Consolidate subsystem spans so they are all children of the leaf-activated root span (#6458)

* Pass the PerLeafSpan as mutable reference to handle_new_head function * cargo +nightly fmt --all * Add mock span for test * cargo +nightly fmt --all * add new-blocks-hashes to span * ref span in match statement, set span to disabled if not passed * remove second match clause, make handle_new_head_span mutable * cargo +nightly fmt --all * improve tag on error and warning * add imported blocks and info span * cargo +nightly fmt --all * Improve error for imported_blocks_and_info trace * format tags on get_header_span * add lost-to-finality tag * add missing bracket * - Add bitfield child span - Add block db insertion span * - fix update-bitfield span tag * - Fix type conversion to u64 - Add missing argument * - Cargo fmt * - Test add_follows_from * - Revert as relationship between spans not working correctly * - use drop to test if parent-child relationship can be re-established * - remove bitfield span, check if parent-child relationship can be reestablished * - Remove dangling bitfield span which is not used, to see if parent-child relationship can be re-established * Another dangling bitfield span * cargo fmt * - add imported blocks and info span - add candidate span per candidate * add tags before moving block_header to push scope * - Add db-insertion span * cargo fmt * fix types * * Pass mutable reference to span in handle_new_head * Change get-header-span tags in handle_new_head * Create cache-session-info span in handle_new_head * Create optional argument in determine_new_blocks * Pass mutable reference to handle_new_head_span in determine_new_blocks in handle_new_head function * Add candidate-hash, candidate-number, lost-to-finality tags to candidate_span in handle_new_head function * Manually drop db_insertion_span and remove superfluous tags to it, only keeping approved-bitfields tag * Add ApprovalVoting stage in jaeger * * Pass mutable reference to jaeger::Span in stead of PerLeafSpan * Add block-import span * *Pass optional_span (optional argument) to determine_new_blocks util function * * Add num-candidates int tag to block_import_span * * Add head tag to cache_session_span * * Create PerLeafSpan in handle_from_overseer (this is required to establish parent-child relationship between approval-voting span, and leaf-activated root span) * * Add candidate-import-span as child of block-import-span * Add candidate-hash and num-approval tags to candidate-import-span * * Fix num-candidate tag to bitvec-len tag in candidate-import-span * *Fix imported_blocKs_and_info span to create new-block-span as not dealing with candidates * Consider the future::select! block * Use HashMap<Hash, jaeger::PerLeafSpan> * Remove Stage 9 * Add missing spans * cargo +nightly fmt --all * Remove optional span argument for determine_new_blocks * * Remove no-longer needed default PerLeafSpan implementation * Remove no-longer necessary mock span given re-factoring of handle_new_head() no longer neeing mutable span * Split validation-result and request-data (availability and validation code) spans into two by dropping request_validation_data_spans * Remove drop statements for cache_session_info_span * * Remove unnecessary span * Remove another excessively spammy span * Add missing spans from State in import tests * Use functional approach to get spans * - Add functional approach for the approval-voting span - Add doc on block_numbers given labelling ambiguity - Add span pruning logic - Use .add_para_id on validation_result_span * Replace for hash_set in hash_set_iter with map closure * cargo +nightly fmt --all * Change from unconsumed `map` to `.for_each` * cargo +nightly fmt --all * Refactor add_para_id to validation_result_span * cargo +nightly fmt --all * Remove duplicate tag * Add missing tag to handle-approved-ancestor span * Refactor span pruning to only invoke retain once * Typo in span name * - Replace unwrap_or with unwrap_or_else due to lazy evaluation of trace-identifier in polkadot_node_jaeger - Remove some redundant spans * Add approval-distribution spans * - Add unwrap_or_else on note-approved-in-chain-selection - Use child_with_trace_id to add traceID string tag on span (note this does not change the traceID, but just adds a tag) * cargo +nightly fmt --all * - Add traceID tags were necessary in approval-voting and availability-distribution - Always use block-hash tag in stead of relay-parent tag in approval-distribution * Remove schedule-wakeup span as it will duplicate spans on existing wakeups (which should be a no-op) * Remove a couple of warnings related to mutability * Fix failing tests in availability distribution * Add traceID tag to launch-approval and validation-result * Reshuffle the validation and validation result spans to where more appropriate and add block-hash tag * - Add tranche and should-trigger tag to process-wakeup span - Add candidate-hash and traceID to check-and-import-approval span * cargo fmt * - Adjustments after PR comments * Move span pruning after other pruning logic * Remove DerefMut - no longer needed * Relabel request-chunk spans * - Fix typo in span label - Add docs for drops * Add new approval-voting span pruning logic * Undo removal of ! * cargo fmt
2026-06-01 02:11:01 +00:00 · 2023-03-31 16:54:19 +01:00
parent 9fe528d5c7
commit 713f6625fa
12 changed files with 349 additions and 90 deletions
@@ -6559,6 +6559,7 @@ dependencies = [
 "env_logger 0.9.0",
 "futures",
 "log",
+ "polkadot-node-jaeger",
 "polkadot-node-metrics",
 "polkadot-node-network-protocol",
 "polkadot-node-primitives",
@@ -329,13 +329,17 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 	finalized_number: &Option<BlockNumber>,
 ) -> SubsystemResult<Vec<BlockImportedCandidates>> {
 	const MAX_HEADS_LOOK_BACK: BlockNumber = MAX_FINALITY_LAG;
-
-	let mut span = jaeger::Span::new(head, "approval-checking-import");
+	let _handle_new_head_span = state
+		.spans
+		.get(&head)
+		.map(|span| span.child("handle-new-head"))
+		.unwrap_or_else(|| jaeger::Span::new(head, "handle-new-head"))
+		.with_string_tag("head", format!("{:?}", head))
+		.with_stage(jaeger::Stage::ApprovalChecking);

 	let header = {
 		let (h_tx, h_rx) = oneshot::channel();
 		ctx.send_message(ChainApiMessage::BlockHeader(head, h_tx)).await;
-
 		match h_rx.await? {
 			Err(e) => {
 				gum::debug!(
@@ -343,11 +347,12 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 					"Chain API subsystem temporarily unreachable {}",
 					e,
 				);
-
+				// May be a better way of handling errors here.
 				return Ok(Vec::new())
 			},
 			Ok(None) => {
 				gum::warn!(target: LOG_TARGET, "Missing header for new head {}", head);
+				// May be a better way of handling warnings here.
 				return Ok(Vec::new())
 			},
 			Ok(Some(h)) => h,
@@ -363,7 +368,6 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 				?e,
 				"Could not cache session info when processing head.",
 			);
-
 			return Ok(Vec::new())
 		},
 		Ok(Some(a @ SessionWindowUpdate::Advanced { .. })) => {
@@ -391,8 +395,6 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 	.map_err(|e| SubsystemError::with_origin("approval-voting", e))
 	.await?;

-	span.add_uint_tag("new-blocks", new_blocks.len() as u64);
-
 	if new_blocks.is_empty() {
 		return Ok(Vec::new())
 	}
@@ -473,6 +475,7 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 			);
 			(block_tick, no_show_duration)
 		};
+
 		let needed_approvals = session_info.needed_approvals;
 		let validator_group_lens: Vec<usize> =
 			session_info.validator_groups.iter().map(|v| v.len()).collect();
@@ -507,11 +510,9 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 						result.len(),
 					);
 				}
-
 				result
 			}
 		};
-
 		// If all bits are already set, then send an approve message.
 		if approved_bitfield.count_ones() == approved_bitfield.len() {
 			ctx.send_message(ChainSelectionMessage::Approved(block_hash)).await;
@@ -602,7 +603,6 @@ pub(crate) async fn handle_new_head<Context, B: Backend>(
 	);

 	ctx.send_unbounded_message(ApprovalDistributionMessage::NewBlocks(approval_meta));
-
 	Ok(imported_candidates)
 }

@@ -661,6 +661,7 @@ pub(crate) mod tests {
 			assignment_criteria: Box::new(MockAssignmentCriteria),
 			db,
 			db_config: TEST_CONFIG,
+			spans: HashMap::new(),
 		}
 	}

@@ -21,6 +21,7 @@
 //! of others. It uses this information to determine when candidates and blocks have
 //! been sufficiently approved to finalize.

+use jaeger::{hash_to_trace_identifier, PerLeafSpan};
 use polkadot_node_jaeger as jaeger;
 use polkadot_node_primitives::{
 	approval::{
@@ -478,7 +479,11 @@ impl Wakeups {
 		self.wakeups.entry(tick).or_default().push((block_hash, candidate_hash));
 	}

-	fn prune_finalized_wakeups(&mut self, finalized_number: BlockNumber) {
+	fn prune_finalized_wakeups(
+		&mut self,
+		finalized_number: BlockNumber,
+		spans: &mut HashMap<Hash, PerLeafSpan>,
+	) {
 		let after = self.block_numbers.split_off(&(finalized_number + 1));
 		let pruned_blocks: HashSet<_> = std::mem::replace(&mut self.block_numbers, after)
 			.into_iter()
@@ -502,6 +507,9 @@ impl Wakeups {
 				}
 			}
 		}
+
+		// Remove all spans that are associated with pruned blocks.
+		spans.retain(|h, _| !pruned_blocks.contains(h));
 	}

 	// Get the wakeup for a particular block/candidate combo, if any.
@@ -639,6 +647,7 @@ struct State {
 	// Require for `RollingSessionWindow`.
 	db_config: DatabaseConfig,
 	db: Arc<dyn Database>,
+	spans: HashMap<Hash, jaeger::PerLeafSpan>,
 }

 #[overseer::contextbounds(ApprovalVoting, prefix = self::overseer)]
@@ -777,6 +786,7 @@ where
 		assignment_criteria,
 		db_config: subsystem.db_config,
 		db: subsystem.db,
+		spans: HashMap::new(),
 	};

 	let mut wakeups = Wakeups::default();
@@ -798,14 +808,13 @@ where
 	loop {
 		let mut overlayed_db = OverlayedBackend::new(&backend);
 		let actions = futures::select! {
-			(tick, woken_block, woken_candidate) = wakeups.next(&*state.clock).fuse() => {
+			(_tick, woken_block, woken_candidate) = wakeups.next(&*state.clock).fuse() => {
 				subsystem.metrics.on_wakeup();
 				process_wakeup(
 					&mut state,
 					&mut overlayed_db,
 					woken_block,
 					woken_candidate,
-					tick,
 					&subsystem.metrics,
 				)?
 			}
@@ -878,7 +887,6 @@ where

 		if !overlayed_db.is_empty() {
 			let _timer = subsystem.metrics.time_db_transaction();
-
 			let ops = overlayed_db.into_write_ops();
 			backend.write(ops)?;
 		}
@@ -919,12 +927,12 @@ async fn handle_actions<Context>(
 	actions: Vec<Action>,
 ) -> SubsystemResult<bool> {
 	let mut conclude = false;
-
 	let mut actions_iter = actions.into_iter();
 	while let Some(action) = actions_iter.next() {
 		match action {
-			Action::ScheduleWakeup { block_hash, block_number, candidate_hash, tick } =>
-				wakeups.schedule(block_hash, block_number, candidate_hash, tick),
+			Action::ScheduleWakeup { block_hash, block_number, candidate_hash, tick } => {
+				wakeups.schedule(block_hash, block_number, candidate_hash, tick);
+			},
 			Action::IssueApproval(candidate_hash, approval_request) => {
 				// Note that the IssueApproval action will create additional
 				// actions that will need to all be processed before we can
@@ -968,8 +976,18 @@ async fn handle_actions<Context>(
 					continue
 				}

+				let mut launch_approval_span = state
+					.spans
+					.get(&relay_block_hash)
+					.map(|span| span.child("launch-approval"))
+					.unwrap_or_else(|| jaeger::Span::new(candidate_hash, "launch-approval"))
+					.with_trace_id(candidate_hash)
+					.with_candidate(candidate_hash)
+					.with_stage(jaeger::Stage::ApprovalChecking);
+
 				metrics.on_assignment_produced(assignment_tranche);
 				let block_hash = indirect_cert.block_hash;
+				launch_approval_span.add_string_tag("block-hash", format!("{:?}", block_hash));
 				let validator_index = indirect_cert.validator;

 				ctx.send_unbounded_message(ApprovalDistributionMessage::DistributeAssignment(
@@ -1004,6 +1022,7 @@ async fn handle_actions<Context>(
 										validator_index,
 										block_hash,
 										backing_group,
+										&launch_approval_span,
 									)
 									.await
 								},
@@ -1014,12 +1033,21 @@ async fn handle_actions<Context>(
 				}
 			},
 			Action::NoteApprovedInChainSelection(block_hash) => {
+				let _span = state
+					.spans
+					.get(&block_hash)
+					.map(|span| span.child("note-approved-in-chain-selection"))
+					.unwrap_or_else(|| {
+						jaeger::Span::new(block_hash, "note-approved-in-chain-selection")
+					})
+					.with_string_tag("block-hash", format!("{:?}", block_hash))
+					.with_stage(jaeger::Stage::ApprovalChecking);
 				ctx.send_message(ChainSelectionMessage::Approved(block_hash)).await;
 			},
 			Action::BecomeActive => {
 				*mode = Mode::Active;

-				let messages = distribution_messages_for_activation(overlayed_db)?;
+				let messages = distribution_messages_for_activation(overlayed_db, state)?;

 				ctx.send_messages(messages.into_iter()).await;
 			},
@@ -1034,6 +1062,7 @@ async fn handle_actions<Context>(

 fn distribution_messages_for_activation(
 	db: &OverlayedBackend<'_, impl Backend>,
+	state: &mut State,
 ) -> SubsystemResult<Vec<ApprovalDistributionMessage>> {
 	let all_blocks: Vec<Hash> = db.load_all_blocks()?;

@@ -1043,6 +1072,15 @@ fn distribution_messages_for_activation(
 	messages.push(ApprovalDistributionMessage::NewBlocks(Vec::new())); // dummy value.

 	for block_hash in all_blocks {
+		let mut distribution_message_span = state
+			.spans
+			.get(&block_hash)
+			.map(|span| span.child("distribution-messages-for-activation"))
+			.unwrap_or_else(|| {
+				jaeger::Span::new(block_hash, "distribution-messages-for-activation")
+			})
+			.with_stage(jaeger::Stage::ApprovalChecking)
+			.with_string_tag("block-hash", format!("{:?}", block_hash));
 		let block_entry = match db.load_block_entry(&block_hash)? {
 			Some(b) => b,
 			None => {
@@ -1051,6 +1089,10 @@ fn distribution_messages_for_activation(
 				continue
 			},
 		};
+
+		distribution_message_span.add_string_tag("block-hash", &block_hash.to_string());
+		distribution_message_span
+			.add_string_tag("parent-hash", &block_entry.parent_hash().to_string());
 		approval_meta.push(BlockApprovalMeta {
 			hash: block_hash,
 			number: block_entry.block_number(),
@@ -1061,6 +1103,8 @@ fn distribution_messages_for_activation(
 		});

 		for (i, (_, candidate_hash)) in block_entry.candidates().iter().enumerate() {
+			let _candidate_span =
+				distribution_message_span.child("candidate").with_candidate(*candidate_hash);
 			let candidate_entry = match db.load_candidate_entry(&candidate_hash)? {
 				Some(c) => c,
 				None => {
@@ -1140,9 +1184,11 @@ async fn handle_from_overseer<Context>(
 	let actions = match x {
 		FromOrchestra::Signal(OverseerSignal::ActiveLeaves(update)) => {
 			let mut actions = Vec::new();
-
 			if let Some(activated) = update.activated {
 				let head = activated.hash;
+				let approval_voting_span =
+					jaeger::PerLeafSpan::new(activated.span, "approval-voting");
+				state.spans.insert(head, approval_voting_span);
 				match import::handle_new_head(ctx, state, db, head, &*last_finalized_height).await {
 					Err(e) => return Err(SubsystemError::with_origin("db", e)),
 					Ok(block_imported_candidates) => {
@@ -1199,7 +1245,12 @@ async fn handle_from_overseer<Context>(
 			crate::ops::canonicalize(db, block_number, block_hash)
 				.map_err(|e| SubsystemError::with_origin("db", e))?;

-			wakeups.prune_finalized_wakeups(block_number);
+			// `prune_finalized_wakeups` prunes all finalized block hashes. We prune spans accordingly.
+			wakeups.prune_finalized_wakeups(block_number, &mut state.spans);
+
+			// // `prune_finalized_wakeups` prunes all finalized block hashes. We prune spans accordingly.
+			// let hash_set = wakeups.block_numbers.values().flatten().collect::<HashSet<_>>();
+			// state.spans.retain(|hash, _| hash_set.contains(hash));

 			Vec::new()
 		},
@@ -1220,7 +1271,23 @@ async fn handle_from_overseer<Context>(
 				})?
 				.0,
 			ApprovalVotingMessage::ApprovedAncestor(target, lower_bound, res) => {
-				match handle_approved_ancestor(ctx, db, target, lower_bound, wakeups).await {
+				let mut approved_ancestor_span = state
+					.spans
+					.get(&target)
+					.map(|span| span.child("approved-ancestor"))
+					.unwrap_or_else(|| jaeger::Span::new(target, "approved-ancestor"))
+					.with_stage(jaeger::Stage::ApprovalChecking)
+					.with_string_tag("leaf", format!("{:?}", target));
+				match handle_approved_ancestor(
+					ctx,
+					db,
+					target,
+					lower_bound,
+					wakeups,
+					&mut approved_ancestor_span,
+				)
+				.await
+				{
 					Ok(v) => {
 						let _ = res.send(v);
 					},
@@ -1342,15 +1409,15 @@ async fn handle_approved_ancestor<Context>(
 	target: Hash,
 	lower_bound: BlockNumber,
 	wakeups: &Wakeups,
+	span: &mut jaeger::Span,
 ) -> SubsystemResult<Option<HighestApprovedAncestorBlock>> {
 	const MAX_TRACING_WINDOW: usize = 200;
 	const ABNORMAL_DEPTH_THRESHOLD: usize = 5;
-
+	let mut span = span
+		.child("handle-approved-ancestor")
+		.with_stage(jaeger::Stage::ApprovalChecking);
 	use bitvec::{order::Lsb0, vec::BitVec};

-	let mut span =
-		jaeger::Span::new(&target, "approved-ancestor").with_stage(jaeger::Stage::ApprovalChecking);
-
 	let mut all_approved_max = None;

 	let target_number = {
@@ -1365,13 +1432,12 @@ async fn handle_approved_ancestor<Context>(
 		}
 	};

+	span.add_uint_tag("leaf-number", target_number as u64);
+	span.add_uint_tag("lower-bound", lower_bound as u64);
 	if target_number <= lower_bound {
 		return Ok(None)
 	}

-	span.add_string_fmt_debug_tag("target-number", target_number);
-	span.add_string_fmt_debug_tag("target-hash", target);
-
 	// request ancestors up to but not including the lower bound,
 	// as a vote on the lower bound is implied if we cannot find
 	// anything else.
@@ -1397,6 +1463,9 @@ async fn handle_approved_ancestor<Context>(

 	let mut bits: BitVec<u8, Lsb0> = Default::default();
 	for (i, block_hash) in std::iter::once(target).chain(ancestry).enumerate() {
+		let mut entry_span =
+			span.child("load-block-entry").with_stage(jaeger::Stage::ApprovalChecking);
+		entry_span.add_string_tag("block-hash", format!("{:?}", block_hash));
 		// Block entries should be present as the assumption is that
 		// nothing here is finalized. If we encounter any missing block
 		// entries we can fail.
@@ -1452,7 +1521,7 @@ async fn handle_approved_ancestor<Context>(
 				unapproved.len(),
 				entry.candidates().len(),
 			);
-
+			entry_span.add_uint_tag("unapproved-candidates", unapproved.len() as u64);
 			for candidate_hash in unapproved {
 				match db.load_candidate_entry(&candidate_hash)? {
 					None => {
@@ -1575,8 +1644,8 @@ async fn handle_approved_ancestor<Context>(
 		});
 	match all_approved_max {
 		Some(HighestApprovedAncestorBlock { ref hash, ref number, .. }) => {
-			span.add_uint_tag("approved-number", *number as u64);
-			span.add_string_fmt_debug_tag("approved-hash", hash);
+			span.add_uint_tag("highest-approved-number", *number as u64);
+			span.add_string_fmt_debug_tag("highest-approved-hash", hash);
 		},
 		None => {
 			span.add_string_tag("reached-lower-bound", "true");
@@ -1677,6 +1746,15 @@ fn check_and_import_assignment(
 ) -> SubsystemResult<(AssignmentCheckResult, Vec<Action>)> {
 	let tick_now = state.clock.tick_now();

+	let mut check_and_import_assignment_span = state
+		.spans
+		.get(&assignment.block_hash)
+		.map(|span| span.child("check-and-import-assignment"))
+		.unwrap_or_else(|| jaeger::Span::new(assignment.block_hash, "check-and-import-assignment"))
+		.with_relay_parent(assignment.block_hash)
+		.with_uint_tag("candidate-index", candidate_index as u64)
+		.with_stage(jaeger::Stage::ApprovalChecking);
+
 	let block_entry = match db.load_block_entry(&assignment.block_hash)? {
 		Some(b) => b,
 		None =>
@@ -1711,6 +1789,13 @@ fn check_and_import_assignment(
 				)), // no candidate at core.
 		};

+	check_and_import_assignment_span
+		.add_string_tag("candidate-hash", format!("{:?}", assigned_candidate_hash));
+	check_and_import_assignment_span.add_string_tag(
+		"traceID",
+		format!("{:?}", jaeger::hash_to_trace_identifier(assigned_candidate_hash.0)),
+	);
+
 	let mut candidate_entry = match db.load_candidate_entry(&assigned_candidate_hash)? {
 		Some(c) => c,
 		None =>
@@ -1769,6 +1854,8 @@ fn check_and_import_assignment(
 			},
 		};

+		check_and_import_assignment_span.add_uint_tag("tranche", tranche as u64);
+
 		let is_duplicate = approval_entry.is_assigned(assignment.validator);
 		approval_entry.import_assignment(tranche, assignment.validator, tick_now);

@@ -1822,6 +1909,15 @@ fn check_and_import_approval<T>(
 		}};
 	}

+	let mut span = state
+		.spans
+		.get(&approval.block_hash)
+		.map(|span| span.child("check-and-import-approval"))
+		.unwrap_or_else(|| jaeger::Span::new(approval.block_hash, "check-and-import-approval"))
+		.with_uint_tag("candidate-index", approval.candidate_index as u64)
+		.with_relay_parent(approval.block_hash)
+		.with_stage(jaeger::Stage::ApprovalChecking);
+
 	let block_entry = match db.load_block_entry(&approval.block_hash)? {
 		Some(b) => b,
 		None => {
@@ -1847,6 +1943,12 @@ fn check_and_import_approval<T>(
 		)),
 	};

+	span.add_string_tag("candidate-hash", format!("{:?}", approved_candidate_hash));
+	span.add_string_tag(
+		"traceID",
+		format!("{:?}", hash_to_trace_identifier(approved_candidate_hash.0)),
+	);
+
 	let pubkey = match session_info.validators.get(approval.validator) {
 		Some(k) => k,
 		None => respond_early!(ApprovalCheckResult::Bad(
@@ -2120,16 +2222,17 @@ fn process_wakeup(
 	db: &mut OverlayedBackend<'_, impl Backend>,
 	relay_block: Hash,
 	candidate_hash: CandidateHash,
-	expected_tick: Tick,
 	metrics: &Metrics,
 ) -> SubsystemResult<Vec<Action>> {
-	let _span = jaeger::Span::from_encodable(
-		(relay_block, candidate_hash, expected_tick),
-		"process-approval-wakeup",
-	)
-	.with_relay_parent(relay_block)
-	.with_candidate(candidate_hash)
-	.with_stage(jaeger::Stage::ApprovalChecking);
+	let mut span = state
+		.spans
+		.get(&relay_block)
+		.map(|span| span.child("process-wakeup"))
+		.unwrap_or_else(|| jaeger::Span::new(candidate_hash, "process-wakeup"))
+		.with_trace_id(candidate_hash)
+		.with_relay_parent(relay_block)
+		.with_candidate(candidate_hash)
+		.with_stage(jaeger::Stage::ApprovalChecking);

 	let block_entry = db.load_block_entry(&relay_block)?;
 	let candidate_entry = db.load_candidate_entry(&candidate_hash)?;
@@ -2159,9 +2262,8 @@ fn process_wakeup(
 		state.slot_duration_millis,
 		Slot::from(u64::from(session_info.no_show_slots)),
 	);
-
 	let tranche_now = state.clock.tranche_now(state.slot_duration_millis, block_entry.slot());
-
+	span.add_uint_tag("tranche", tranche_now as u64);
 	gum::trace!(
 		target: LOG_TARGET,
 		tranche = tranche_now,
@@ -2195,6 +2297,8 @@ fn process_wakeup(
 		(should_trigger, approval_entry.backing_group())
 	};

+	gum::trace!(target: LOG_TARGET, "Wakeup processed. Should trigger: {}", should_trigger);
+
 	let mut actions = Vec::new();
 	let candidate_receipt = candidate_entry.candidate_receipt().clone();

@@ -2243,7 +2347,6 @@ fn process_wakeup(
 			});
 		}
 	}
-
 	// Although we checked approval earlier in this function,
 	// this wakeup might have advanced the state to approved via
 	// a no-show that was immediately covered and therefore
@@ -2275,6 +2378,7 @@ async fn launch_approval<Context>(
 	validator_index: ValidatorIndex,
 	block_hash: Hash,
 	backing_group: GroupIndex,
+	span: &jaeger::Span,
 ) -> SubsystemResult<RemoteHandle<ApprovalState>> {
 	let (a_tx, a_rx) = oneshot::channel();
 	let (code_tx, code_rx) = oneshot::channel();
@@ -2306,9 +2410,15 @@ async fn launch_approval<Context>(

 	let candidate_hash = candidate.hash();
 	let para_id = candidate.descriptor.para_id;
-
 	gum::trace!(target: LOG_TARGET, ?candidate_hash, ?para_id, "Recovering data.");

+	let request_validation_data_span = span
+		.child("request-validation-data")
+		.with_trace_id(candidate_hash)
+		.with_candidate(candidate_hash)
+		.with_string_tag("block-hash", format!("{:?}", block_hash))
+		.with_stage(jaeger::Stage::ApprovalChecking);
+
 	let timer = metrics.time_recover_and_approve();
 	ctx.send_message(AvailabilityRecoveryMessage::RecoverAvailableData(
 		candidate.clone(),
@@ -2318,6 +2428,13 @@ async fn launch_approval<Context>(
 	))
 	.await;

+	let request_validation_result_span = span
+		.child("request-validation-result")
+		.with_trace_id(candidate_hash)
+		.with_candidate(candidate_hash)
+		.with_string_tag("block-hash", format!("{:?}", block_hash))
+		.with_stage(jaeger::Stage::ApprovalChecking);
+
 	ctx.send_message(RuntimeApiMessage::Request(
 		block_hash,
 		RuntimeApiRequest::ValidationCodeByHash(candidate.descriptor.validation_code_hash, code_tx),
@@ -2330,10 +2447,6 @@ async fn launch_approval<Context>(
 	let background = async move {
 		// Force the move of the timer into the background task.
 		let _timer = timer;
-		let _span = jaeger::Span::from_encodable((block_hash, candidate_hash), "launch-approval")
-			.with_relay_parent(block_hash)
-			.with_candidate(candidate_hash)
-			.with_stage(jaeger::Stage::ApprovalChecking);

 		let available_data = match a_rx.await {
 			Err(_) => return ApprovalState::failed(validator_index, candidate_hash),
@@ -2371,6 +2484,7 @@ async fn launch_approval<Context>(
 				return ApprovalState::failed(validator_index, candidate_hash)
 			},
 		};
+		drop(request_validation_data_span);

 		let validation_code = match code_rx.await {
 			Err(_) => return ApprovalState::failed(validator_index, candidate_hash),
@@ -2392,7 +2506,6 @@ async fn launch_approval<Context>(
 		};

 		let (val_tx, val_rx) = oneshot::channel();
-
 		sender
 			.send_message(CandidateValidationMessage::ValidateFromExhaustive(
 				available_data.validation_data,
@@ -2430,7 +2543,6 @@ async fn launch_approval<Context>(
 					candidate_hash,
 					candidate.clone(),
 				);
-
 				metrics_guard.take().on_approval_invalid();
 				return ApprovalState::failed(validator_index, candidate_hash)
 			},
@@ -2443,11 +2555,11 @@ async fn launch_approval<Context>(
 					"Failed to validate candidate due to internal error",
 				);
 				metrics_guard.take().on_approval_error();
+				drop(request_validation_result_span);
 				return ApprovalState::failed(validator_index, candidate_hash)
 			},
 		}
 	};
-
 	let (background, remote_handle) = background.remote_handle();
 	ctx.spawn("approval-checks", Box::pin(background)).map(move |()| remote_handle)
 }
@@ -2463,6 +2575,17 @@ async fn issue_approval<Context>(
 	candidate_hash: CandidateHash,
 	ApprovalVoteRequest { validator_index, block_hash }: ApprovalVoteRequest,
 ) -> SubsystemResult<Vec<Action>> {
+	let mut issue_approval_span = state
+		.spans
+		.get(&block_hash)
+		.map(|span| span.child("issue-approval"))
+		.unwrap_or_else(|| jaeger::Span::new(block_hash, "issue-approval"))
+		.with_trace_id(candidate_hash)
+		.with_string_tag("block-hash", format!("{:?}", block_hash))
+		.with_candidate(candidate_hash)
+		.with_validator_index(validator_index)
+		.with_stage(jaeger::Stage::ApprovalChecking);
+
 	let block_entry = match db.load_block_entry(&block_hash)? {
 		Some(b) => b,
 		None => {
@@ -2487,6 +2610,7 @@ async fn issue_approval<Context>(
 		},
 		Some(idx) => idx,
 	};
+	issue_approval_span.add_int_tag("candidate_index", candidate_index as i64);

 	let session_info = match state.session_info(block_entry.session()) {
 		Some(s) => s,
@@ -149,6 +149,7 @@ pub enum Stage {
 	AvailabilityRecovery = 6,
 	BitfieldDistribution = 7,
 	ApprovalChecking = 8,
+	ApprovalDistribution = 9,
 	// Expand as needed, numbers should be ascending according to the stage
 	// through the inclusion pipeline, or according to the descriptions
 	// in [the path of a para chain block]
@@ -283,6 +284,13 @@ impl Span {
 		}
 	}

+	/// Attach a 'traceID' tag set to the decimal representation of the candidate hash.
+	#[inline(always)]
+	pub fn with_trace_id(mut self, candidate_hash: CandidateHash) -> Self {
+		self.add_string_tag("traceID", hash_to_trace_identifier(candidate_hash.0));
+		self
+	}
+
 	#[inline(always)]
 	pub fn with_string_tag<V: ToString>(mut self, tag: &'static str, val: V) -> Self {
 		self.add_string_tag::<V>(tag, val);
@@ -10,6 +10,7 @@ polkadot-node-network-protocol = { path = "../protocol" }
 polkadot-node-primitives = { path = "../../primitives" }
 polkadot-node-subsystem = { path = "../../subsystem" }
 polkadot-primitives = { path = "../../../primitives" }
+polkadot-node-jaeger = { path = "../../jaeger" }
 rand = "0.8"

 futures = "0.3.21"
@@ -21,6 +21,7 @@
 #![warn(missing_docs)]

 use futures::{channel::oneshot, FutureExt as _};
+use polkadot_node_jaeger as jaeger;
 use polkadot_node_network_protocol::{
 	self as net_protocol,
 	grid_topology::{RandomRouting, RequiredRouting, SessionGridTopologies, SessionGridTopology},
@@ -35,7 +36,7 @@ use polkadot_node_subsystem::{
 		ApprovalCheckResult, ApprovalDistributionMessage, ApprovalVotingMessage,
 		AssignmentCheckResult, NetworkBridgeEvent, NetworkBridgeTxMessage,
 	},
-	overseer, ActiveLeavesUpdate, FromOrchestra, OverseerSignal, SpawnedSubsystem, SubsystemError,
+	overseer, FromOrchestra, OverseerSignal, SpawnedSubsystem, SubsystemError,
 };
 use polkadot_primitives::{
 	BlockNumber, CandidateIndex, Hash, SessionIndex, ValidatorIndex, ValidatorSignature,
@@ -180,6 +181,9 @@ struct State {

 	/// Config for aggression.
 	aggression_config: AggressionConfig,
+
+	/// HashMap from active leaves to spans
+	spans: HashMap<Hash, jaeger::PerLeafSpan>,
 }

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -390,9 +394,18 @@ impl State {
 	) {
 		let mut new_hashes = HashSet::new();
 		for meta in &metas {
+			let mut span = self
+				.spans
+				.get(&meta.hash)
+				.map(|span| span.child(&"handle-new-blocks"))
+				.unwrap_or_else(|| jaeger::Span::new(meta.hash, &"handle-new-blocks"))
+				.with_string_tag("block-hash", format!("{:?}", meta.hash))
+				.with_stage(jaeger::Stage::ApprovalDistribution);
+
 			match self.blocks.entry(meta.hash) {
 				hash_map::Entry::Vacant(entry) => {
 					let candidates_count = meta.candidates.len();
+					span.add_uint_tag("candidates-count", candidates_count as u64);
 					let mut candidates = Vec::with_capacity(candidates_count);
 					candidates.resize_with(candidates_count, Default::default);

@@ -690,6 +703,7 @@ impl State {
 			if let Some(block_entry) = self.blocks.remove(relay_block) {
 				self.topologies.dec_session_refs(block_entry.session);
 			}
+			self.spans.remove(&relay_block);
 		});

 		// If a block was finalized, this means we may need to move our aggression
@@ -1230,6 +1244,14 @@ impl State {
 	) -> HashMap<ValidatorIndex, ValidatorSignature> {
 		let mut all_sigs = HashMap::new();
 		for (hash, index) in indices {
+			let _span = self
+				.spans
+				.get(&hash)
+				.map(|span| span.child("get-approval-signatures"))
+				.unwrap_or_else(|| jaeger::Span::new(&hash, "get-approval-signatures"))
+				.with_string_tag("block-hash", format!("{:?}", hash))
+				.with_stage(jaeger::Stage::ApprovalDistribution);
+
 			let block_entry = match self.blocks.get(&hash) {
 				None => {
 					gum::debug!(
@@ -1650,13 +1672,18 @@ impl ApprovalDistribution {
 			match message {
 				FromOrchestra::Communication { msg } =>
 					Self::handle_incoming(&mut ctx, state, msg, &self.metrics, rng).await,
-				FromOrchestra::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate {
-					..
-				})) => {
+				FromOrchestra::Signal(OverseerSignal::ActiveLeaves(update)) => {
 					gum::trace!(target: LOG_TARGET, "active leaves signal (ignored)");
 					// the relay chain blocks relevant to the approval subsystems
 					// are those that are available, but not finalized yet
-					// actived and deactivated heads hence are irrelevant to this subsystem
+					// actived and deactivated heads hence are irrelevant to this subsystem, other than
+					// for tracing purposes.
+					if let Some(activated) = update.activated {
+						let head = activated.hash;
+						let approval_distribution_span =
+							jaeger::PerLeafSpan::new(activated.span, "approval-distribution");
+						state.spans.insert(head, approval_distribution_span);
+					}
 				},
 				FromOrchestra::Signal(OverseerSignal::BlockFinalized(_hash, number)) => {
 					gum::trace!(target: LOG_TARGET, number = %number, "finalized signal");
@@ -1682,6 +1709,14 @@ impl ApprovalDistribution {
 				state.handle_new_blocks(ctx, metrics, metas, rng).await;
 			},
 			ApprovalDistributionMessage::DistributeAssignment(cert, candidate_index) => {
+				let _span = state
+					.spans
+					.get(&cert.block_hash)
+					.map(|span| span.child("import-and-distribute-assignment"))
+					.unwrap_or_else(|| jaeger::Span::new(&cert.block_hash, "distribute-assignment"))
+					.with_string_tag("block-hash", format!("{:?}", cert.block_hash))
+					.with_stage(jaeger::Stage::ApprovalDistribution);
+
 				gum::debug!(
 					target: LOG_TARGET,
 					"Distributing our assignment on candidate (block={}, index={})",
@@ -1701,6 +1736,14 @@ impl ApprovalDistribution {
 					.await;
 			},
 			ApprovalDistributionMessage::DistributeApproval(vote) => {
+				let _span = state
+					.spans
+					.get(&vote.block_hash)
+					.map(|span| span.child("import-and-distribute-approval"))
+					.unwrap_or_else(|| jaeger::Span::new(&vote.block_hash, "distribute-approval"))
+					.with_string_tag("block-hash", format!("{:?}", vote.block_hash))
+					.with_stage(jaeger::Stage::ApprovalDistribution);
+
 				gum::debug!(
 					target: LOG_TARGET,
 					"Distributing our approval vote on candidate (block={}, index={})",
@@ -20,9 +20,11 @@ use sp_keystore::KeystorePtr;

 use polkadot_node_network_protocol::request_response::{v1, IncomingRequestReceiver};
 use polkadot_node_subsystem::{
-	messages::AvailabilityDistributionMessage, overseer, FromOrchestra, OverseerSignal,
+	jaeger, messages::AvailabilityDistributionMessage, overseer, FromOrchestra, OverseerSignal,
 	SpawnedSubsystem, SubsystemError,
 };
+use polkadot_primitives::Hash;
+use std::collections::HashMap;

 /// Error and [`Result`] type for this subsystem.
 mod error;
@@ -91,6 +93,7 @@ impl AvailabilityDistributionSubsystem {
 	/// Start processing work as passed on from the Overseer.
 	async fn run<Context>(self, mut ctx: Context) -> std::result::Result<(), FatalError> {
 		let Self { mut runtime, recvs, metrics } = self;
+		let mut spans: HashMap<Hash, jaeger::PerLeafSpan> = HashMap::new();

 		let IncomingRequestReceivers { pov_req_receiver, chunk_req_receiver } = recvs;
 		let mut requester = Requester::new(metrics.clone()).fuse();
@@ -131,15 +134,24 @@ impl AvailabilityDistributionSubsystem {
 			};
 			match message {
 				FromOrchestra::Signal(OverseerSignal::ActiveLeaves(update)) => {
+					let cloned_leaf = match update.activated.clone() {
+						Some(activated) => activated,
+						None => continue,
+					};
+					let span =
+						jaeger::PerLeafSpan::new(cloned_leaf.span, "availability-distribution");
+					spans.insert(cloned_leaf.hash, span);
 					log_error(
 						requester
 							.get_mut()
-							.update_fetching_heads(&mut ctx, &mut runtime, update)
+							.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 							.await,
 						"Error in Requester::update_fetching_heads",
 					)?;
 				},
-				FromOrchestra::Signal(OverseerSignal::BlockFinalized(..)) => {},
+				FromOrchestra::Signal(OverseerSignal::BlockFinalized(hash, _)) => {
+					spans.remove(&hash);
+				},
 				FromOrchestra::Signal(OverseerSignal::Conclude) => return Ok(()),
 				FromOrchestra::Communication {
 					msg:
@@ -152,6 +164,15 @@ impl AvailabilityDistributionSubsystem {
 							tx,
 						},
 				} => {
+					let span = spans
+						.get(&relay_parent)
+						.map(|span| span.child("fetch-pov"))
+						.unwrap_or_else(|| jaeger::Span::new(&relay_parent, "fetch-pov"))
+						.with_trace_id(candidate_hash)
+						.with_candidate(candidate_hash)
+						.with_relay_parent(relay_parent)
+						.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 					log_error(
 						pov_requester::fetch_pov(
 							&mut ctx,
@@ -163,6 +184,7 @@ impl AvailabilityDistributionSubsystem {
 							pov_hash,
 							tx,
 							metrics.clone(),
+							&span,
 						)
 						.await,
 						"pov_requester::fetch_pov",
@@ -52,7 +52,18 @@ pub async fn fetch_pov<Context>(
 	pov_hash: Hash,
 	tx: oneshot::Sender<PoV>,
 	metrics: Metrics,
+	span: &jaeger::Span,
 ) -> Result<()> {
+	let _span = span
+		.child("fetch-pov")
+		.with_trace_id(candidate_hash)
+		.with_validator_index(from_validator)
+		.with_candidate(candidate_hash)
+		.with_para_id(para_id)
+		.with_relay_parent(parent)
+		.with_string_tag("pov-hash", format!("{:?}", pov_hash))
+		.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 	let info = &runtime.get_session_info(ctx.sender(), parent).await?.session_info;
 	let authority_id = info
 		.discovery_keys
@@ -71,13 +82,9 @@ pub async fn fetch_pov<Context>(
 	))
 	.await;

-	let span = jaeger::Span::new(candidate_hash, "fetch-pov")
-		.with_validator_index(from_validator)
-		.with_relay_parent(parent)
-		.with_para_id(para_id);
 	ctx.spawn(
 		"pov-fetcher",
-		fetch_pov_job(para_id, pov_hash, authority_id, pending_response.boxed(), span, tx, metrics)
+		fetch_pov_job(para_id, pov_hash, authority_id, pending_response.boxed(), tx, metrics)
 			.boxed(),
 	)
 	.map_err(|e| FatalError::SpawnTask(e))?;
@@ -90,11 +97,10 @@ async fn fetch_pov_job(
 	pov_hash: Hash,
 	authority_id: AuthorityDiscoveryId,
 	pending_response: BoxFuture<'static, std::result::Result<PoVFetchingResponse, RequestError>>,
-	span: jaeger::Span,
 	tx: oneshot::Sender<PoV>,
 	metrics: Metrics,
 ) {
-	if let Err(err) = do_fetch_pov(pov_hash, pending_response, span, tx, metrics).await {
+	if let Err(err) = do_fetch_pov(pov_hash, pending_response, tx, metrics).await {
 		gum::warn!(target: LOG_TARGET, ?err, ?para_id, ?pov_hash, ?authority_id, "fetch_pov_job");
 	}
 }
@@ -103,7 +109,6 @@ async fn fetch_pov_job(
 async fn do_fetch_pov(
 	pov_hash: Hash,
 	pending_response: BoxFuture<'static, std::result::Result<PoVFetchingResponse, RequestError>>,
-	_span: jaeger::Span,
 	tx: oneshot::Sender<PoV>,
 	metrics: Metrics,
 ) -> Result<()> {
@@ -182,6 +187,7 @@ mod tests {
 				pov_hash,
 				tx,
 				Metrics::new_dummy(),
+				&jaeger::Span::Disabled,
 			)
 			.await
 			.expect("Should succeed");
@@ -140,7 +140,18 @@ impl FetchTaskConfig {
 		sender: mpsc::Sender<FromFetchTask>,
 		metrics: Metrics,
 		session_info: &SessionInfo,
+		span: jaeger::Span,
 	) -> Self {
+		let span = span
+			.child("fetch-task-config")
+			.with_trace_id(core.candidate_hash)
+			.with_string_tag("leaf", format!("{:?}", leaf))
+			.with_validator_index(session_info.our_index)
+			.with_uint_tag("group-index", core.group_responsible.0 as u64)
+			.with_relay_parent(core.candidate_descriptor.relay_parent)
+			.with_string_tag("pov-hash", format!("{:?}", core.candidate_descriptor.pov_hash))
+			.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 		let live_in = vec![leaf].into_iter().collect();

 		// Don't run tasks for our backing group:
@@ -148,9 +159,6 @@ impl FetchTaskConfig {
 			return FetchTaskConfig { live_in, prepared_running: None }
 		}

-		let span = jaeger::Span::new(core.candidate_hash, "availability-distribution")
-			.with_stage(jaeger::Stage::AvailabilityDistribution);
-
 		let prepared_running = RunningTask {
 			session_index: session_info.session_index,
 			group_index: core.group_responsible,
@@ -251,20 +259,18 @@ impl RunningTask {
 		let mut bad_validators = Vec::new();
 		let mut succeeded = false;
 		let mut count: u32 = 0;
-		let mut _span = self
-			.span
-			.child("fetch-task")
-			.with_chunk_index(self.request.index.0)
-			.with_relay_parent(self.relay_parent);
+		let mut span = self.span.child("run-fetch-chunk-task").with_relay_parent(self.relay_parent);
 		// Try validators in reverse order:
 		while let Some(validator) = self.group.pop() {
-			let _try_span = _span.child("try");
 			// Report retries:
 			if count > 0 {
 				self.metrics.on_retry();
 			}
 			count += 1;
-
+			let _chunk_fetch_span = span
+				.child("fetch-chunk-request")
+				.with_chunk_index(self.request.index.0)
+				.with_stage(jaeger::Stage::AvailabilityDistribution);
 			// Send request:
 			let resp = match self.do_request(&validator).await {
 				Ok(resp) => resp,
@@ -281,6 +287,12 @@ impl RunningTask {
 					continue
 				},
 			};
+			// We drop the span here, so that the span is not active while we recombine the chunk.
+			drop(_chunk_fetch_span);
+			let _chunk_recombine_span = span
+				.child("recombine-chunk")
+				.with_chunk_index(self.request.index.0)
+				.with_stage(jaeger::Stage::AvailabilityDistribution);
 			let chunk = match resp {
 				ChunkFetchingResponse::Chunk(resp) => resp.recombine_into_chunk(&self.request),
 				ChunkFetchingResponse::NoSuchChunk => {
@@ -298,6 +310,12 @@ impl RunningTask {
 					continue
 				},
 			};
+			// We drop the span so that the span is not active whilst we validate and store the chunk.
+			drop(_chunk_recombine_span);
+			let _chunk_validate_and_store_span = span
+				.child("validate-and-store-chunk")
+				.with_chunk_index(self.request.index.0)
+				.with_stage(jaeger::Stage::AvailabilityDistribution);

 			// Data genuine?
 			if !self.validate_chunk(&validator, &chunk) {
@@ -308,10 +326,9 @@ impl RunningTask {
 			// Ok, let's store it and be happy:
 			self.store_chunk(chunk).await;
 			succeeded = true;
-			_span.add_string_tag("success", "true");
 			break
 		}
-		_span.add_int_tag("tries", count as _);
+		span.add_int_tag("tries", count as _);
 		if succeeded {
 			self.metrics.on_fetch(SUCCEEDED);
 			self.conclude(bad_validators).await;
@@ -33,6 +33,7 @@ use futures::{
 };

 use polkadot_node_subsystem::{
+	jaeger,
 	messages::{ChainApiMessage, RuntimeApiMessage},
 	overseer, ActivatedLeaf, ActiveLeavesUpdate, LeafStatus,
 };
@@ -100,14 +101,22 @@ impl Requester {
 		ctx: &mut Context,
 		runtime: &mut RuntimeInfo,
 		update: ActiveLeavesUpdate,
+		spans: &HashMap<Hash, jaeger::PerLeafSpan>,
 	) -> Result<()> {
 		gum::trace!(target: LOG_TARGET, ?update, "Update fetching heads");
 		let ActiveLeavesUpdate { activated, deactivated } = update;
 		// Stale leaves happen after a reversion - we don't want to re-run availability there.
 		if let Some(leaf) = activated.filter(|leaf| leaf.status == LeafStatus::Fresh) {
+			let span = spans
+				.get(&leaf.hash)
+				.map(|span| span.child("update-fetching-heads"))
+				.unwrap_or_else(|| jaeger::Span::new(&leaf.hash, "update-fetching-heads"))
+				.with_string_tag("leaf", format!("{:?}", leaf.hash))
+				.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 			// Order important! We need to handle activated, prior to deactivated, otherwise we might
 			// cancel still needed jobs.
-			self.start_requesting_chunks(ctx, runtime, leaf).await?;
+			self.start_requesting_chunks(ctx, runtime, leaf, &span).await?;
 		}

 		self.stop_requesting_chunks(deactivated.into_iter());
@@ -123,7 +132,13 @@ impl Requester {
 		ctx: &mut Context,
 		runtime: &mut RuntimeInfo,
 		new_head: ActivatedLeaf,
+		span: &jaeger::Span,
 	) -> Result<()> {
+		let mut span = span
+			.child("request-chunks-new-head")
+			.with_string_tag("leaf", format!("{:?}", new_head.hash))
+			.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 		let sender = &mut ctx.sender().clone();
 		let ActivatedLeaf { hash: leaf, .. } = new_head;
 		let (leaf_session_index, ancestors_in_session) = get_block_ancestors_in_same_session(
@@ -133,8 +148,15 @@ impl Requester {
 			Self::LEAF_ANCESTRY_LEN_WITHIN_SESSION,
 		)
 		.await?;
+		span.add_uint_tag("ancestors-in-session", ancestors_in_session.len() as u64);
+
 		// Also spawn or bump tasks for candidates in ancestry in the same session.
 		for hash in std::iter::once(leaf).chain(ancestors_in_session) {
+			let span = span
+				.child("request-chunks-ancestor")
+				.with_string_tag("leaf", format!("{:?}", hash.clone()))
+				.with_stage(jaeger::Stage::AvailabilityDistribution);
+
 			let cores = get_occupied_cores(sender, hash).await?;
 			gum::trace!(
 				target: LOG_TARGET,
@@ -148,7 +170,7 @@ impl Requester {
 			// The next time the subsystem receives leaf update, some of spawned task will be bumped
 			// to be live in fresh relay parent, while some might get dropped due to the current leaf
 			// being deactivated.
-			self.add_cores(ctx, runtime, leaf, leaf_session_index, cores).await?;
+			self.add_cores(ctx, runtime, leaf, leaf_session_index, cores, span).await?;
 		}

 		Ok(())
@@ -178,15 +200,24 @@ impl Requester {
 		leaf: Hash,
 		leaf_session_index: SessionIndex,
 		cores: impl IntoIterator<Item = OccupiedCore>,
+		span: jaeger::Span,
 	) -> Result<()> {
 		for core in cores {
+			let mut span = span
+				.child("check-fetch-candidate")
+				.with_trace_id(core.candidate_hash)
+				.with_string_tag("leaf", format!("{:?}", leaf))
+				.with_candidate(core.candidate_hash)
+				.with_stage(jaeger::Stage::AvailabilityDistribution);
 			match self.fetches.entry(core.candidate_hash) {
 				Entry::Occupied(mut e) =>
 				// Just book keeping - we are already requesting that chunk:
 				{
+					span.add_string_tag("already-requested-chunk", "true");
 					e.get_mut().add_leaf(leaf);
 				},
 				Entry::Vacant(e) => {
+					span.add_string_tag("already-requested-chunk", "false");
 					let tx = self.tx.clone();
 					let metrics = self.metrics.clone();

@@ -201,7 +232,7 @@ impl Requester {
 							// be fetchable by the state trie.
 							leaf,
 							leaf_session_index,
-							|info| FetchTaskConfig::new(leaf, &core, tx, metrics, info),
+							|info| FetchTaskConfig::new(leaf, &core, tx, metrics, info, span),
 						)
 						.await
 						.map_err(|err| {
@@ -14,6 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

+use std::collections::HashMap;
+
 use std::{future::Future, sync::Arc};

 use futures::FutureExt;
@@ -196,7 +198,7 @@ fn check_ancestry_lookup_in_same_session() {

 	test_harness(test_state.clone(), |mut ctx| async move {
 		let chain = &test_state.relay_chain;
-
+		let spans: HashMap<Hash, jaeger::PerLeafSpan> = HashMap::new();
 		let block_number = 1;
 		let update = ActiveLeavesUpdate {
 			activated: Some(ActivatedLeaf {
@@ -209,7 +211,7 @@ fn check_ancestry_lookup_in_same_session() {
 		};

 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -229,7 +231,7 @@ fn check_ancestry_lookup_in_same_session() {
 		};

 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -255,7 +257,7 @@ fn check_ancestry_lookup_in_same_session() {
 			deactivated: vec![chain[1], chain[2]].into(),
 		};
 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -283,7 +285,7 @@ fn check_ancestry_lookup_in_different_sessions() {

 	test_harness(test_state.clone(), |mut ctx| async move {
 		let chain = &test_state.relay_chain;
-
+		let spans: HashMap<Hash, jaeger::PerLeafSpan> = HashMap::new();
 		let block_number = 3;
 		let update = ActiveLeavesUpdate {
 			activated: Some(ActivatedLeaf {
@@ -296,7 +298,7 @@ fn check_ancestry_lookup_in_different_sessions() {
 		};

 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -314,7 +316,7 @@ fn check_ancestry_lookup_in_different_sessions() {
 		};

 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -332,7 +334,7 @@ fn check_ancestry_lookup_in_different_sessions() {
 		};

 		requester
-			.update_fetching_heads(&mut ctx, &mut runtime, update)
+			.update_fetching_heads(&mut ctx, &mut runtime, update, &spans)
 			.await
 			.expect("Leaf processing failed");
 		let fetch_tasks = &requester.fetches;
@@ -186,7 +186,10 @@ where
 {
 	let span = jaeger::Span::new(req.payload.candidate_hash, "answer-chunk-request");

-	let _child_span = span.child("answer-chunk-request").with_chunk_index(req.payload.index.0);
+	let _child_span = span
+		.child("answer-chunk-request")
+		.with_trace_id(req.payload.candidate_hash)
+		.with_chunk_index(req.payload.index.0);

 	let chunk = query_chunk(sender, req.payload.candidate_hash, req.payload.index).await?;