Actually fix major sync detection (#12114)

* Actually fix major sync detection

* Introduce `SyncState::Importing` state

* Add target to SyncState enum variants and add `is_major_syncing` method on it

* Remove unnecessary duplicated `best_seen_block` from `SyncState` struct

* Revert "Remove unnecessary duplicated `best_seen_block` from `SyncState` struct"

This reverts commit bb8abd4.

* Add missing `websocket` feature to `libp2p`

Co-authored-by: parity-processbot <>

client/informant/src/display.rs

@@ -93,42 +93,37 @@ impl<B: BlockT> InformantDisplay<B> {
 			(diff_bytes_inbound, diff_bytes_outbound)
 		};
 
-		let (level, status, target) = match (
-			net_status.sync_state,
-			net_status.best_seen_block,
-			net_status.state_sync,
-			net_status.warp_sync,
-		) {
-			(
-				_,
-				_,
-				_,
-				Some(WarpSyncProgress { phase: WarpSyncPhase::DownloadingBlocks(n), .. }),
-			) => ("⏩", "Block history".into(), format!(", #{}", n)),
-			(_, _, _, Some(warp)) => (
-				"⏩",
-				"Warping".into(),
-				format!(
-					", {}, {:.2} Mib",
-					warp.phase,
-					(warp.total_bytes as f32) / (1024f32 * 1024f32)
+		let (level, status, target) =
+			match (net_status.sync_state, net_status.state_sync, net_status.warp_sync) {
+				(
+					_,
+					_,
+					Some(WarpSyncProgress { phase: WarpSyncPhase::DownloadingBlocks(n), .. }),
+				) => ("⏩", "Block history".into(), format!(", #{}", n)),
+				(_, _, Some(warp)) => (
+					"⏩",
+					"Warping".into(),
+					format!(
+						", {}, {:.2} Mib",
+						warp.phase,
+						(warp.total_bytes as f32) / (1024f32 * 1024f32)
+					),
 				),
-			),
-			(_, _, Some(state), _) => (
-				"⚙️ ",
-				"Downloading state".into(),
-				format!(
-					", {}%, {:.2} Mib",
-					state.percentage,
-					(state.size as f32) / (1024f32 * 1024f32)
+				(_, Some(state), _) => (
+					"⚙️ ",
+					"Downloading state".into(),
+					format!(
+						", {}%, {:.2} Mib",
+						state.percentage,
+						(state.size as f32) / (1024f32 * 1024f32)
+					),
 				),
-			),
-			(SyncState::Idle, _, _, _) => ("💤", "Idle".into(), "".into()),
-			(SyncState::Downloading, None, _, _) =>
-				("⚙️ ", format!("Preparing{}", speed), "".into()),
-			(SyncState::Downloading, Some(n), None, _) =>
-				("⚙️ ", format!("Syncing{}", speed), format!(", target=#{}", n)),
-		};
+				(SyncState::Idle, _, _) => ("💤", "Idle".into(), "".into()),
+				(SyncState::Downloading { target }, _, _) =>
+					("⚙️ ", format!("Syncing{}", speed), format!(", target=#{target}")),
+				(SyncState::Importing { target }, _, _) =>
+					("⚙️ ", format!("Preparing{}", speed), format!(", target=#{target}")),
+			};
 
 		if self.format.enable_color {
 			info!(

client/network/Cargo.toml

@@ -26,7 +26,7 @@ fnv = "1.0.6"
 futures = "0.3.21"
 futures-timer = "3.0.2"
 ip_network = "0.4.1"
-libp2p = { version = "0.49.0", features = ["async-std", "dns", "identify", "kad", "mdns-async-io", "mplex", "noise", "ping", "tcp", "yamux"] }
+libp2p = { version = "0.49.0", features = ["async-std", "dns", "identify", "kad", "mdns-async-io", "mplex", "noise", "ping", "tcp", "yamux", "websocket"] }
 linked_hash_set = "0.1.3"
 linked-hash-map = "0.5.4"
 log = "0.4.17"

client/network/common/src/service.rs

@@ -98,7 +98,7 @@ where
 #[derive(Clone)]
 pub struct NetworkStatus<B: BlockT> {
 	/// Current global sync state.
-	pub sync_state: SyncState,
+	pub sync_state: SyncState<NumberFor<B>>,
 	/// Target sync block number.
 	pub best_seen_block: Option<NumberFor<B>>,
 	/// Number of peers participating in syncing.

client/network/common/src/sync.rs

@@ -44,11 +44,20 @@ pub struct PeerInfo<Block: BlockT> {
 
 /// Reported sync state.
 #[derive(Clone, Eq, PartialEq, Debug)]
-pub enum SyncState {
+pub enum SyncState<BlockNumber> {
 	/// Initial sync is complete, keep-up sync is active.
 	Idle,
 	/// Actively catching up with the chain.
-	Downloading,
+	Downloading { target: BlockNumber },
+	/// All blocks are downloaded and are being imported.
+	Importing { target: BlockNumber },
+}
+
+impl<BlockNumber> SyncState<BlockNumber> {
+	/// Are we actively catching up with the chain?
+	pub fn is_major_syncing(&self) -> bool {
+		!matches!(self, SyncState::Idle)
+	}
 }
 
 /// Reported state download progress.
@@ -64,7 +73,7 @@ pub struct StateDownloadProgress {
 #[derive(Clone)]
 pub struct SyncStatus<Block: BlockT> {
 	/// Current global sync state.
-	pub state: SyncState,
+	pub state: SyncState<NumberFor<Block>>,
 	/// Target sync block number.
 	pub best_seen_block: Option<NumberFor<Block>>,
 	/// Number of peers participating in syncing.

client/network/src/service.rs

@@ -70,7 +70,7 @@ use sc_network_common::{
 		NotificationSender as NotificationSenderT, NotificationSenderError,
 		NotificationSenderReady as NotificationSenderReadyT, Signature, SigningError,
 	},
-	sync::{SyncState, SyncStatus},
+	sync::SyncStatus,
 	ExHashT,
 };
 use sc_peerset::PeersetHandle;
@@ -1997,11 +1997,13 @@ where
 			*this.external_addresses.lock() = external_addresses;
 		}
 
-		let is_major_syncing =
-			match this.network_service.behaviour_mut().user_protocol_mut().sync_state().state {
-				SyncState::Idle => false,
-				SyncState::Downloading => true,
-			};
+		let is_major_syncing = this
+			.network_service
+			.behaviour_mut()
+			.user_protocol_mut()
+			.sync_state()
+			.state
+			.is_major_syncing();
 
 		this.is_major_syncing.store(is_major_syncing, Ordering::Relaxed);
 

client/network/sync/src/lib.rs

@@ -410,13 +410,21 @@ where
 
 	/// Returns the current sync status.
 	fn status(&self) -> SyncStatus<B> {
-		let best_seen = self.best_seen();
-		let sync_state = if let Some(n) = best_seen {
+		let median_seen = self.median_seen();
+		let best_seen_block =
+			median_seen.and_then(|median| (median > self.best_queued_number).then_some(median));
+		let sync_state = if let Some(target) = median_seen {
 			// A chain is classified as downloading if the provided best block is
-			// more than `MAJOR_SYNC_BLOCKS` behind the best block.
+			// more than `MAJOR_SYNC_BLOCKS` behind the best block or as importing
+			// if the same can be said about queued blocks.
 			let best_block = self.client.info().best_number;
-			if n > best_block && n - best_block > MAJOR_SYNC_BLOCKS.into() {
-				SyncState::Downloading
+			if target > best_block && target - best_block > MAJOR_SYNC_BLOCKS.into() {
+				// If target is not queued, we're downloading, otherwise importing.
+				if target > self.best_queued_number {
+					SyncState::Downloading { target }
+				} else {
+					SyncState::Importing { target }
+				}
 			} else {
 				SyncState::Idle
 			}
@@ -437,7 +445,7 @@ where
 
 		SyncStatus {
 			state: sync_state,
-			best_seen_block: best_seen,
+			best_seen_block,
 			num_peers: self.peers.len() as u32,
 			queued_blocks: self.queue_blocks.len() as u32,
 			state_sync: self.state_sync.as_ref().map(|s| s.progress()),
@@ -693,7 +701,7 @@ where
 			trace!(target: "sync", "Too many blocks in the queue.");
 			return Box::new(std::iter::empty())
 		}
-		let major_sync = self.status().state == SyncState::Downloading;
+		let is_major_syncing = self.status().state.is_major_syncing();
 		let attrs = self.required_block_attributes();
 		let blocks = &mut self.blocks;
 		let fork_targets = &mut self.fork_targets;
@@ -703,7 +711,7 @@ where
 		let client = &self.client;
 		let queue = &self.queue_blocks;
 		let allowed_requests = self.allowed_requests.take();
-		let max_parallel = if major_sync { 1 } else { self.max_parallel_downloads };
+		let max_parallel = if is_major_syncing { 1 } else { self.max_parallel_downloads };
 		let gap_sync = &mut self.gap_sync;
 		let iter = self.peers.iter_mut().filter_map(move |(&id, peer)| {
 			if !peer.state.is_available() || !allowed_requests.contains(&id) {
@@ -1797,8 +1805,8 @@ where
 		Ok((sync, Box::new(ChainSyncInterfaceHandle::new(tx))))
 	}
 
-	/// Returns the best seen block number if we don't have that block yet, `None` otherwise.
-	fn best_seen(&self) -> Option<NumberFor<B>> {
+	/// Returns the median seen block number.
+	fn median_seen(&self) -> Option<NumberFor<B>> {
 		let mut best_seens = self.peers.values().map(|p| p.best_number).collect::<Vec<_>>();
 
 		if best_seens.is_empty() {
@@ -1807,12 +1815,7 @@ where
 			let middle = best_seens.len() / 2;
 
 			// Not the "perfect median" when we have an even number of peers.
-			let median = *best_seens.select_nth_unstable(middle).1;
-			if median > self.best_queued_number {
-				Some(median)
-			} else {
-				None
-			}
+			Some(*best_seens.select_nth_unstable(middle).1)
 		}
 	}
 
@@ -1854,7 +1857,7 @@ where
 			);
 		}
 
-		let origin = if !gap && self.status().state != SyncState::Downloading {
+		let origin = if !gap && !self.status().state.is_major_syncing() {
 			BlockOrigin::NetworkBroadcast
 		} else {
 			BlockOrigin::NetworkInitialSync