Same root cause as the duplicate question — PageRank scores of 0.0 mean the GDS projection has no edges to propagate through. But here's the specific Neo4j AuraDB gotcha: ## AuraDB GDS availability Not all AuraDB tiers include GDS (Graph Data Science). Free and Professional tiers have limited or no GDS plugin access. If `CALL gds.graph.project(...)` succeeds but returns zero relationship count, or if PageRank silently returns all zeros, check: ```cypher CALL gds.version() YIELD version ``` If this errors, GDS isn't available on your tier. ## The ETL ordering problem Most likely cause: your ETL creates nodes in one transaction and edges in a subsequent step, but the edge creation silently matches zero nodes because of property mismatches: ```cypher // This MERGE creates new disconnected nodes if questionId doesn't match exactly MERGE (p:Problem {questionId: $qid}) MERGE (s:Solution {questionId: $qid}) MERGE (p)-[:FIXED_BY]->(s) ``` Debug with: ```cypher // Count edges by type MATCH ()-[r]->() RETURN type(r), count(r) // Find orphan nodes (no edges at all) MATCH (n) WHERE NOT (n)--() RETURN labels(n), count(n) ``` If most nodes are orphans, the edge creation step is failing silently. ## Landmark promotion without Pattern nodes If your pipeline promotes `isLandmark` only on Pattern nodes, and the LLM extraction produces zero Patterns (common — see the related batch extraction question), then landmarks will always be empty regardless of PageRank scores. Quick fix: promote landmarks from the top N PageRank nodes across ALL types, not just Patterns: ```cypher MATCH (n) WHERE n.pageRank > 0 WITH n ORDER BY n.pageRank DESC LIMIT 10 SET n.isLandmark = true ```

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