Limit the number of transactions in pending set (#8777)

* Unordered iterator.

* Use unordered and limited set if full not required.

* Split timeout work into smaller timers.

* Avoid collecting all pending transactions when mining

* Remove println.

* Use priority ordering in eth-filter.

* Fix ethcore-miner tests and tx propagation.

* Review grumbles addressed.

* Add test for unordered not populating the cache.

* Fix ethcore tests.

* Fix light tests.

* Fix ethcore-sync tests.

* Fix RPC tests.

ethcore/light/src/net/mod.rs

@@ -72,6 +72,9 @@ const PROPAGATE_TIMEOUT_INTERVAL: Duration = Duration::from_secs(5);
 const RECALCULATE_COSTS_TIMEOUT: TimerToken = 3;
 const RECALCULATE_COSTS_INTERVAL: Duration = Duration::from_secs(60 * 60);
 
+/// Max number of transactions in a single packet.
+const MAX_TRANSACTIONS_TO_PROPAGATE: usize = 64;
+
 // minimum interval between updates.
 const UPDATE_INTERVAL: Duration = Duration::from_millis(5000);
 
@@ -647,7 +650,7 @@ impl LightProtocol {
 	fn propagate_transactions(&self, io: &IoContext) {
 		if self.capabilities.read().tx_relay { return }
 
-		let ready_transactions = self.provider.ready_transactions();
+		let ready_transactions = self.provider.ready_transactions(MAX_TRANSACTIONS_TO_PROPAGATE);
 		if ready_transactions.is_empty() { return }
 
 		trace!(target: "pip", "propagate transactions: {} ready", ready_transactions.len());

ethcore/light/src/net/tests/mod.rs

@@ -173,8 +173,8 @@ impl Provider for TestProvider {
 		})
 	}
 
-	fn ready_transactions(&self) -> Vec<PendingTransaction> {
-		self.0.client.ready_transactions()
+	fn ready_transactions(&self, max_len: usize) -> Vec<PendingTransaction> {
+		self.0.client.ready_transactions(max_len)
 	}
 }
 

ethcore/light/src/provider.rs

@@ -125,7 +125,7 @@ pub trait Provider: Send + Sync {
 	fn header_proof(&self, req: request::CompleteHeaderProofRequest) -> Option<request::HeaderProofResponse>;
 
 	/// Provide pending transactions.
-	fn ready_transactions(&self) -> Vec<PendingTransaction>;
+	fn ready_transactions(&self, max_len: usize) -> Vec<PendingTransaction>;
 
 	/// Provide a proof-of-execution for the given transaction proof request.
 	/// Returns a vector of all state items necessary to execute the transaction.
@@ -280,8 +280,8 @@ impl<T: ProvingBlockChainClient + ?Sized> Provider for T {
 			.map(|(_, proof)| ::request::ExecutionResponse { items: proof })
 	}
 
-	fn ready_transactions(&self) -> Vec<PendingTransaction> {
-		BlockChainClient::ready_transactions(self)
+	fn ready_transactions(&self, max_len: usize) -> Vec<PendingTransaction> {
+		BlockChainClient::ready_transactions(self, max_len)
 			.into_iter()
 			.map(|tx| tx.pending().clone())
 			.collect()
@@ -367,9 +367,12 @@ impl<L: AsLightClient + Send + Sync> Provider for LightProvider<L> {
 		None
 	}
 
-	fn ready_transactions(&self) -> Vec<PendingTransaction> {
+	fn ready_transactions(&self, max_len: usize) -> Vec<PendingTransaction> {
 		let chain_info = self.chain_info();
-		self.txqueue.read().ready_transactions(chain_info.best_block_number, chain_info.best_block_timestamp)
+		let mut transactions = self.txqueue.read()
+			.ready_transactions(chain_info.best_block_number, chain_info.best_block_timestamp);
+		transactions.truncate(max_len);
+		transactions
 	}
 }