	/// Determine whether an account exists.
@ -272,8 +367,8 @@ impl State {
 			let local_cache = self.cache.borrow_mut();
 			let mut local_account = None;
 			if let Some(maybe_acc) = local_cache.get(address) {
-				match *maybe_acc {
-					AccountEntry::Cached(ref account) => {
+				match maybe_acc.account {
+					Some(ref account) => {
 						if let Some(value) = account.cached_storage_at(key) {
 							return value;
 						} else {
@ -292,7 +387,7 @@ impl State {
 				return result;
 			}
 			if let Some(ref mut acc) = local_account {
-				if let AccountEntry::Cached(ref account) = **acc {
+				if let Some(ref account) = acc.account {
 					let account_db = self.factories.accountdb.readonly(self.db.as_hashdb(), account.address_hash(address));
 					return account.storage_at(account_db.as_hashdb(), key)
 				} else {
@ -314,10 +409,7 @@ impl State {
 			let account_db = self.factories.accountdb.readonly(self.db.as_hashdb(), a.address_hash(address));
 			a.storage_at(account_db.as_hashdb(), key)
 		});
-		match maybe_acc {
-			Some(account) => self.insert_cache(address, AccountEntry::Cached(account)),
-			None => self.insert_cache(address, AccountEntry::Missing),
-		}
+		self.insert_cache(address, AccountEntry::new_clean(maybe_acc));
 		r
 	}

@ -341,13 +433,17 @@ impl State {
 	/// Add `incr` to the balance of account `a`.
 	pub fn add_balance(&mut self, a: &Address, incr: &U256) {
 		trace!(target: "state", "add_balance({}, {}): {}", a, incr, self.balance(a));
-		self.require(a, false).add_balance(incr);
+		if !incr.is_zero() || !self.exists(a) {
+			self.require(a, false).add_balance(incr);
+		}
 	}

 	/// Subtract `decr` from the balance of account `a`.
 	pub fn sub_balance(&mut self, a: &Address, decr: &U256) {
 		trace!(target: "state", "sub_balance({}, {}): {}", a, decr, self.balance(a));
-		self.require(a, false).sub_balance(decr);
+		if !decr.is_zero() || !self.exists(a) {
+			self.require(a, false).sub_balance(decr);
+		}
 	}

 	/// Subtracts `by` from the balance of `from` and adds it to that of `to`.
@ -363,7 +459,9 @@ impl State {

 	/// Mutate storage of account `a` so that it is `value` for `key`.
 	pub fn set_storage(&mut self, a: &Address, key: H256, value: H256) {
-		self.require(a, false).set_storage(key, value)
+		if self.storage_at(a, &key) != value {
+			self.require(a, false).set_storage(key, value)
+		}
 	}

 	/// Initialise the code of account `a` so that it is `code`.
@ -404,10 +502,9 @@ impl State {
 		accounts: &mut HashMap<Address, AccountEntry>
 	) -> Result<(), Error> {
 		// first, commit the sub trees.
-		// TODO: is this necessary or can we dispense with the `ref mut a` for just `a`?
-		for (address, ref mut a) in accounts.iter_mut() {
-			match a {
-				&mut&mut AccountEntry::Cached(ref mut account) if account.is_dirty() => {
+		for (address, ref mut a) in accounts.iter_mut().filter(|&(_, ref a)| a.is_dirty()) {
+			match a.account {
+				Some(ref mut account) => {
 					db.note_account_bloom(&address);
 					let addr_hash = account.address_hash(address);
 					let mut account_db = factories.accountdb.create(db.as_hashdb_mut(), addr_hash);
@ -420,17 +517,15 @@ impl State {

 		{
 			let mut trie = factories.trie.from_existing(db.as_hashdb_mut(), root).unwrap();
-			for (address, ref mut a) in accounts.iter_mut() {
-				match **a {
-					AccountEntry::Cached(ref mut account) if account.is_dirty() => {
-						account.set_clean();
+			for (address, ref mut a) in accounts.iter_mut().filter(|&(_, ref a)| a.is_dirty()) {
+				a.state = AccountState::Committed;
+				match a.account {
+					Some(ref mut account) => {
 						try!(trie.insert(address, &account.rlp()));
 					},
-					AccountEntry::Killed => {
+					None => {
 						try!(trie.remove(address));
-						**a = AccountEntry::Missing;
 					},
-					_ => {},
 				}
 			}
 		}
@ -438,20 +533,12 @@ impl State {
 		Ok(())
 	}

-	fn commit_cache(&mut self) {
+	/// Propagate local cache into shared canonical state cache.
+	fn propagate_to_global_cache(&mut self) {
 		let mut addresses = self.cache.borrow_mut();
-		for (address, a) in addresses.drain() {
-			match a {
-				AccountEntry::Cached(account) => {
-					if !account.is_dirty() {
-						self.db.cache_account(address, Some(account));
-					}
-				},
-				AccountEntry::Missing => {
-					self.db.cache_account(address, None);
-				},
-				_ => {},
-			}
+		trace!("Committing cache {:?} entries", addresses.len());
+		for (address, a) in addresses.drain().filter(|&(_, ref a)| a.state == AccountState::Committed || a.state == AccountState::CleanFresh) {
+			self.db.add_to_account_cache(address, a.account, a.state == AccountState::Committed);
 		}
 	}

@ -473,7 +560,7 @@ impl State {
 		assert!(self.snapshots.borrow().is_empty());
 		for (add, acc) in accounts.drain().into_iter() {
 			self.db.note_account_bloom(&add);
-			self.cache.borrow_mut().insert(add, AccountEntry::Cached(Account::from_pod(acc)));
+			self.cache.borrow_mut().insert(add, AccountEntry::new_dirty(Some(Account::from_pod(acc))));
 		}
 	}

@ -483,7 +570,7 @@ impl State {
 		// TODO: handle database rather than just the cache.
 		// will need fat db.
 		PodState::from(self.cache.borrow().iter().fold(BTreeMap::new(), |mut m, (add, opt)| {
-			if let AccountEntry::Cached(ref acc) = *opt {
+			if let Some(ref acc) = opt.account {
 				m.insert(add.clone(), PodAccount::from_account(acc));
 			}
 			m
@ -530,7 +617,7 @@ impl State {
 		where F: Fn(Option<&Account>) -> U {
 		// check local cache first
 		if let Some(ref mut maybe_acc) = self.cache.borrow_mut().get_mut(a) {
-			if let AccountEntry::Cached(ref mut account) = **maybe_acc {
+			if let Some(ref mut account) = maybe_acc.account {
 				let accountdb = self.factories.accountdb.readonly(self.db.as_hashdb(), account.address_hash(a));
 				Self::update_account_cache(require, account, accountdb.as_hashdb());
 				return f(Some(account));
@ -562,10 +649,7 @@ impl State {
 					Self::update_account_cache(require, account, accountdb.as_hashdb());
 				}
 				let r = f(maybe_acc.as_ref());
-				match maybe_acc {
-					Some(account) => self.insert_cache(a, AccountEntry::Cached(account)),
-					None => self.insert_cache(a, AccountEntry::Missing),
-				}
+				self.insert_cache(a, AccountEntry::new_clean(maybe_acc));
 				r
 			}
 		}
@ -584,36 +668,38 @@ impl State {
 		let contains_key = self.cache.borrow().contains_key(a);
 		if !contains_key {
 			match self.db.get_cached_account(a) {
-				Some(Some(acc)) => self.insert_cache(a, AccountEntry::Cached(acc)),
-				Some(None) => self.insert_cache(a, AccountEntry::Missing),
+				Some(acc) => self.insert_cache(a, AccountEntry::new_clean_cached(acc)),
 				None => {
 					let maybe_acc = if self.db.check_account_bloom(a) {
 						let db = self.factories.trie.readonly(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR);
 						let maybe_acc = match db.get(a) {
-							Ok(Some(acc)) => AccountEntry::Cached(Account::from_rlp(acc)),
-							Ok(None) => AccountEntry::Missing,
+							Ok(Some(acc)) => AccountEntry::new_clean(Some(Account::from_rlp(acc))),
+							Ok(None) => AccountEntry::new_clean(None),
 							Err(e) => panic!("Potential DB corruption encountered: {}", e),
 						};
 						maybe_acc
 					}
 					else {
-						AccountEntry::Missing
+						AccountEntry::new_clean(None)
 					};
 					self.insert_cache(a, maybe_acc);
 				}
 			}
-		} else {
-			self.note_cache(a);
-		}
-
-		match self.cache.borrow_mut().get_mut(a).unwrap() {
-			&mut AccountEntry::Cached(ref mut acc) => not_default(acc),
-			slot => *slot = AccountEntry::Cached(default()),
+		}
+		self.note_cache(a);
+
+		match &mut self.cache.borrow_mut().get_mut(a).unwrap().account {
+			&mut Some(ref mut acc) => not_default(acc),
+			slot => *slot = Some(default()),
 		}

+		// at this point the account is guaranteed to be in the cache.
 		RefMut::map(self.cache.borrow_mut(), |c| {
-			match c.get_mut(a).unwrap() {
-				&mut AccountEntry::Cached(ref mut account) => {
+			let mut entry = c.get_mut(a).unwrap();
+			// set the dirty flag after changing account data.
+			entry.state = AccountState::Dirty;
+			match entry.account {
+				Some(ref mut account) => {
 					if require_code {
 						let addr_hash = account.address_hash(a);
 						let accountdb = self.factories.accountdb.readonly(self.db.as_hashdb(), addr_hash);
@ -638,7 +724,7 @@ impl Clone for State {
 		let cache = {
 			let mut cache: HashMap<Address, AccountEntry> = HashMap::new();
 			for (key, val) in self.cache.borrow().iter() {
-				if let Some(entry) = val.clone_dirty() {
+				if let Some(entry) = val.clone_if_dirty() {
 					cache.insert(key.clone(), entry);
 				}
 			}
@ -1679,12 +1765,12 @@ fn snapshot_basic() {
 	state.snapshot();
 	state.add_balance(&a, &U256::from(69u64));
 	assert_eq!(state.balance(&a), U256::from(69u64));
-	state.clear_snapshot();
+	state.discard_snapshot();
 	assert_eq!(state.balance(&a), U256::from(69u64));
 	state.snapshot();
 	state.add_balance(&a, &U256::from(1u64));
 	assert_eq!(state.balance(&a), U256::from(70u64));
-	state.revert_snapshot();
+	state.revert_to_snapshot();
 	assert_eq!(state.balance(&a), U256::from(69u64));
 }

@ -1697,9 +1783,9 @@ fn snapshot_nested() {
 	state.snapshot();
 	state.add_balance(&a, &U256::from(69u64));
 	assert_eq!(state.balance(&a), U256::from(69u64));
-	state.clear_snapshot();
+	state.discard_snapshot();
 	assert_eq!(state.balance(&a), U256::from(69u64));
-	state.revert_snapshot();
+	state.revert_to_snapshot();
 	assert_eq!(state.balance(&a), U256::from(0));
 }

--- a/ethcore/src/state_db.rs
+++ b/ethcore/src/state_db.rs
@ -14,56 +14,94 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

+use std::collections::{VecDeque, HashSet};
 use lru_cache::LruCache;
 use util::journaldb::JournalDB;
 use util::hash::{H256};
 use util::hashdb::HashDB;
 use state::Account;
+use header::BlockNumber;
 use util::{Arc, Address, Database, DBTransaction, UtilError, Mutex, Hashable};
 use bloom_journal::{Bloom, BloomJournal};
 use db::COL_ACCOUNT_BLOOM;
 use byteorder::{LittleEndian, ByteOrder};

-const STATE_CACHE_ITEMS: usize = 65536;
+const STATE_CACHE_ITEMS: usize = 256000;
+const STATE_CACHE_BLOCKS: usize = 8;

 pub const ACCOUNT_BLOOM_SPACE: usize = 1048576;
 pub const DEFAULT_ACCOUNT_PRESET: usize = 1000000;

 pub const ACCOUNT_BLOOM_HASHCOUNT_KEY: &'static [u8] = b"account_hash_count";

+/// Shared canonical state cache.
 struct AccountCache {
 	/// DB Account cache. `None` indicates that account is known to be missing.
 	accounts: LruCache<Address, Option<Account>>,
+	/// Information on the modifications in recently committed blocks; specifically which addresses
+	/// changed in which block. Ordered by block number.
+	modifications: VecDeque<BlockChanges>,
+}
+
+/// Buffered account cache item.
+struct CacheQueueItem {
+	/// Account address.
+	address: Address,
+	/// Acccount data or `None` if account does not exist.
+	account: Option<Account>,
+	/// Indicates that the account was modified before being
+	/// added to the cache.
+	modified: bool,
+}
+
+#[derive(Debug)]
+/// Accumulates a list of accounts changed in a block.
+struct BlockChanges {
+	/// Block number.
+	number: BlockNumber,
+	/// Block hash.
+	hash: H256,
+	/// Parent block hash.
+	parent: H256,
+	/// A set of modified account addresses.
+	accounts: HashSet<Address>,
+	/// Block is part of the canonical chain.
+	is_canon: bool,
 }

 /// State database abstraction.
-/// Manages shared global state cache.
+/// Manages shared global state cache which reflects the canonical
+/// state as it is on the disk. All the entries in the cache are clean.
 /// A clone of `StateDB` may be created as canonical or not.
-/// For canonical clones cache changes are accumulated and applied
-/// on commit.
-/// For non-canonical clones cache is cleared on commit.
+/// For canonical clones local cache is accumulated and applied
+/// in `sync_cache`
+/// For non-canonical clones local cache is dropped.
+///
+/// Global cache propagation.
+/// After a `State` object has been committed to the trie it
+/// propagates its local cache into the `StateDB` local cache
+/// using `add_to_account_cache` function.
+/// Then, after the block has been added to the chain the local cache in the
+/// `StateDB` is propagated into the global cache.
 pub struct StateDB {
+	/// Backing database.
 	db: Box<JournalDB>,
+	/// Shared canonical state cache.
 	account_cache: Arc<Mutex<AccountCache>>,
-	cache_overlay: Vec<(Address, Option<Account>)>,
-	is_canon: bool,
+	/// Local dirty cache.
+	local_cache: Vec<CacheQueueItem>,
+	/// Shared account bloom. Does not handle chain reorganizations.
 	account_bloom: Arc<Mutex<Bloom>>,
+	/// Hash of the block on top of which this instance was created or
+	/// `None` if cache is disabled
+	parent_hash: Option<H256>,
+	/// Hash of the committing block or `None` if not committed yet.
+	commit_hash: Option<H256>,
+	/// Number of the committing block or `None` if not committed yet.
+	commit_number: Option<BlockNumber>,
 }

 impl StateDB {
-
-	/// Create a new instance wrapping `JournalDB`
-	pub fn new(db: Box<JournalDB>) -> StateDB {
-		let bloom = Self::load_bloom(db.backing());
-		StateDB {
-			db: db,
-			account_cache: Arc::new(Mutex::new(AccountCache { accounts: LruCache::new(STATE_CACHE_ITEMS) })),
-			cache_overlay: Vec::new(),
-			is_canon: false,
-			account_bloom: Arc::new(Mutex::new(bloom)),
-		}
-	}
-
 	/// Loads accounts bloom from the database
 	/// This bloom is used to handle request for the non-existant account fast
 	pub fn load_bloom(db: &Database) -> Bloom {
@ -91,6 +129,23 @@ impl StateDB {
 		bloom
 	}

+	/// Create a new instance wrapping `JournalDB`
+	pub fn new(db: Box<JournalDB>) -> StateDB {
+		let bloom = Self::load_bloom(db.backing());
+		StateDB {
+			db: db,
+			account_cache: Arc::new(Mutex::new(AccountCache {
+				accounts: LruCache::new(STATE_CACHE_ITEMS),
+				modifications: VecDeque::new(),
+			})),
+			local_cache: Vec::new(),
+			account_bloom: Arc::new(Mutex::new(bloom)),
+			parent_hash: None,
+			commit_hash: None,
+			commit_number: None,
+		}
+	}
+
 	pub fn check_account_bloom(&self, address: &Address) -> bool {
 		trace!(target: "account_bloom", "Check account bloom: {:?}", address);
 		let bloom = self.account_bloom.lock();
@ -125,14 +180,107 @@ impl StateDB {
 			try!(Self::commit_bloom(batch, bloom_lock.drain_journal()));
 		}
 		let records = try!(self.db.commit(batch, now, id, end));
-		if self.is_canon {
-			self.commit_cache();
-		} else {
-			self.clear_cache();
-		}
+		self.commit_hash = Some(id.clone());
+		self.commit_number = Some(now);
 		Ok(records)
 	}

+	/// Propagate local cache into the global cache and synchonize
+	/// the global cache with the best block state.
+	/// This function updates the global cache by removing entries
+	/// that are invalidated by chain reorganization. `sync_cache`
+	/// should be called after the block has been committed and the
+	/// blockchain route has ben calculated.
+	pub fn sync_cache(&mut self, enacted: &[H256], retracted: &[H256], is_best: bool) {
+		trace!("sync_cache id = (#{:?}, {:?}), parent={:?}, best={}", self.commit_number, self.commit_hash, self.parent_hash, is_best);
+		let mut cache = self.account_cache.lock();
+		let mut cache = &mut *cache;
+
+		// Purge changes from re-enacted and retracted blocks.
+		// Filter out commiting block if any.
+		let mut clear = false;
+		for block in enacted.iter().filter(|h| self.commit_hash.as_ref().map_or(true, |p| *h != p)) {
+			clear = clear || {
+				if let Some(ref mut m) = cache.modifications.iter_mut().find(|ref m| &m.hash == block) {
+					trace!("Reverting enacted block {:?}", block);
+					m.is_canon = true;
+					for a in &m.accounts {
+						trace!("Reverting enacted address {:?}", a);
+						cache.accounts.remove(a);
+					}
+					false
+				} else {
+					true
+				}
+			};
+		}
+
+		for block in retracted {
+			clear = clear || {
+				if let Some(ref mut m) = cache.modifications.iter_mut().find(|ref m| &m.hash == block) {
+					trace!("Retracting block {:?}", block);
+					m.is_canon = false;
+					for a in &m.accounts {
+						trace!("Retracted address {:?}", a);
+						cache.accounts.remove(a);
+					}
+					false
+				} else {
+					true
+				}
+			};
+		}
+		if clear {
+			// We don't know anything about the block; clear everything
+			trace!("Wiping cache");
+			cache.accounts.clear();
+			cache.modifications.clear();
+		}
+
+		// Propagate cache only if committing on top of the latest canonical state
+		// blocks are ordered by number and only one block with a given number is marked as canonical
+		// (contributed to canonical state cache)
+		if let (Some(ref number), Some(ref hash), Some(ref parent)) = (self.commit_number, self.commit_hash, self.parent_hash) {
+			if cache.modifications.len() == STATE_CACHE_BLOCKS {
+				cache.modifications.pop_back();
+			}
+			let mut modifications = HashSet::new();
+			trace!("committing {} cache entries", self.local_cache.len());
+			for account in self.local_cache.drain(..) {
+				if account.modified {
+					modifications.insert(account.address.clone());
+				}
+				if is_best {
+					if let Some(&mut Some(ref mut existing)) = cache.accounts.get_mut(&account.address) {
+						if let Some(new) = account.account {
+							if account.modified {
+								existing.overwrite_with(new);
+							}
+							continue;
+						}
+					}
+					cache.accounts.insert(account.address, account.account);
+				}
+			}
+
+			// Save modified accounts. These are ordered by the block number.
+			let block_changes = BlockChanges {
+				accounts: modifications,
+				number: *number,
+				hash: hash.clone(),
+				is_canon: is_best,
+				parent: parent.clone(),
+			};
+			let insert_at = cache.modifications.iter().enumerate().find(|&(_, ref m)| m.number < *number).map(|(i, _)| i);
+			trace!("inserting modifications at {:?}", insert_at);
+			if let Some(insert_at) = insert_at {
+				cache.modifications.insert(insert_at, block_changes);
+			} else {
+				cache.modifications.push_back(block_changes);
+			}
+		}
+	}
+
 	/// Returns an interface to HashDB.
 	pub fn as_hashdb(&self) -> &HashDB {
 		self.db.as_hashdb()
@ -148,20 +296,24 @@ impl StateDB {
 		StateDB {
 			db: self.db.boxed_clone(),
 			account_cache: self.account_cache.clone(),
-			cache_overlay: Vec::new(),
-			is_canon: false,
+			local_cache: Vec::new(),
 			account_bloom: self.account_bloom.clone(),
+			parent_hash: None,
+			commit_hash: None,
+			commit_number: None,
 		}
 	}

 	/// Clone the database for a canonical state.
-	pub fn boxed_clone_canon(&self) -> StateDB {
+	pub fn boxed_clone_canon(&self, parent: &H256) -> StateDB {
 		StateDB {
 			db: self.db.boxed_clone(),
 			account_cache: self.account_cache.clone(),
-			cache_overlay: Vec::new(),
-			is_canon: true,
+			local_cache: Vec::new(),
 			account_bloom: self.account_bloom.clone(),
+			parent_hash: Some(parent.clone()),
+			commit_hash: None,
+			commit_number: None,
 		}
 	}

@ -180,53 +332,149 @@ impl StateDB {
 		&*self.db
 	}

-	/// Enqueue cache change.
-	pub fn cache_account(&mut self, addr: Address, data: Option<Account>) {
-		self.cache_overlay.push((addr, data));
-	}
-
-	/// Apply pending cache changes.
-	fn commit_cache(&mut self) {
-		let mut cache = self.account_cache.lock();
-		for (address, account) in self.cache_overlay.drain(..) {
-			if let Some(&mut Some(ref mut existing)) = cache.accounts.get_mut(&address) {
-				if let Some(new) = account {
-					existing.merge_with(new);
-					continue;
-				}
-			}
-			cache.accounts.insert(address, account);
-		}
-	}
-
-	/// Clear the cache.
-	pub fn clear_cache(&mut self) {
-		self.cache_overlay.clear();
-		let mut cache = self.account_cache.lock();
-		cache.accounts.clear();
+	/// Add a local cache entry.
+	/// The entry will be propagated to the global cache in `sync_cache`.
+	/// `modified` indicates that the entry was changed since being read from disk or global cache.
+	/// `data` can be set to an existing (`Some`), or non-existing account (`None`).
+	pub fn add_to_account_cache(&mut self, addr: Address, data: Option<Account>, modified: bool) {
+		self.local_cache.push(CacheQueueItem {
+			address: addr,
+			account: data,
+			modified: modified,
+		})
 	}

 	/// Get basic copy of the cached account. Does not include storage.
-	/// Returns 'None' if the state is non-canonical and cache is disabled
-	/// or if the account is not cached.
+	/// Returns 'None' if cache is disabled or if the account is not cached.
 	pub fn get_cached_account(&self, addr: &Address) -> Option<Option<Account>> {
-		if !self.is_canon {
+		let mut cache = self.account_cache.lock();
+		if !Self::is_allowed(addr, &self.parent_hash, &cache.modifications) {
 			return None;
 		}
-		let mut cache = self.account_cache.lock();
 		cache.accounts.get_mut(&addr).map(|a| a.as_ref().map(|a| a.clone_basic()))
 	}

 	/// Get value from a cached account.
-	/// Returns 'None' if the state is non-canonical and cache is disabled
-	/// or if the account is not cached.
+	/// Returns 'None' if cache is disabled or if the account is not cached.
 	pub fn get_cached<F, U>(&self, a: &Address, f: F) -> Option<U>
 		where F: FnOnce(Option<&mut Account>) -> U {
-		if !self.is_canon {
+		let mut cache = self.account_cache.lock();
+		if !Self::is_allowed(a, &self.parent_hash, &cache.modifications) {
 			return None;
 		}
-		let mut cache = self.account_cache.lock();
 		cache.accounts.get_mut(a).map(|c| f(c.as_mut()))
 	}
+
+	/// Check if the account can be returned from cache by matching current block parent hash against canonical
+	/// state and filtering out account modified in later blocks.
+	fn is_allowed(addr: &Address, parent_hash: &Option<H256>, modifications: &VecDeque<BlockChanges>) -> bool {
+		let mut parent = match *parent_hash {
+			None => {
+				trace!("Cache lookup skipped for {:?}: no parent hash", addr);
+				return false;
+			}
+			Some(ref parent) => parent,
+		};
+		if modifications.is_empty() {
+			return true;
+		}
+		// Ignore all accounts modified in later blocks
+		// Modifications contains block ordered by the number
+		// We search for our parent in that list first and then for
+		// all its parent until we hit the canonical block,
+		// checking against all the intermediate modifications.
+		let mut iter = modifications.iter();
+		while let Some(ref m) = iter.next() {
+			if &m.hash == parent {
+				if m.is_canon {
+					return true;
+				}
+				parent = &m.parent;
+			}
+			if m.accounts.contains(addr) {
+				trace!("Cache lookup skipped for {:?}: modified in a later block", addr);
+				return false;
+			}
+		}
+		trace!("Cache lookup skipped for {:?}: parent hash is unknown", addr);
+		return false;
+	}
+}
+
+#[cfg(test)]
+mod tests {
+
+use util::{U256, H256, FixedHash, Address, DBTransaction};
+use tests::helpers::*;
+use state::Account;
+use util::log::init_log;
+
+#[test]
+fn state_db_smoke() {
+	init_log();
+
+	let mut state_db_result = get_temp_state_db();
+	let state_db = state_db_result.take();
+	let root_parent = H256::random();
+	let address = Address::random();
+	let h0 = H256::random();
+	let h1a = H256::random();
+	let h1b = H256::random();
+	let h2a = H256::random();
+	let h2b = H256::random();
+	let h3a = H256::random();
+	let h3b = H256::random();
+	let mut batch = DBTransaction::new(state_db.journal_db().backing());
+
+	// blocks  [ 3a(c) 2a(c) 2b 1b 1a(c) 0 ]
+    // balance [ 5     5     4  3  2     2 ]
+	let mut s = state_db.boxed_clone_canon(&root_parent);
+	s.add_to_account_cache(address, Some(Account::new_basic(2.into(), 0.into())), false);
+	s.commit(&mut batch, 0, &h0, None).unwrap();
+	s.sync_cache(&[], &[], true);
+
+	let mut s = state_db.boxed_clone_canon(&h0);
+	s.commit(&mut batch, 1, &h1a, None).unwrap();
+	s.sync_cache(&[], &[], true);
+
+	let mut s = state_db.boxed_clone_canon(&h0);
+	s.add_to_account_cache(address, Some(Account::new_basic(3.into(), 0.into())), true);
+	s.commit(&mut batch, 1, &h1b, None).unwrap();
+	s.sync_cache(&[], &[], false);
+
+	let mut s = state_db.boxed_clone_canon(&h1b);
+	s.add_to_account_cache(address, Some(Account::new_basic(4.into(), 0.into())), true);
+	s.commit(&mut batch, 2, &h2b, None).unwrap();
+	s.sync_cache(&[], &[], false);
+
+	let mut s = state_db.boxed_clone_canon(&h1a);
+	s.add_to_account_cache(address, Some(Account::new_basic(5.into(), 0.into())), true);
+	s.commit(&mut batch, 2, &h2a, None).unwrap();
+	s.sync_cache(&[], &[], true);
+
+	let mut s = state_db.boxed_clone_canon(&h2a);
+	s.commit(&mut batch, 3, &h3a, None).unwrap();
+	s.sync_cache(&[], &[], true);
+
+	let s = state_db.boxed_clone_canon(&h3a);
+	assert_eq!(s.get_cached_account(&address).unwrap().unwrap().balance(), &U256::from(5));
+
+	let s = state_db.boxed_clone_canon(&h1a);
+	assert!(s.get_cached_account(&address).is_none());
+
+	let s = state_db.boxed_clone_canon(&h2b);
+	assert!(s.get_cached_account(&address).is_none());
+
+	let s = state_db.boxed_clone_canon(&h1b);
+	assert!(s.get_cached_account(&address).is_none());
+
+	// reorg to 3b
+	// blocks  [ 3b(c) 3a 2a 2b(c) 1b 1a 0 ]
+	let mut s = state_db.boxed_clone_canon(&h2b);
+	s.commit(&mut batch, 3, &h3b, None).unwrap();
+	s.sync_cache(&[h1b.clone(), h2b.clone(), h3b.clone()], &[h1a.clone(), h2a.clone(), h3a.clone()], true);
+	let s = state_db.boxed_clone_canon(&h3a);
+	assert!(s.get_cached_account(&address).is_none());
+}
 }

--- a/ethcore/src/tests/client.rs
+++ b/ethcore/src/tests/client.rs
@ -57,7 +57,11 @@ fn should_return_registrar() {
 		IoChannel::disconnected(),
 		&db_config
 	).unwrap();
-	assert_eq!(client.additional_params().get("registrar"), Some(&"52dff57a8a1532e6afb3dc07e2af58bb9eb05b3d".to_owned()));
+	let params = client.additional_params();
+	let address = params.get("registrar").unwrap();
+
+	assert_eq!(address.len(), 40);
+	assert!(U256::from_str(address).is_ok());
 }

 #[test]
--- a/ethcore/src/tests/mod.rs
+++ b/ethcore/src/tests/mod.rs
@ -16,4 +16,5 @@

 pub mod helpers;
 mod client;
+#[cfg(feature="ipc")]
 mod rpc;
--- a/ethcore/src/tests/rpc.rs
+++ b/ethcore/src/tests/rpc.rs
@ -19,7 +19,8 @@
 use nanoipc;
 use std::sync::Arc;
 use std::sync::atomic::{Ordering, AtomicBool};
-use client::{Client, BlockChainClient, ClientConfig, RemoteClient, BlockID};
+use client::{Client, BlockChainClient, ClientConfig, BlockID};
+use client::remote::RemoteClient;
 use tests::helpers::*;
 use devtools::*;
 use miner::Miner;
--- a/ethcore/src/trace/db.rs
+++ b/ethcore/src/trace/db.rs
@ -256,16 +256,6 @@ impl<T> TraceDatabase for TraceDB<T> where T: DatabaseExtras {
 			return;
 		}

-		// at first, let's insert new block traces
-		{
-			let mut traces = self.traces.write();
-			// it's important to use overwrite here,
-			// cause this value might be queried by hash later
-			batch.write_with_cache(db::COL_TRACE, &mut *traces, request.block_hash, request.traces, CacheUpdatePolicy::Overwrite);
-			// note_used must be called after locking traces to avoid cache/traces deadlock on garbage collection
-			self.note_used(CacheID::Trace(request.block_hash.clone()));
-		}
-
 		// now let's rebuild the blooms
 		if !request.enacted.is_empty() {
 			let range_start = request.block_number as Number + 1 - request.enacted.len();
@ -276,12 +266,25 @@ impl<T> TraceDatabase for TraceDB<T> where T: DatabaseExtras {
 				// all traces are expected to be found here. That's why `expect` has been used
 				// instead of `filter_map`. If some traces haven't been found, it meens that
 				// traces database is corrupted or incomplete.
-				.map(|block_hash| self.traces(block_hash).expect("Traces database is incomplete."))
-				.map(|block_traces| block_traces.bloom())
+				.map(|block_hash| if block_hash == &request.block_hash {
+					request.traces.bloom()
+				} else {
+					self.traces(block_hash).expect("Traces database is incomplete.").bloom()
+				})
 				.map(blooms::Bloom::from)
 				.map(Into::into)
 				.collect();

+			// insert new block traces into the cache and the database
+			{
+				let mut traces = self.traces.write();
+				// it's important to use overwrite here,
+				// cause this value might be queried by hash later
+				batch.write_with_cache(db::COL_TRACE, &mut *traces, request.block_hash, request.traces, CacheUpdatePolicy::Overwrite);
+				// note_used must be called after locking traces to avoid cache/traces deadlock on garbage collection
+				self.note_used(CacheID::Trace(request.block_hash.clone()));
+			}
+
 			let chain = BloomGroupChain::new(self.bloom_config, self);
 			let trace_blooms = chain.replace(&replaced_range, enacted_blooms);
 			let blooms_to_insert = trace_blooms.into_iter()
--- a/ethcore/src/types/filter.rs
+++ b/ethcore/src/types/filter.rs
@ -22,7 +22,7 @@ use client::BlockID;
 use log_entry::LogEntry;

 /// Blockchain Filter.
-#[derive(Binary)]
+#[derive(Binary, Debug, PartialEq)]
 pub struct Filter {
 	/// Blockchain will be searched from this block.
 	pub from_block: BlockID,
--- a/ethstore/src/dir/disk.rs
+++ b/ethstore/src/dir/disk.rs
@ -76,15 +76,14 @@ impl DiskDirectory {
 			.map(|entry| entry.path())
 			.collect::<Vec<PathBuf>>();

-		let files: Result<Vec<_>, _> = paths.iter()
-			.map(fs::File::open)
-			.collect();
-
-		let files = try!(files);
-
-		files.into_iter()
-			.map(json::KeyFile::load)
-			.zip(paths.into_iter())
+		paths
+			.iter()
+			.map(|p| (
+				fs::File::open(p)
+					.map_err(Error::from)
+					.and_then(|r| json::KeyFile::load(r).map_err(|e| Error::Custom(format!("{:?}", e)))),
+				p
+			))
 			.map(|(file, path)| match file {
 				Ok(file) => Ok((path.clone(), SafeAccount::from_file(
 					file, Some(path.file_name().and_then(|n| n.to_str()).expect("Keys have valid UTF8 names only.").to_owned())
--- a/ipc/codegen/src/lib.rs
+++ b/ipc/codegen/src/lib.rs
@ -56,7 +56,7 @@ pub fn expand(src: &std::path::Path, dst: &std::path::Path) {
 }

 #[cfg(feature = "with-syntex")]
-pub fn register(reg: &mut syntex::Registry) {
+pub fn register_cleaner(reg: &mut syntex::Registry) {
 	use syntax::{ast, fold};

 	#[cfg(feature = "with-syntex")]
@ -66,6 +66,7 @@ pub fn register(reg: &mut syntex::Registry) {
 			fn fold_attribute(&mut self, attr: ast::Attribute) -> Option<ast::Attribute> {
 				match attr.node.value.node {
 					ast::MetaItemKind::List(ref n, _) if n == &"ipc" => { return None; }
+					ast::MetaItemKind::Word(ref n) if n == &"ipc" => { return None; }
 					_ => {}
 				}

@ -80,13 +81,18 @@ pub fn register(reg: &mut syntex::Registry) {
 		fold::Folder::fold_crate(&mut StripAttributeFolder, krate)
 	}

+	reg.add_post_expansion_pass(strip_attributes);
+}
+
+#[cfg(feature = "with-syntex")]
+pub fn register(reg: &mut syntex::Registry) {
 	reg.add_attr("feature(custom_derive)");
 	reg.add_attr("feature(custom_attribute)");

 	reg.add_decorator("ipc", codegen::expand_ipc_implementation);
 	reg.add_decorator("derive_Binary", serialization::expand_serialization_implementation);

-	reg.add_post_expansion_pass(strip_attributes);
+	register_cleaner(reg);
 }

 #[cfg(not(feature = "with-syntex"))]
@ -104,7 +110,34 @@ pub fn register(reg: &mut rustc_plugin::Registry) {
 }

 #[derive(Debug)]
-pub enum Error { InvalidFileName, ExpandFailure }
+pub enum Error { InvalidFileName, ExpandFailure, Io(std::io::Error) }
+
+impl std::convert::From<std::io::Error> for Error {
+	fn from(err: std::io::Error) -> Self {
+		Error::Io(err)
+	}
+}
+
+pub fn derive_ipc_cond(src_path: &str, has_feature: bool) -> Result<(), Error> {
+	if has_feature { derive_ipc(src_path) }
+	else { cleanup_ipc(src_path) }
+}
+
+pub fn cleanup_ipc(src_path: &str) -> Result<(), Error> {
+	use std::env;
+	use std::path::{Path, PathBuf};
+
+	let out_dir = env::var_os("OUT_DIR").unwrap();
+	let file_name = try!(PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned()));
+	let mut registry = syntex::Registry::new();
+	register_cleaner(&mut registry);
+	if let Err(_) = registry.expand("", &Path::new(src_path), &Path::new(&out_dir).join(&file_name))
+	{
+		// will be reported by compiler
+		return Err(Error::ExpandFailure)
+	}
+	Ok(())
+}

 pub fn derive_ipc(src_path: &str) -> Result<(), Error> {
 	use std::env;
@ -113,11 +146,11 @@ pub fn derive_ipc(src_path: &str) -> Result<(), Error> {
 	let out_dir = env::var_os("OUT_DIR").unwrap();
 	let file_name = try!(PathBuf::from(src_path).file_name().ok_or(Error::InvalidFileName).map(|val| val.to_str().unwrap().to_owned()));

+	let final_path = Path::new(&out_dir).join(&file_name);
+
 	let mut intermediate_file_name = file_name.clone();
 	intermediate_file_name.push_str(".rpc.in");
-
 	let intermediate_path = Path::new(&out_dir).join(&intermediate_file_name);
-	let final_path = Path::new(&out_dir).join(&file_name);

 	{
 		let mut registry = syntex::Registry::new();
--- a/ipc/hypervisor/Cargo.toml
+++ b/ipc/hypervisor/Cargo.toml
@ -13,6 +13,7 @@ nanomsg = { git = "https://github.com/ethcore/nanomsg.rs.git" }
 ethcore-ipc-nano = { path = "../nano" }
 semver = "0.2"
 log = "0.3"
+time = "0.1"

 [build-dependencies]
 ethcore-ipc-codegen = { path = "../codegen" }
--- a/ipc/hypervisor/src/lib.rs
+++ b/ipc/hypervisor/src/lib.rs
@ -22,6 +22,7 @@ extern crate ethcore_ipc as ipc;
 extern crate ethcore_ipc_nano as nanoipc;
 extern crate semver;
 #[macro_use] extern crate log;
+extern crate time;

 pub mod service;

@ -187,23 +188,40 @@ impl Hypervisor {
 	}

 	/// Waits for every required module to check in
-	pub fn wait_for_shutdown(&self) {
+	pub fn wait_for_shutdown(&self) -> bool {
+		use time::{PreciseTime, Duration};
+
 		let mut worker = self.ipc_worker.write().unwrap();
+		let start = PreciseTime::now();
 		while !self.modules_shutdown() {
-			worker.poll()
+			worker.poll();
+			if start.to(PreciseTime::now()) > Duration::seconds(30) {
+				warn!("Some modules failed to shutdown gracefully, they will be terminated.");
+				break;
+			}
 		}
+		self.modules_shutdown()
 	}

 	/// Shutdown the ipc and all managed child processes
 	pub fn shutdown(&self) {
 		let mut childs = self.processes.write().unwrap();
-		for (ref mut module, _) in childs.iter_mut() {
+		for (ref module, _) in childs.iter() {
 			trace!(target: "hypervisor", "Stopping process module: {}", module);
 			self.service.send_shutdown(**module);
 		}
 		trace!(target: "hypervisor", "Waiting for shutdown...");
-		self.wait_for_shutdown();
-		trace!(target: "hypervisor", "All modules reported shutdown");
+		if self.wait_for_shutdown() {
+			trace!(target: "hypervisor", "All modules reported shutdown");
+			return;
+		}
+
+		for (ref module, ref mut process) in childs.iter_mut()  {
+			if self.service.is_running(**module) {
+				process.kill().unwrap();
+				trace!("Terminated {}", module);
+			}
+		}
 	}
 }

--- a/ipc/hypervisor/src/service.rs.in
+++ b/ipc/hypervisor/src/service.rs.in
@ -39,7 +39,6 @@ pub struct ModuleState {
 	shutdown: bool,
 }

-
 #[ipc]
 pub trait ControlService {
 	fn shutdown(&self) -> bool;
@ -106,6 +105,10 @@ impl HypervisorService {
 		self.modules.read().unwrap().iter().filter(|&(_, module)| module.started && !module.shutdown).count()
 	}

+	pub fn is_running(&self, id: IpcModuleId) -> bool {
+		self.modules.read().unwrap().get(&id).map(|module| module.started && !module.shutdown).unwrap_or(false)
+	}
+
 	pub fn send_shutdown(&self, module_id: IpcModuleId) {
 		let modules = self.modules.read().unwrap();
 		modules.get(&module_id).map(|module| {
--- a/parity/cli/config.full.toml
+++ b/parity/cli/config.full.toml
@ -67,7 +67,8 @@ usd_per_eth = "auto"
 price_update_period = "hourly"
 gas_floor_target = "4700000"
 gas_cap = "6283184"
-tx_queue_size = 1024
+tx_queue_size = 2048
+tx_queue_gas = "auto"
 tx_gas_limit = "6283184"
 extra_data = "Parity"
 remove_solved = false
--- a/parity/cli/config.toml
+++ b/parity/cli/config.toml
@ -41,6 +41,7 @@ reseal_on_txs = "all"
 reseal_min_period = 4000
 price_update_period = "hourly"
 tx_queue_size = 2048
+tx_queue_gas = "auto"

 [footprint]
 tracing = "on"
--- a/parity/cli/mod.rs
+++ b/parity/cli/mod.rs
@ -193,8 +193,10 @@ usage! {
 			or |c: &Config| otry!(c.mining).gas_cap.clone(),
 		flag_extra_data: Option<String> = None,
 			or |c: &Config| otry!(c.mining).extra_data.clone().map(Some),
-		flag_tx_queue_size: usize = 1024usize,
+		flag_tx_queue_size: usize = 2048usize,
 			or |c: &Config| otry!(c.mining).tx_queue_size.clone(),
+		flag_tx_queue_gas: String = "auto",
+			or |c: &Config| otry!(c.mining).tx_queue_gas.clone(),
 		flag_remove_solved: bool = false,
 			or |c: &Config| otry!(c.mining).remove_solved.clone(),
 		flag_notify_work: Option<String> = None,
@ -348,6 +350,7 @@ struct Mining {
 	gas_cap: Option<String>,
 	extra_data: Option<String>,
 	tx_queue_size: Option<usize>,
+	tx_queue_gas: Option<String>,
 	remove_solved: Option<bool>,
 	notify_work: Option<Vec<String>>,
 }
@ -522,7 +525,8 @@ mod tests {
 			flag_gas_floor_target: "4700000".into(),
 			flag_gas_cap: "6283184".into(),
 			flag_extra_data: Some("Parity".into()),
-			flag_tx_queue_size: 1024usize,
+			flag_tx_queue_size: 2048usize,
+			flag_tx_queue_gas: "auto".into(),
 			flag_remove_solved: false,
 			flag_notify_work: Some("http://localhost:3001".into()),

@ -673,6 +677,7 @@ mod tests {
 				gas_floor_target: None,
 				gas_cap: None,
 				tx_queue_size: Some(2048),
+				tx_queue_gas: Some("auto".into()),
 				tx_gas_limit: None,
 				extra_data: None,
 				remove_solved: None,
--- a/parity/cli/usage.txt
+++ b/parity/cli/usage.txt
@ -44,7 +44,8 @@ Account Options:
                           ACCOUNTS is a comma-delimited list of addresses.
                           Implies --no-signer. (default: {flag_unlock:?})
  --password FILE          Provide a file containing a password for unlocking
-                           an account. (default: {flag_password:?})
+                           an account. Leading and trailing whitespace is trimmed.
+                           (default: {flag_password:?})
  --keys-iterations NUM    Specify the number of iterations to use when
                           deriving key from the password (bigger is more
                           secure) (default: {flag_keys_iterations}).
@ -183,6 +184,10 @@ Sealing/Mining Options:
                           more than 32 characters. (default: {flag_extra_data:?})
  --tx-queue-size LIMIT    Maximum amount of transactions in the queue (waiting
                           to be included in next block) (default: {flag_tx_queue_size}).
+  --tx-queue-gas LIMIT     Maximum amount of total gas for external transactions in
+                           the queue. LIMIT can be either an amount of gas or
+                           'auto' or 'off'. 'auto' sets the limit to be 2x
+                           the current block gas limit. (default: {flag_tx_queue_gas}).
  --remove-solved          Move solved blocks from the work package queue
                           instead of cloning them. This gives a slightly
                           faster import speed, but means that extra solutions
--- a/parity/configuration.rs
+++ b/parity/configuration.rs
@ -30,7 +30,7 @@ use rpc::{IpcConfiguration, HttpConfiguration};
 use ethcore_rpc::NetworkSettings;
 use cache::CacheConfig;
 use helpers::{to_duration, to_mode, to_block_id, to_u256, to_pending_set, to_price, replace_home,
-geth_ipc_path, parity_ipc_path, to_bootnodes, to_addresses, to_address};
+geth_ipc_path, parity_ipc_path, to_bootnodes, to_addresses, to_address, to_gas_limit};
 use params::{ResealPolicy, AccountsConfig, GasPricerConfig, MinerExtras, SpecType};
 use ethcore_logger::Config as LogConfig;
 use dir::Directories;
@ -125,7 +125,7 @@ impl Configuration {
 				ImportFromGethAccounts {
 					to: dirs.keys,
 					testnet: self.args.flag_testnet
-				} 
+				}
 			);
 			Cmd::Account(account_cmd)
 		} else if self.args.cmd_wallet {
@ -348,6 +348,7 @@ impl Configuration {
 				None => U256::max_value(),
 			},
 			tx_queue_size: self.args.flag_tx_queue_size,
+			tx_queue_gas_limit: try!(to_gas_limit(&self.args.flag_tx_queue_gas)),
 			pending_set: try!(to_pending_set(&self.args.flag_relay_set)),
 			reseal_min_period: Duration::from_millis(self.args.flag_reseal_min_period),
 			work_queue_size: self.args.flag_work_queue_size,
--- a/parity/helpers.rs
+++ b/parity/helpers.rs
@ -22,7 +22,7 @@ use std::fs::File;
 use util::{clean_0x, U256, Uint, Address, path, CompactionProfile};
 use util::journaldb::Algorithm;
 use ethcore::client::{Mode, BlockID, VMType, DatabaseCompactionProfile, ClientConfig};
-use ethcore::miner::PendingSet;
+use ethcore::miner::{PendingSet, GasLimit};
 use cache::CacheConfig;
 use dir::DatabaseDirectories;
 use upgrade::upgrade;
@ -93,6 +93,14 @@ pub fn to_pending_set(s: &str) -> Result<PendingSet, String> {
 	}
 }

+pub fn to_gas_limit(s: &str) -> Result<GasLimit, String> {
+	match s {
+		"auto" => Ok(GasLimit::Auto),
+		"off" => Ok(GasLimit::None),
+		other => Ok(GasLimit::Fixed(try!(to_u256(other)))),
+	}
+}
+
 pub fn to_address(s: Option<String>) -> Result<Address, String> {
 	match s {
 		Some(ref a) => clean_0x(a).parse().map_err(|_| format!("Invalid address: {:?}", a)),
@ -273,9 +281,10 @@ pub fn password_prompt() -> Result<String, String> {
 pub fn password_from_file<P>(path: P) -> Result<String, String> where P: AsRef<Path> {
 	let mut file = try!(File::open(path).map_err(|_| "Unable to open password file."));
 	let mut file_content = String::new();
-	try!(file.read_to_string(&mut file_content).map_err(|_| "Unable to read password file."));
-	// remove eof
-	Ok((&file_content[..file_content.len() - 1]).to_owned())
+	match file.read_to_string(&mut file_content) {
+		Ok(_) => Ok(file_content.trim().into()),
+		Err(_) => Err("Unable to read password file.".into()),
+	}
 }

 /// Reads passwords from files. Treats each line as a separate password.
@ -294,10 +303,13 @@ pub fn passwords_from_files(files: Vec<String>) -> Result<Vec<String>, String> {
 #[cfg(test)]
 mod tests {
 	use std::time::Duration;
+	use std::fs::File;
+	use std::io::Write;
+	use devtools::RandomTempPath;
 	use util::{U256};
 	use ethcore::client::{Mode, BlockID};
 	use ethcore::miner::PendingSet;
-	use super::{to_duration, to_mode, to_block_id, to_u256, to_pending_set, to_address, to_addresses, to_price, geth_ipc_path, to_bootnodes};
+	use super::{to_duration, to_mode, to_block_id, to_u256, to_pending_set, to_address, to_addresses, to_price, geth_ipc_path, to_bootnodes, password_from_file};

 	#[test]
 	fn test_to_duration() {
@ -380,6 +392,14 @@ mod tests {
 		);
 	}

+	#[test]
+	fn test_password() {
+		let path = RandomTempPath::new();
+		let mut file = File::create(path.as_path()).unwrap();
+		file.write_all(b"a bc ").unwrap();
+		assert_eq!(password_from_file(path).unwrap().as_bytes(), b"a bc");
+	}
+
 	#[test]
 	#[cfg_attr(feature = "dev", allow(float_cmp))]
 	fn test_to_price() {
--- a/parity/main.rs
+++ b/parity/main.rs
@ -196,6 +196,9 @@ fn sync_main() -> bool {
 }

 fn main() {
+	// Always print backtrace on panic.
+	::std::env::set_var("RUST_BACKTRACE", "1");
+	
 	if sync_main() {
 		return;
 	}
--- a/parity/modules.rs
+++ b/parity/modules.rs
@ -68,8 +68,9 @@ pub type SyncModules = (Arc<SyncProvider>, Arc<ManageNetwork>, Arc<ChainNotify>)

 #[cfg(feature="ipc")]
 mod ipc_deps {
-	pub use ethsync::{SyncClient, NetworkManagerClient, ServiceConfiguration};
-	pub use ethcore::client::ChainNotifyClient;
+	pub use ethsync::remote::{SyncClient, NetworkManagerClient};
+	pub use ethsync::ServiceConfiguration;
+	pub use ethcore::client::remote::ChainNotifyClient;
 	pub use hypervisor::{SYNC_MODULE_ID, BootArgs, HYPERVISOR_IPC_URL};
 	pub use nanoipc::{GuardedSocket, NanoSocket, generic_client, fast_client};
 	pub use ipc::IpcSocket;
--- a/parity/params.rs
+++ b/parity/params.rs
@ -206,7 +206,7 @@ impl Default for MinerExtras {
 			extra_data: version_data(),
 			gas_floor_target: U256::from(4_700_000),
 			gas_ceil_target: U256::from(6_283_184),
-			transactions_limit: 1024,
+			transactions_limit: 2048,
 		}
 	}
 }
--- a/parity/sync.rs
+++ b/parity/sync.rs
@ -19,8 +19,9 @@
 use std::sync::Arc;
 use std::sync::atomic::AtomicBool;
 use hypervisor::{SYNC_MODULE_ID, HYPERVISOR_IPC_URL, ControlService};
-use ethcore::client::{RemoteClient, ChainNotify};
-use ethcore::snapshot::{RemoteSnapshotService};
+use ethcore::client::ChainNotify;
+use ethcore::client::remote::RemoteClient;
+use ethcore::snapshot::remote::RemoteSnapshotService;
 use ethsync::{SyncProvider, EthSync, ManageNetwork, ServiceConfiguration};
 use modules::service_urls;
 use boot;
--- a/rpc/src/v1/helpers/errors.rs
+++ b/rpc/src/v1/helpers/errors.rs
@ -21,7 +21,7 @@ macro_rules! rpc_unimplemented {
 }

 use std::fmt;
-use ethcore::error::Error as EthcoreError;
+use ethcore::error::{Error as EthcoreError, CallError};
 use ethcore::account_provider::{Error as AccountError};
 use fetch::FetchError;
 use jsonrpc_core::{Error, ErrorCode, Value};
@ -34,6 +34,7 @@ mod codes {
 	pub const NO_NEW_WORK: i64 = -32003;
 	pub const UNKNOWN_ERROR: i64 = -32009;
 	pub const TRANSACTION_ERROR: i64 = -32010;
+	pub const EXECUTION_ERROR: i64 = -32015;
 	pub const ACCOUNT_LOCKED: i64 = -32020;
 	pub const PASSWORD_INVALID: i64 = -32021;
 	pub const ACCOUNT_ERROR: i64 = -32023;
@ -109,6 +110,14 @@ pub fn invalid_params<T: fmt::Debug>(param: &str, details: T) -> Error {
 	}
 }

+pub fn execution<T: fmt::Debug>(data: T) -> Error {
+	Error {
+		code: ErrorCode::ServerError(codes::EXECUTION_ERROR),
+		message: "Transaction execution error.".into(),
+		data: Some(Value::String(format!("{:?}", data))),
+	}
+}
+
 pub fn state_pruned() -> Error {
 	Error {
 		code: ErrorCode::ServerError(codes::UNSUPPORTED_REQUEST),
@ -189,13 +198,13 @@ pub fn from_transaction_error(error: EthcoreError) -> Error {
 			AlreadyImported => "Transaction with the same hash was already imported.".into(),
 			Old => "Transaction nonce is too low. Try incrementing the nonce.".into(),
 			TooCheapToReplace => {
-				"Transaction fee is too low. There is another transaction with same nonce in the queue. Try increasing the fee or incrementing the nonce.".into()
+				"Transaction gas price is too low. There is another transaction with same nonce in the queue. Try increasing the gas price or incrementing the nonce.".into()
 			},
 			LimitReached => {
 				"There are too many transactions in the queue. Your transaction was dropped due to limit. Try increasing the fee.".into()
 			},
 			InsufficientGasPrice { minimal, got } => {
-				format!("Transaction fee is too low. It does not satisfy your node's minimal fee (minimal: {}, got: {}). Try increasing the fee.", minimal, got)
+				format!("Transaction gas price is too low. It does not satisfy your node's minimal gas price (minimal: {}, got: {}). Try increasing the gas price.", minimal, got)
 			},
 			InsufficientBalance { balance, cost } => {
 				format!("Insufficient funds. Account you try to send transaction from does not have enough funds. Required {} and got: {}.", cost, balance)
@ -219,4 +228,10 @@ pub fn from_transaction_error(error: EthcoreError) -> Error {
 	}
 }

-
+pub fn from_call_error(error: CallError) -> Error {
+	match error {
+		CallError::StatePruned => state_pruned(),
+		CallError::Execution(e) => execution(e),
+		CallError::TransactionNotFound => internal("{}, this should not be the case with eth_call, most likely a bug.", CallError::TransactionNotFound),
+	}
+}
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@ -33,7 +33,7 @@ use util::{FromHex, Mutex};
 use rlp::{self, UntrustedRlp, View};
 use ethcore::account_provider::AccountProvider;
 use ethcore::client::{MiningBlockChainClient, BlockID, TransactionID, UncleID};
-use ethcore::header::Header as BlockHeader;
+use ethcore::header::{Header as BlockHeader, BlockNumber as EthBlockNumber};
 use ethcore::block::IsBlock;
 use ethcore::views::*;
 use ethcore::ethereum::Ethash;
@ -198,8 +198,8 @@ impl<C, S: ?Sized, M, EM> EthClient<C, S, M, EM> where
 	}
 }

-pub fn pending_logs<M>(miner: &M, filter: &EthcoreFilter) -> Vec<Log> where M: MinerService {
-	let receipts = miner.pending_receipts();
+pub fn pending_logs<M>(miner: &M, best_block: EthBlockNumber, filter: &EthcoreFilter) -> Vec<Log> where M: MinerService {
+	let receipts = miner.pending_receipts(best_block);

 	let pending_logs = receipts.into_iter()
 		.flat_map(|(hash, r)| r.logs.into_iter().map(|l| (hash.clone(), l)).collect::<Vec<(H256, LogEntry)>>())
@ -426,7 +426,8 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		try!(self.active());
 		let hash: H256 = hash.into();
 		let miner = take_weak!(self.miner);
-		Ok(try!(self.transaction(TransactionID::Hash(hash))).or_else(|| miner.transaction(&hash).map(Into::into)))
+		let client = take_weak!(self.client);
+		Ok(try!(self.transaction(TransactionID::Hash(hash))).or_else(|| miner.transaction(client.chain_info().best_block_number, &hash).map(Into::into)))
 	}

 	fn transaction_by_block_hash_and_index(&self, hash: RpcH256, index: Index) -> Result<Option<Transaction>, Error> {
@ -445,8 +446,9 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 		try!(self.active());

 		let miner = take_weak!(self.miner);
+		let best_block = take_weak!(self.client).chain_info().best_block_number;
 		let hash: H256 = hash.into();
-		match (miner.pending_receipt(&hash), self.options.allow_pending_receipt_query) {
+		match (miner.pending_receipt(best_block, &hash), self.options.allow_pending_receipt_query) {
 			(Some(receipt), true) => Ok(Some(receipt.into())),
 			_ => {
 				let client = take_weak!(self.client);
@ -488,7 +490,8 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			.collect::<Vec<Log>>();

 		if include_pending {
-			let pending = pending_logs(&*take_weak!(self.miner), &filter);
+			let best_block = take_weak!(self.client).chain_info().best_block_number;
+			let pending = pending_logs(&*take_weak!(self.miner), best_block, &filter);
 			logs.extend(pending);
 		}

@ -590,7 +593,10 @@ impl<C, S: ?Sized, M, EM> Eth for EthClient<C, S, M, EM> where
 			num => take_weak!(self.client).call(&signed, num.into(), Default::default()),
 		};

-		Ok(r.map(|e| Bytes(e.output)).unwrap_or(Bytes::new(vec![])))
+		match r {
+			Ok(b) => Ok(Bytes(b.output)),
+			Err(e) => Err(errors::from_call_error(e)),
+		}
 	}

 	fn estimate_gas(&self, request: CallRequest, num: Trailing<BlockNumber>) -> Result<RpcU256, Error> {
--- a/rpc/src/v1/impls/eth_filter.rs
+++ b/rpc/src/v1/impls/eth_filter.rs
@ -81,7 +81,8 @@ impl<C, M> EthFilter for EthFilterClient<C, M>
 		try!(self.active());

 		let mut polls = self.polls.lock();
-		let pending_transactions = take_weak!(self.miner).pending_transactions_hashes();
+		let best_block = take_weak!(self.client).chain_info().best_block_number;
+		let pending_transactions = take_weak!(self.miner).pending_transactions_hashes(best_block);
 		let id = polls.create_poll(PollFilter::PendingTransaction(pending_transactions));
 		Ok(id.into())
 	}
@ -108,7 +109,8 @@ impl<C, M> EthFilter for EthFilterClient<C, M>
 				},
 				PollFilter::PendingTransaction(ref mut previous_hashes) => {
 					// get hashes of pending transactions
-					let current_hashes = take_weak!(self.miner).pending_transactions_hashes();
+					let best_block = take_weak!(self.client).chain_info().best_block_number;
+					let current_hashes = take_weak!(self.miner).pending_transactions_hashes(best_block);

 					let new_hashes =
 					{
@ -149,7 +151,8 @@ impl<C, M> EthFilter for EthFilterClient<C, M>

 					// additionally retrieve pending logs
 					if include_pending {
-						let pending_logs = pending_logs(&*take_weak!(self.miner), &filter);
+						let best_block = take_weak!(self.client).chain_info().best_block_number;
+						let pending_logs = pending_logs(&*take_weak!(self.miner), best_block, &filter);

 						// remove logs about which client was already notified about
 						let new_pending_logs: Vec<_> = pending_logs.iter()
@ -190,7 +193,8 @@ impl<C, M> EthFilter for EthFilterClient<C, M>
 					.collect::<Vec<Log>>();

 				if include_pending {
-					logs.extend(pending_logs(&*take_weak!(self.miner), &filter));
+					let best_block = take_weak!(self.client).chain_info().best_block_number;
+					logs.extend(pending_logs(&*take_weak!(self.miner), best_block, &filter));
 				}

 				let logs = limit_logs(logs, filter.limit);
--- a/rpc/src/v1/tests/eth.rs
+++ b/rpc/src/v1/tests/eth.rs
@ -24,7 +24,7 @@ use ethcore::spec::{Genesis, Spec};
 use ethcore::block::Block;
 use ethcore::views::BlockView;
 use ethcore::ethereum;
-use ethcore::miner::{MinerOptions, GasPricer, MinerService, ExternalMiner, Miner, PendingSet};
+use ethcore::miner::{MinerOptions, GasPricer, MinerService, ExternalMiner, Miner, PendingSet, GasLimit};
 use ethcore::account_provider::AccountProvider;
 use devtools::RandomTempPath;
 use util::Hashable;
@ -58,6 +58,7 @@ fn miner_service(spec: &Spec, accounts: Arc<AccountProvider>) -> Arc<Miner> {
 			reseal_on_own_tx: true,
 			tx_queue_size: 1024,
 			tx_gas_limit: !U256::zero(),
+			tx_queue_gas_limit: GasLimit::None,
 			pending_set: PendingSet::SealingOrElseQueue,
 			reseal_min_period: Duration::from_secs(0),
 			work_queue_size: 50,
--- a/rpc/src/v1/tests/helpers/miner_service.rs
+++ b/rpc/src/v1/tests/helpers/miner_service.rs
@ -21,6 +21,7 @@ use util::standard::*;
 use ethcore::error::{Error, CallError};
 use ethcore::client::{MiningBlockChainClient, Executed, CallAnalytics};
 use ethcore::block::{ClosedBlock, IsBlock};
+use ethcore::header::BlockNumber;
 use ethcore::transaction::SignedTransaction;
 use ethcore::receipt::{Receipt, RichReceipt};
 use ethcore::miner::{MinerService, MinerStatus, TransactionImportResult};
@ -162,7 +163,7 @@ impl MinerService for TestMinerService {
 	}

 	/// Returns hashes of transactions currently in pending
-	fn pending_transactions_hashes(&self) -> Vec<H256> {
+	fn pending_transactions_hashes(&self, _best_block: BlockNumber) -> Vec<H256> {
 		vec![]
 	}

@ -186,7 +187,7 @@ impl MinerService for TestMinerService {
 		Some(f(&open_block.close()))
 	}

-	fn transaction(&self, hash: &H256) -> Option<SignedTransaction> {
+	fn transaction(&self, _best_block: BlockNumber, hash: &H256) -> Option<SignedTransaction> {
 		self.pending_transactions.lock().get(hash).cloned()
 	}

@ -194,13 +195,13 @@ impl MinerService for TestMinerService {
 		self.pending_transactions.lock().values().cloned().collect()
 	}

-	fn pending_transactions(&self) -> Vec<SignedTransaction> {
+	fn pending_transactions(&self, _best_block: BlockNumber) -> Vec<SignedTransaction> {
 		self.pending_transactions.lock().values().cloned().collect()
 	}

-	fn pending_receipt(&self, hash: &H256) -> Option<RichReceipt> {
+	fn pending_receipt(&self, _best_block: BlockNumber, hash: &H256) -> Option<RichReceipt> {
 		// Not much point implementing this since the logic is complex and the only thing it relies on is pending_receipts, which is already tested.
-		self.pending_receipts().get(hash).map(|r|
+		self.pending_receipts(0).get(hash).map(|r|
 			RichReceipt {
 				transaction_hash: Default::default(),
 				transaction_index: Default::default(),
@ -212,7 +213,7 @@ impl MinerService for TestMinerService {
 		)
 	}

-	fn pending_receipts(&self) -> BTreeMap<H256, Receipt> {
+	fn pending_receipts(&self, _best_block: BlockNumber) -> BTreeMap<H256, Receipt> {
 		self.pending_receipts.lock().clone()
 	}

--- a/rpc/src/v1/types/filter.rs
+++ b/rpc/src/v1/types/filter.rs
@ -85,8 +85,14 @@ impl Into<EthFilter> for Filter {
 					VariadicValue::Null => None,
 					VariadicValue::Single(t) => Some(vec![t.into()]),
 					VariadicValue::Multiple(t) => Some(t.into_iter().map(Into::into).collect())
-				}).filter_map(|m| m).collect()).into_iter();
-				vec![iter.next(), iter.next(), iter.next(), iter.next()]
+				}).collect()).into_iter();
+
+				vec![
+					iter.next().unwrap_or(None),
+					iter.next().unwrap_or(None),
+					iter.next().unwrap_or(None),
+					iter.next().unwrap_or(None)
+				]
 			},
 			limit: self.limit,
 		}
@ -121,6 +127,8 @@ mod tests {
 	use util::hash::*;
 	use super::*;
 	use v1::types::BlockNumber;
+	use ethcore::filter::Filter as EthFilter;
+	use ethcore::client::BlockID;

 	#[test]
 	fn topic_deserialization() {
@ -148,4 +156,33 @@ mod tests {
 			limit: None,
 		});
 	}
+
+	#[test]
+	fn filter_conversion() {
+		let filter = Filter {
+			from_block: Some(BlockNumber::Earliest),
+			to_block: Some(BlockNumber::Latest),
+			address: Some(VariadicValue::Multiple(vec![])),
+			topics: Some(vec![
+				VariadicValue::Null,
+				VariadicValue::Single("000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b".into()),
+				VariadicValue::Null,
+			]),
+			limit: None,
+		};
+
+		let eth_filter: EthFilter = filter.into();
+		assert_eq!(eth_filter, EthFilter {
+			from_block: BlockID::Earliest,
+			to_block: BlockID::Latest,
+			address: Some(vec![]),
+			topics: vec![
+				None,
+				Some(vec!["000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b".into()]),
+				None,
+				None,
+			],
+			limit: None,
+		});
+	}
 }
--- a/sync/build.rs
+++ b/sync/build.rs
@ -17,5 +17,5 @@
 extern crate ethcore_ipc_codegen;

 fn main() {
-	ethcore_ipc_codegen::derive_ipc("src/api.rs").unwrap();
+	ethcore_ipc_codegen::derive_ipc_cond("src/api.rs", cfg!(feature="ipc")).unwrap();
 }
--- a/sync/src/blocks.rs
+++ b/sync/src/blocks.rs
@ -184,8 +184,8 @@ impl BlockCollection {
 		{
 			let mut blocks = Vec::new();
 			let mut head = self.head;
-			while head.is_some() {
-				head = self.parents.get(&head.unwrap()).cloned();
+			while let Some(h) = head {
+				head = self.parents.get(&h).cloned();
 				if let Some(head) = head {
 					match self.blocks.get(&head) {
 						Some(block) if block.body.is_some() => {
@ -201,7 +201,7 @@ impl BlockCollection {
 			for block in blocks.drain(..) {
 				let mut block_rlp = RlpStream::new_list(3);
 				block_rlp.append_raw(&block.header, 1);
-				let body = Rlp::new(block.body.as_ref().unwrap()); // incomplete blocks are filtered out in the loop above
+				let body = Rlp::new(block.body.as_ref().expect("blocks contains only full blocks; qed"));
 				block_rlp.append_raw(body.at(0).as_raw(), 1);
 				block_rlp.append_raw(body.at(1).as_raw(), 1);
 				drained.push(block_rlp.out());
--- a/sync/src/chain.rs
+++ b/sync/src/chain.rs
@ -90,7 +90,6 @@
 use util::*;
 use rlp::*;
 use network::*;
-use std::mem::{replace};
 use ethcore::views::{HeaderView, BlockView};
 use ethcore::header::{BlockNumber, Header as BlockHeader};
 use ethcore::client::{BlockChainClient, BlockStatus, BlockID, BlockChainInfo, BlockImportError};
@ -123,6 +122,7 @@ const MAX_ROUND_PARENTS: usize = 32;
 const MAX_NEW_HASHES: usize = 64;
 const MAX_TX_TO_IMPORT: usize = 512;
 const MAX_NEW_BLOCK_AGE: BlockNumber = 20;
+const MAX_TRANSACTION_SIZE: usize = 300*1024;

 const STATUS_PACKET: u8 = 0x00;
 const NEW_BLOCK_HASHES_PACKET: u8 = 0x01;
@ -143,7 +143,7 @@ const GET_SNAPSHOT_DATA_PACKET: u8 = 0x13;
 const SNAPSHOT_DATA_PACKET: u8 = 0x14;

 const HEADERS_TIMEOUT_SEC: f64 = 15f64;
-const BODIES_TIMEOUT_SEC: f64 = 5f64;
+const BODIES_TIMEOUT_SEC: f64 = 10f64;
 const FORK_HEADER_TIMEOUT_SEC: f64 = 3f64;
 const SNAPSHOT_MANIFEST_TIMEOUT_SEC: f64 = 3f64;
 const SNAPSHOT_DATA_TIMEOUT_SEC: f64 = 10f64;
@ -249,8 +249,6 @@ struct PeerInfo {
 	network_id: U256,
 	/// Peer best block hash
 	latest_hash: H256,
-	/// Peer best block number if known
-	latest_number: Option<BlockNumber>,
 	/// Peer total difficulty if known
 	difficulty: Option<U256>,
 	/// Type of data currenty being requested from peer.
@ -395,6 +393,8 @@ impl ChainSync {
 		}
 		self.syncing_difficulty = From::from(0u64);
 		self.state = SyncState::Idle;
+		// Reactivate peers only if some progress has been made
+		// since the last sync round of if starting fresh.
 		self.active_peers = self.peers.keys().cloned().collect();
 	}

@ -406,7 +406,8 @@ impl ChainSync {
 		self.continue_sync(io);
 	}

-	/// Remove peer from active peer set
+	/// Remove peer from active peer set. Peer will be reactivated on the next sync
+	/// round.
 	fn deactivate_peer(&mut self, io: &mut SyncIo, peer_id: PeerId) {
 		trace!(target: "sync", "Deactivating peer {}", peer_id);
 		self.active_peers.remove(&peer_id);
@ -443,7 +444,6 @@ impl ChainSync {
 			network_id: try!(r.val_at(1)),
 			difficulty: Some(try!(r.val_at(2))),
 			latest_hash: try!(r.val_at(3)),
-			latest_number: None,
 			genesis: try!(r.val_at(4)),
 			asking: PeerAsking::Nothing,
 			asking_blocks: Vec::new(),
@ -480,7 +480,11 @@ impl ChainSync {
 		}

 		self.peers.insert(peer_id.clone(), peer);
-		self.active_peers.insert(peer_id.clone());
+		// Don't activate peer immediatelly when searching for common block.
+		// Let the current sync round complete first.
+		if self.state != SyncState::ChainHead {
+			self.active_peers.insert(peer_id.clone());
+		}
 		debug!(target: "sync", "Connected {}:{}", peer_id, io.peer_info(peer_id));
 		if let Some((fork_block, _)) = self.fork_block {
 			self.request_headers_by_number(io, peer_id, fork_block, 1, 0, false, PeerAsking::ForkHeader);
@ -496,7 +500,8 @@ impl ChainSync {
 		let confirmed = match self.peers.get_mut(&peer_id) {
 			Some(ref mut peer) if peer.asking == PeerAsking::ForkHeader => {
 				let item_count = r.item_count();
-				if item_count == 0 || (item_count == 1 && try!(r.at(0)).as_raw().sha3() == self.fork_block.unwrap().1) {
+				if item_count == 0 || (item_count == 1 &&
+						try!(r.at(0)).as_raw().sha3() == self.fork_block.expect("ForkHeader state is only entered when fork_block is some; qed").1) {
 					peer.asking = PeerAsking::Nothing;
 					if item_count == 0 {
 						trace!(target: "sync", "{}: Chain is too short to confirm the block", peer_id);
@ -562,7 +567,7 @@ impl ChainSync {
 				continue;
 			}

-			if self.highest_block == None || number > self.highest_block.unwrap() {
+			if self.highest_block.as_ref().map_or(true,  |n| number > *n) {
 				self.highest_block = Some(number);
 			}
 			let hash = info.hash();
@ -594,9 +599,9 @@ impl ChainSync {
 		}

 		if headers.is_empty() {
-			// Peer does not have any new subchain heads, deactivate it nd try with another
+			// Peer does not have any new subchain heads, deactivate it and try with another.
 			trace!(target: "sync", "{} Disabled for no data", peer_id);
-			io.disable_peer(peer_id);
+			self.deactivate_peer(io, peer_id);
 		}
 		match self.state {
 			SyncState::ChainHead => {
@ -675,9 +680,9 @@ impl ChainSync {
 		}
 		let mut unknown = false;
 		{
-			let peer = self.peers.get_mut(&peer_id).unwrap();
-			peer.latest_hash = header.hash();
-			peer.latest_number = Some(header.number());
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.latest_hash = header.hash();
+			}
 		}
 		if self.last_imported_block > header.number() && self.last_imported_block - header.number() > MAX_NEW_BLOCK_AGE {
 			trace!(target: "sync", "Ignored ancient new block {:?}", h);
@ -770,9 +775,9 @@ impl ChainSync {
 					new_hashes.push(hash.clone());
 					if number > max_height {
 						trace!(target: "sync", "New unknown block hash {:?}", hash);
-						let peer = self.peers.get_mut(&peer_id).unwrap();
-						peer.latest_hash = hash.clone();
-						peer.latest_number = Some(number);
+						if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+							peer.latest_hash = hash.clone();
+						}
 						max_height = number;
 					}
 				},
@ -942,19 +947,22 @@ impl ChainSync {
 			return;
 		}
 		let (peer_latest, peer_difficulty, peer_snapshot_number, peer_snapshot_hash) = {
-			let peer = self.peers.get_mut(&peer_id).unwrap();
-			if peer.asking != PeerAsking::Nothing || !peer.can_sync() {
+			if let Some(ref peer) = self.peers.get_mut(&peer_id) {
+				if peer.asking != PeerAsking::Nothing || !peer.can_sync() {
+					return;
+				}
+				if self.state == SyncState::Waiting {
+					trace!(target: "sync", "Waiting for the block queue");
+					return;
+				}
+				if self.state == SyncState::SnapshotWaiting {
+					trace!(target: "sync", "Waiting for the snapshot restoration");
+					return;
+				}
+				(peer.latest_hash.clone(), peer.difficulty.clone(), peer.snapshot_number.as_ref().cloned(), peer.snapshot_hash.as_ref().cloned())
+			} else {
 				return;
 			}
-			if self.state == SyncState::Waiting {
-				trace!(target: "sync", "Waiting for the block queue");
-				return;
-			}
-			if self.state == SyncState::SnapshotWaiting {
-				trace!(target: "sync", "Waiting for the snapshot restoration");
-				return;
-			}
-			(peer.latest_hash.clone(), peer.difficulty.clone(), peer.snapshot_number.as_ref().cloned(), peer.snapshot_hash.as_ref().cloned())
 		};
 		let chain_info = io.chain().chain_info();
 		let td = chain_info.pending_total_difficulty;
@ -1042,14 +1050,18 @@ impl ChainSync {
 		// check to see if we need to download any block bodies first
 		let needed_bodies = self.blocks.needed_bodies(MAX_BODIES_TO_REQUEST, ignore_others);
 		if !needed_bodies.is_empty() {
-			replace(&mut self.peers.get_mut(&peer_id).unwrap().asking_blocks, needed_bodies.clone());
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.asking_blocks = needed_bodies.clone();
+			}
 			self.request_bodies(io, peer_id, needed_bodies);
 			return;
 		}

 		// find subchain to download
 		if let Some((h, count)) = self.blocks.needed_headers(MAX_HEADERS_TO_REQUEST, ignore_others) {
-			replace(&mut self.peers.get_mut(&peer_id).unwrap().asking_blocks, vec![h.clone()]);
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.asking_blocks = vec![h.clone()];
+			}
 			self.request_headers_by_hash(io, peer_id, &h, count, 0, false, PeerAsking::BlockHeaders);
 		}
 	}
@ -1059,34 +1071,37 @@ impl ChainSync {
 		self.clear_peer_download(peer_id);
 		// find chunk data to download
 		if let Some(hash) = self.snapshot.needed_chunk() {
-			self.peers.get_mut(&peer_id).unwrap().asking_snapshot_data = Some(hash.clone());
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.asking_snapshot_data = Some(hash.clone());
+			}
 			self.request_snapshot_chunk(io, peer_id, &hash);
 		}
 	}

 	/// Clear all blocks/headers marked as being downloaded by a peer.
 	fn clear_peer_download(&mut self, peer_id: PeerId) {
-		let peer = self.peers.get_mut(&peer_id).unwrap();
-		match peer.asking {
-			PeerAsking::BlockHeaders | PeerAsking::Heads => {
-				for b in &peer.asking_blocks {
-					self.blocks.clear_header_download(b);
-				}
-			},
-			PeerAsking::BlockBodies => {
-				for b in &peer.asking_blocks {
-					self.blocks.clear_body_download(b);
-				}
-			},
-			PeerAsking::SnapshotData => {
-				if let Some(hash) = peer.asking_snapshot_data {
-					self.snapshot.clear_chunk_download(&hash);
-				}
-			},
-			_ => (),
+		if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+			match peer.asking {
+				PeerAsking::BlockHeaders | PeerAsking::Heads => {
+					for b in &peer.asking_blocks {
+						self.blocks.clear_header_download(b);
+					}
+				},
+				PeerAsking::BlockBodies => {
+					for b in &peer.asking_blocks {
+						self.blocks.clear_body_download(b);
+					}
+				},
+				PeerAsking::SnapshotData => {
+					if let Some(hash) = peer.asking_snapshot_data {
+						self.snapshot.clear_chunk_download(&hash);
+					}
+				},
+				_ => (),
+			}
+			peer.asking_blocks.clear();
+			peer.asking_snapshot_data = None;
 		}
-		peer.asking_blocks.clear();
-		peer.asking_snapshot_data = None;
 	}

 	fn block_imported(&mut self, hash: &H256, number: BlockNumber, parent: &H256) {
@ -1211,30 +1226,34 @@ impl ChainSync {

 	/// Reset peer status after request is complete.
 	fn reset_peer_asking(&mut self, peer_id: PeerId, asking: PeerAsking) -> bool {
-		let peer = self.peers.get_mut(&peer_id).unwrap();
-		peer.expired = false;
-		if peer.asking != asking {
-			trace!(target:"sync", "Asking {:?} while expected {:?}", peer.asking, asking);
-			peer.asking = PeerAsking::Nothing;
+		if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+			peer.expired = false;
+			if peer.asking != asking {
+				trace!(target:"sync", "Asking {:?} while expected {:?}", peer.asking, asking);
+				peer.asking = PeerAsking::Nothing;
+				false
+			}
+			else {
+				peer.asking = PeerAsking::Nothing;
+				true
+			}
+		} else {
 			false
 		}
-		else {
-			peer.asking = PeerAsking::Nothing;
-			true
-		}
 	}

 	/// Generic request sender
 	fn send_request(&mut self, sync: &mut SyncIo, peer_id: PeerId, asking: PeerAsking,  packet_id: PacketId, packet: Bytes) {
-		let peer = self.peers.get_mut(&peer_id).unwrap();
-		if peer.asking != PeerAsking::Nothing {
-			warn!(target:"sync", "Asking {:?} while requesting {:?}", peer.asking, asking);
-		}
-		peer.asking = asking;
-		peer.ask_time = time::precise_time_s();
-		if let Err(e) = sync.send(peer_id, packet_id, packet) {
-			debug!(target:"sync", "Error sending request: {:?}", e);
-			sync.disable_peer(peer_id);
+		if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+			if peer.asking != PeerAsking::Nothing {
+				warn!(target:"sync", "Asking {:?} while requesting {:?}", peer.asking, asking);
+			}
+			peer.asking = asking;
+			peer.ask_time = time::precise_time_s();
+			if let Err(e) = sync.send(peer_id, packet_id, packet) {
+				debug!(target:"sync", "Error sending request: {:?}", e);
+				sync.disable_peer(peer_id);
+			}
 		}
 	}

@ -1261,7 +1280,12 @@ impl ChainSync {
 		item_count = min(item_count, MAX_TX_TO_IMPORT);
 		let mut transactions = Vec::with_capacity(item_count);
 		for i in 0 .. item_count {
-			let tx = try!(r.at(i)).as_raw().to_vec();
+			let rlp = try!(r.at(i));
+			if rlp.as_raw().len() > MAX_TRANSACTION_SIZE {
+				debug!("Skipped oversized transaction of {} bytes", rlp.as_raw().len());
+				continue;
+			}
+			let tx = rlp.as_raw().to_vec();
 			transactions.push(tx);
 		}
 		io.chain().queue_transactions(transactions);
@ -1604,7 +1628,7 @@ impl ChainSync {
 	/// creates latest block rlp for the given client
 	fn create_latest_block_rlp(chain: &BlockChainClient) -> Bytes {
 		let mut rlp_stream = RlpStream::new_list(2);
-		rlp_stream.append_raw(&chain.block(BlockID::Hash(chain.chain_info().best_block_hash)).unwrap(), 1);
+		rlp_stream.append_raw(&chain.block(BlockID::Hash(chain.chain_info().best_block_hash)).expect("Best block always exists"), 1);
 		rlp_stream.append(&chain.chain_info().total_difficulty);
 		rlp_stream.out()
 	}
@ -1618,25 +1642,23 @@ impl ChainSync {
 	}

 	/// returns peer ids that have less blocks than our chain
-	fn get_lagging_peers(&mut self, chain_info: &BlockChainInfo, io: &SyncIo) -> Vec<(PeerId, BlockNumber)> {
+	fn get_lagging_peers(&mut self, chain_info: &BlockChainInfo, io: &SyncIo) -> Vec<PeerId> {
 		let latest_hash = chain_info.best_block_hash;
-		let latest_number = chain_info.best_block_number;
 		self.peers.iter_mut().filter_map(|(&id, ref mut peer_info)|
 			match io.chain().block_status(BlockID::Hash(peer_info.latest_hash.clone())) {
 				BlockStatus::InChain => {
-					if peer_info.latest_number.is_none() {
-						peer_info.latest_number = Some(HeaderView::new(&io.chain().block_header(BlockID::Hash(peer_info.latest_hash.clone())).unwrap()).number());
+					if peer_info.latest_hash != latest_hash {
+						Some(id)
+					} else {
+						None
 					}
-					if peer_info.latest_hash != latest_hash && latest_number > peer_info.latest_number.unwrap() {
-						Some((id, peer_info.latest_number.unwrap()))
-					} else { None }
 				},
 				_ => None
 			})
 			.collect::<Vec<_>>()
 	}

-	fn select_random_lagging_peers(&mut self, peers: &[(PeerId, BlockNumber)]) -> Vec<(PeerId, BlockNumber)> {
+	fn select_random_lagging_peers(&mut self, peers: &[PeerId]) -> Vec<PeerId> {
 		use rand::Rng;
 		// take sqrt(x) peers
 		let mut peers = peers.to_vec();
@ -1649,46 +1671,42 @@ impl ChainSync {
 	}

 	/// propagates latest block to lagging peers
-	fn propagate_blocks(&mut self, chain_info: &BlockChainInfo, io: &mut SyncIo, sealed: &[H256], peers: &[(PeerId, BlockNumber)]) -> usize {
+	fn propagate_blocks(&mut self, chain_info: &BlockChainInfo, io: &mut SyncIo, sealed: &[H256], peers: &[PeerId]) -> usize {
 		trace!(target: "sync", "Sending NewBlocks to {:?}", peers);
 		let mut sent = 0;
-		for &(peer_id, _) in peers {
+		for peer_id in peers {
 			if sealed.is_empty() {
 				let rlp =  ChainSync::create_latest_block_rlp(io.chain());
-				self.send_packet(io, peer_id, NEW_BLOCK_PACKET, rlp);
+				self.send_packet(io, *peer_id, NEW_BLOCK_PACKET, rlp);
 			} else {
 				for h in sealed {
 					let rlp =  ChainSync::create_new_block_rlp(io.chain(), h);
-					self.send_packet(io, peer_id, NEW_BLOCK_PACKET, rlp);
+					self.send_packet(io, *peer_id, NEW_BLOCK_PACKET, rlp);
 				}
 			}
-			self.peers.get_mut(&peer_id).unwrap().latest_hash = chain_info.best_block_hash.clone();
-			self.peers.get_mut(&peer_id).unwrap().latest_number = Some(chain_info.best_block_number);
+			if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+				peer.latest_hash = chain_info.best_block_hash.clone();
+			}
 			sent += 1;
 		}
 		sent
 	}

 	/// propagates new known hashes to all peers
-	fn propagate_new_hashes(&mut self, chain_info: &BlockChainInfo, io: &mut SyncIo, peers: &[(PeerId, BlockNumber)]) -> usize {
+	fn propagate_new_hashes(&mut self, chain_info: &BlockChainInfo, io: &mut SyncIo, peers: &[PeerId]) -> usize {
 		trace!(target: "sync", "Sending NewHashes to {:?}", peers);
 		let mut sent = 0;
-		let last_parent = HeaderView::new(&io.chain().block_header(BlockID::Hash(chain_info.best_block_hash.clone())).unwrap()).parent_hash();
-		for &(peer_id, peer_number) in peers {
-			let peer_best = if chain_info.best_block_number - peer_number > MAX_PEER_LAG_PROPAGATION as BlockNumber {
-				// If we think peer is too far behind just send one latest hash
-				last_parent.clone()
-			} else {
-				self.peers.get(&peer_id).unwrap().latest_hash.clone()
-			};
-			sent += match ChainSync::create_new_hashes_rlp(io.chain(), &peer_best, &chain_info.best_block_hash) {
+		let last_parent = HeaderView::new(&io.chain().block_header(BlockID::Hash(chain_info.best_block_hash.clone()))
+			.expect("Best block always exists")).parent_hash();
+		for peer_id in peers {
+			sent += match ChainSync::create_new_hashes_rlp(io.chain(), &last_parent, &chain_info.best_block_hash) {
 				Some(rlp) => {
 					{
-						let peer = self.peers.get_mut(&peer_id).unwrap();
-						peer.latest_hash = chain_info.best_block_hash.clone();
-						peer.latest_number = Some(chain_info.best_block_number);
+						if let Some(ref mut peer) = self.peers.get_mut(&peer_id) {
+							peer.latest_hash = chain_info.best_block_hash.clone();
+						}
 					}
-					self.send_packet(io, peer_id, NEW_BLOCK_HASHES_PACKET, rlp);
+					self.send_packet(io, *peer_id, NEW_BLOCK_HASHES_PACKET, rlp);
 					1
 				},
 				None => 0
@ -2001,7 +2019,6 @@ mod tests {
 				genesis: H256::zero(),
 				network_id: U256::zero(),
 				latest_hash: peer_latest_hash,
-				latest_number: None,
 				difficulty: None,
 				asking: PeerAsking::Nothing,
 				asking_blocks: Vec::new(),
--- a/sync/src/lib.rs
+++ b/sync/src/lib.rs
@ -64,3 +64,9 @@ pub use api::{EthSync, SyncProvider, SyncClient, NetworkManagerClient, ManageNet
 	ServiceConfiguration, NetworkConfiguration};
 pub use chain::{SyncStatus, SyncState};
 pub use network::{is_valid_node_url, NonReservedPeerMode, NetworkError};
+
+/// IPC interfaces
+#[cfg(feature="ipc")]
+pub mod remote {
+	pub use api::{SyncClient, NetworkManagerClient};
+}
--- a/sync/src/tests/chain.rs
+++ b/sync/src/tests/chain.rs
@ -95,6 +95,27 @@ fn forked() {
 	assert_eq!(&*net.peer(2).chain.numbers.read(), &peer1_chain);
 }

+#[test]
+fn forked_with_misbehaving_peer() {
+	::env_logger::init().ok();
+	let mut net = TestNet::new(3);
+	// peer 0 is on a totally different chain with higher total difficulty
+	net.peer_mut(0).chain = TestBlockChainClient::new_with_extra_data(b"fork".to_vec());
+	net.peer_mut(0).chain.add_blocks(500, EachBlockWith::Nothing);
+	net.peer_mut(1).chain.add_blocks(100, EachBlockWith::Nothing);
+	net.peer_mut(2).chain.add_blocks(100, EachBlockWith::Nothing);
+
+	net.peer_mut(1).chain.add_blocks(100, EachBlockWith::Nothing);
+	net.peer_mut(2).chain.add_blocks(200, EachBlockWith::Uncle);
+	// peer 1 should sync to peer 2, others should not change
+	let peer0_chain = net.peer(0).chain.numbers.read().clone();
+	let peer2_chain = net.peer(2).chain.numbers.read().clone();
+	net.sync();
+	assert_eq!(&*net.peer(0).chain.numbers.read(), &peer0_chain);
+	assert_eq!(&*net.peer(1).chain.numbers.read(), &peer2_chain);
+	assert_eq!(&*net.peer(2).chain.numbers.read(), &peer2_chain);
+}
+
 #[test]
 fn net_hard_fork() {
 	::env_logger::init().ok();
@ -116,11 +137,12 @@ fn net_hard_fork() {

 #[test]
 fn restart() {
+	::env_logger::init().ok();
 	let mut net = TestNet::new(3);
 	net.peer_mut(1).chain.add_blocks(1000, EachBlockWith::Uncle);
 	net.peer_mut(2).chain.add_blocks(1000, EachBlockWith::Uncle);

-	net.sync_steps(8);
+	net.sync();

 	// make sure that sync has actually happened
 	assert!(net.peer(0).chain.chain_info().best_block_number > 100);
--- a/sync/src/tests/helpers.rs
+++ b/sync/src/tests/helpers.rs
@ -29,6 +29,7 @@ pub struct TestIo<'p> {
 	pub snapshot_service: &'p TestSnapshotService,
 	pub queue: &'p mut VecDeque<TestPacket>,
 	pub sender: Option<PeerId>,
+	pub to_disconnect: HashSet<PeerId>,
 }

 impl<'p> TestIo<'p> {
@ -37,16 +38,19 @@ impl<'p> TestIo<'p> {
 			chain: chain,
 			snapshot_service: ss,
 			queue: queue,
-			sender: sender
+			sender: sender,
+			to_disconnect: HashSet::new(),
 		}
 	}
 }

 impl<'p> SyncIo for TestIo<'p> {
-	fn disable_peer(&mut self, _peer_id: PeerId) {
+	fn disable_peer(&mut self, peer_id: PeerId) {
+		self.disconnect_peer(peer_id);
 	}

-	fn disconnect_peer(&mut self, _peer_id: PeerId) {
+	fn disconnect_peer(&mut self, peer_id: PeerId) {
+		self.to_disconnect.insert(peer_id);
 	}

 	fn is_expired(&self) -> bool {
@ -150,13 +154,30 @@ impl TestNet {
 	pub fn sync_step(&mut self) {
 		for peer in 0..self.peers.len() {
 			if let Some(packet) = self.peers[peer].queue.pop_front() {
-				let mut p = self.peers.get_mut(packet.recipient).unwrap();
-				trace!("--- {} -> {} ---", peer, packet.recipient);
-				ChainSync::dispatch_packet(&p.sync, &mut TestIo::new(&mut p.chain, &p.snapshot_service, &mut p.queue, Some(peer as PeerId)), peer as PeerId, packet.packet_id, &packet.data);
-				trace!("----------------");
+				let disconnecting = {
+					let mut p = self.peers.get_mut(packet.recipient).unwrap();
+					trace!("--- {} -> {} ---", peer, packet.recipient);
+					let to_disconnect = {
+						let mut io = TestIo::new(&mut p.chain, &p.snapshot_service, &mut p.queue, Some(peer as PeerId));
+						ChainSync::dispatch_packet(&p.sync, &mut io, peer as PeerId, packet.packet_id, &packet.data);
+						io.to_disconnect
+					};
+					for d in &to_disconnect {
+						// notify this that disconnecting peers are disconnecting
+						let mut io = TestIo::new(&mut p.chain, &p.snapshot_service, &mut p.queue, Some(*d));
+						p.sync.write().on_peer_aborting(&mut io, *d);
+					}
+					to_disconnect
+				};
+				for d in &disconnecting {
+					// notify other peers that this peer is disconnecting
+					let mut p = self.peers.get_mut(*d).unwrap();
+					let mut io = TestIo::new(&mut p.chain, &p.snapshot_service, &mut p.queue, Some(peer as PeerId));
+					p.sync.write().on_peer_aborting(&mut io, peer as PeerId);
+				}
 			}
-			let mut p = self.peers.get_mut(peer).unwrap();
-			p.sync.write().maintain_sync(&mut TestIo::new(&mut p.chain, &p.snapshot_service, &mut p.queue, None));
+
+			self.sync_step_peer(peer);
 		}
 	}

--- a/util/bigint/Cargo.toml
+++ b/util/bigint/Cargo.toml
@ -4,7 +4,7 @@ homepage = "http://ethcore.io"
 repository = "https://github.com/ethcore/parity"
 license = "GPL-3.0"
 name = "ethcore-bigint"
-version = "0.1.0"
+version = "0.1.1"
 authors = ["Ethcore <admin@ethcore.io>"]
 build = "build.rs"

--- a/util/io/src/lib.rs
+++ b/util/io/src/lib.rs
@ -68,6 +68,8 @@ mod panics;
 use mio::{EventLoop, Token};
 use std::fmt;

+pub use worker::LOCAL_STACK_SIZE;
+
 #[derive(Debug)]
 /// IO Error
 pub enum IoError {
--- a/util/io/src/worker.rs
+++ b/util/io/src/worker.rs
@ -22,9 +22,19 @@ use crossbeam::sync::chase_lev;
 use service::{HandlerId, IoChannel, IoContext};
 use IoHandler;
 use panics::*;
+use std::cell::Cell;

 use std::sync::{Condvar as SCondvar, Mutex as SMutex};

+const STACK_SIZE: usize = 16*1024*1024;
+
+thread_local! {
+	/// Stack size
+	/// Should be modified if it is changed in Rust since it is no way
+	/// to know or get it
+	pub static LOCAL_STACK_SIZE: Cell<usize> = Cell::new(::std::env::var("RUST_MIN_STACK").ok().and_then(|s| s.parse().ok()).unwrap_or(2 * 1024 * 1024));
+}
+
 pub enum WorkType<Message> {
 	Readable,
 	Writable,
@ -66,8 +76,9 @@ impl Worker {
 			deleting: deleting.clone(),
 			wait_mutex: wait_mutex.clone(),
 		};
-		worker.thread = Some(thread::Builder::new().name(format!("IO Worker #{}", index)).spawn(
+		worker.thread = Some(thread::Builder::new().stack_size(STACK_SIZE).name(format!("IO Worker #{}", index)).spawn(
 			move || {
+				LOCAL_STACK_SIZE.with(|val| val.set(STACK_SIZE));
 				panic_handler.catch_panic(move || {
 					Worker::work_loop(stealer, channel.clone(), wait, wait_mutex.clone(), deleting)
 				}).unwrap()
--- a/util/network/src/host.rs
+++ b/util/network/src/host.rs
@ -591,7 +591,8 @@ impl Host {
 	}

 	fn handshake_count(&self) -> usize {
-		self.sessions.read().count() - self.session_count()
+		// session_count < total_count is possible because of the data race.
+		self.sessions.read().count().saturating_sub(self.session_count())
 	}

 	fn keep_alive(&self, io: &IoContext<NetworkIoMessage>) {