Transactionpool: Make `ready_at` return earlier (#8995)

`ready_at` returns when we have processed the requested block. However,
on startup we already have processed the best block and there
are no transactions in the pool on startup anyway. So, we can set `updated_at`
to the best block on startup.

Besides that `ready_at` now returns early when there are no ready nor
any future transactions in the pool.

substrate/client/consensus/manual-seal/src/lib.rs

@@ -296,7 +296,13 @@ mod tests {
 		let client = Arc::new(client);
 		let spawner = sp_core::testing::TaskExecutor::new();
 		let pool = Arc::new(BasicPool::with_revalidation_type(
-			Options::default(), true.into(), api(), None, RevalidationType::Full, spawner.clone(),
+			Options::default(),
+			true.into(),
+			api(),
+			None,
+			RevalidationType::Full,
+			spawner.clone(),
+			0,
 		));
 		let env = ProposerFactory::new(
 			spawner.clone(),
@@ -373,6 +379,7 @@ mod tests {
 			None,
 			RevalidationType::Full,
 			spawner.clone(),
+			0,
 		));
 		let env = ProposerFactory::new(
 			spawner.clone(),
@@ -453,6 +460,7 @@ mod tests {
 			None,
 			RevalidationType::Full,
 			spawner.clone(),
+			0,
 		));
 		let env = ProposerFactory::new(
 			spawner.clone(),

substrate/client/transaction-pool/src/lib.rs

@@ -98,6 +98,13 @@ impl<T, Block: BlockT> Default for ReadyPoll<T, Block> {
 }
 
 impl<T, Block: BlockT> ReadyPoll<T, Block> {
+	fn new(best_block_number: NumberFor<Block>) -> Self {
+		Self {
+			updated_at: best_block_number,
+			pollers: Default::default(),
+		}
+	}
+
 	fn trigger(&mut self, number: NumberFor<Block>, iterator_factory: impl Fn() -> T) {
 		self.updated_at = number;
 
@@ -189,6 +196,7 @@ impl<PoolApi, Block> BasicPool<PoolApi, Block>
 		prometheus: Option<&PrometheusRegistry>,
 		revalidation_type: RevalidationType,
 		spawner: impl SpawnNamed,
+		best_block_number: NumberFor<Block>,
 	) -> Self {
 		let pool = Arc::new(sc_transaction_graph::Pool::new(options, is_validator, pool_api.clone()));
 		let (revalidation_queue, background_task) = match revalidation_type {
@@ -213,7 +221,7 @@ impl<PoolApi, Block> BasicPool<PoolApi, Block>
 					RevalidationType::Full => RevalidationStrategy::Always,
 				}
 			)),
-			ready_poll: Default::default(),
+			ready_poll: Arc::new(Mutex::new(ReadyPoll::new(best_block_number))),
 			metrics: PrometheusMetrics::new(prometheus),
 		}
 	}
@@ -309,21 +317,29 @@ impl<PoolApi, Block> TransactionPool for BasicPool<PoolApi, Block>
 	}
 
 	fn ready_at(&self, at: NumberFor<Self::Block>) -> PolledIterator<PoolApi> {
+		let status = self.status();
+		// If there are no transactions in the pool, it is fine to return early.
+		//
+		// There could be transaction being added because of some re-org happening at the relevant
+		// block, but this is relative unlikely.
+		if status.ready == 0 && status.future == 0 {
+			return async { Box::new(std::iter::empty()) as Box<_> }.boxed()
+		}
+
 		if self.ready_poll.lock().updated_at() >= at {
 			log::trace!(target: "txpool", "Transaction pool already processed block  #{}", at);
 			let iterator: ReadyIteratorFor<PoolApi> = Box::new(self.pool.validated_pool().ready());
-			return Box::pin(futures::future::ready(iterator));
+			return async move { iterator }.boxed();
 		}
 
-		Box::pin(
-			self.ready_poll
-				.lock()
-				.add(at)
-				.map(|received| received.unwrap_or_else(|e| {
-					log::warn!("Error receiving pending set: {:?}", e);
-					Box::new(vec![].into_iter())
-				}))
-		)
+		self.ready_poll
+			.lock()
+			.add(at)
+			.map(|received| received.unwrap_or_else(|e| {
+				log::warn!("Error receiving pending set: {:?}", e);
+				Box::new(std::iter::empty())
+			}))
+			.boxed()
 	}
 
 	fn ready(&self) -> ReadyIteratorFor<PoolApi> {
@@ -334,7 +350,7 @@ impl<PoolApi, Block> TransactionPool for BasicPool<PoolApi, Block>
 impl<Block, Client, Fetcher> LightPool<Block, Client, Fetcher>
 where
 	Block: BlockT,
-	Client: sp_blockchain::HeaderBackend<Block> + 'static,
+	Client: sp_blockchain::HeaderBackend<Block> + sc_client_api::UsageProvider<Block> + 'static,
 	Fetcher: sc_client_api::Fetcher<Block> + 'static,
 {
 	/// Create new basic transaction pool for a light node with the provided api.
@@ -345,9 +361,15 @@ where
 		client: Arc<Client>,
 		fetcher: Arc<Fetcher>,
 	) -> Self {
-		let pool_api = Arc::new(LightChainApi::new(client, fetcher));
+		let pool_api = Arc::new(LightChainApi::new(client.clone(), fetcher));
 		Self::with_revalidation_type(
-			options, false.into(), pool_api, prometheus, RevalidationType::Light, spawner,
+			options,
+			false.into(),
+			pool_api,
+			prometheus,
+			RevalidationType::Light,
+			spawner,
+			client.usage_info().chain.best_number,
 		)
 	}
 }
@@ -357,8 +379,12 @@ where
 	Block: BlockT,
 	Client: sp_api::ProvideRuntimeApi<Block>
 		+ sc_client_api::BlockBackend<Block>
-		+ sp_runtime::traits::BlockIdTo<Block>,
-	Client: sc_client_api::ExecutorProvider<Block> + Send + Sync + 'static,
+		+ sp_runtime::traits::BlockIdTo<Block>
+		+ sc_client_api::ExecutorProvider<Block>
+		+ sc_client_api::UsageProvider<Block>
+		+ Send
+		+ Sync
+		+ 'static,
 	Client::Api: sp_transaction_pool::runtime_api::TaggedTransactionQueue<Block>,
 {
 	/// Create new basic transaction pool for a full node with the provided api.
@@ -371,7 +397,13 @@ where
 	) -> Arc<Self> {
 		let pool_api = Arc::new(FullChainApi::new(client.clone(), prometheus));
 		let pool = Arc::new(Self::with_revalidation_type(
-			options, is_validator, pool_api, prometheus, RevalidationType::Full, spawner
+			options,
+			is_validator,
+			pool_api,
+			prometheus,
+			RevalidationType::Full,
+			spawner,
+			client.usage_info().chain.best_number,
 		));
 
 		// make transaction pool available for off-chain runtime calls.