Stop sibling re-enqueue from flooding mapping logs

The tracker-mapping worker re-arms same-banner siblings after a pattern
resolves a vendor. Its predicate only excluded promoted siblings
(third_party_id IS NULL), but since org-party auto-creation was dropped a
pattern can resolve a common third party yet never gain an org
third_party_id. Those siblings, and terminal first-party ones, stayed
eligible forever, so every cascade step re-enqueued and reprocessed them,
amplifying Process runs to O(N^2) per banner. The deadlock fix in the
last release removed the rollbacks that had accidentally throttled the
cascade, so the latent amplification surfaced as an INFO-log flood.

Tighten the re-enqueue to skip siblings already linked to a catalog row
that carries a common third party or marked FIRST_PARTY, dropping
per-banner reprocessing back to O(N). Also demote the two per-run handler
logs ("mapped tracker pattern", "re-enqueued unmapped sibling tracker
patterns") to Debug so routine processing no longer logs at INFO.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/cookiebanner/tracker_mapping_worker.go

@@ -341,7 +341,7 @@ func (h *trackerMappingHandler) Process(ctx context.Context, tp coredata.Tracker
 				return fmt.Errorf("cannot update tracker pattern mapping: %w", err)
 			}
 
-			h.logger.InfoCtx(
+			h.logger.DebugCtx(
 				ctx,
 				"mapped tracker pattern",
 				log.String("pattern", tp.Pattern),
@@ -539,7 +539,7 @@ func (h *trackerMappingHandler) reenqueueUnmappedSiblings(
 	}
 
 	if count > 0 {
-		h.logger.InfoCtx(
+		h.logger.DebugCtx(
 			ctx,
 			"re-enqueued unmapped sibling tracker patterns",
 			log.String("tracker_pattern_id", tp.ID.String()),

pkg/coredata/tracker_pattern.go

@@ -1269,11 +1269,18 @@ WHERE id = @id
 // siblings that were processed earlier and left unmatched can now be
 // re-evaluated against it.
 //
-// Only unpromoted (third_party_id IS NULL), not-already-queued
+// Only siblings still genuinely unresolved are touched: not promoted to
-// (mapping_requested_at IS NULL), non-extension siblings are touched, so
+// an org party (third_party_id IS NULL), not already linked to a catalog
-// a fully mapped banner re-enqueues nothing. detected_trackers is used
+// row that carries a common third party, and not marked FIRST_PARTY
-// only as a filtering subquery. Returns the number of siblings
+// (a terminal verdict). third_party_id IS NULL alone is no longer a
-// re-enqueued.
+// sufficient guard: since org-party auto-creation was dropped a pattern
+// can resolve a common third party yet stay third_party_id IS NULL, and
+// re-enqueueing those (or first-party siblings) on every cascade step is
+// what amplified reprocessing to O(N^2) per banner. The siblings must
+// also be not-already-queued (mapping_requested_at IS NULL) and
+// non-extension. A fully mapped banner re-enqueues nothing.
+// common_tracker_patterns and detected_trackers are used only as
+// filtering subqueries. Returns the number of siblings re-enqueued.
 func (tps *TrackerPatterns) RequestMappingForUnmappedSiblings(
 	ctx context.Context,
 	tx pg.Tx,
@@ -1306,6 +1313,15 @@ WHERE id IN (
 		AND third_party_id IS NULL
 		AND mapping_requested_at IS NULL
 		AND (source IS NULL OR source != @extension_source)
+		AND NOT EXISTS (
+			SELECT 1
+			FROM common_tracker_patterns ctp
+			WHERE ctp.id = tracker_patterns.common_tracker_pattern_id
+				AND (
+					ctp.common_third_party_id IS NOT NULL
+					OR ctp.attribution = 'FIRST_PARTY'
+				)
+		)
 		AND id IN (
 			SELECT DISTINCT tracker_pattern_id
 			FROM detected_trackers