wip

Author: hmottestad

core/sail/lmdb/src/main/java/org/eclipse/rdf4j/sail/lmdb/LmdbEvaluationStatistics.java

@@ -12,8 +12,8 @@
 package org.eclipse.rdf4j.sail.lmdb;
 
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.eclipse.rdf4j.model.IRI;
 import org.eclipse.rdf4j.model.Resource;
@@ -31,15 +31,19 @@
 class LmdbEvaluationStatistics extends EvaluationStatistics {
 
 	private static final Logger log = LoggerFactory.getLogger(LmdbEvaluationStatistics.class);
+	private static final int SHARED_CACHE_MAX_ENTRIES = 262_144;
+	private static final Map<SharedCardinalityKey, Double> sharedCardinalityCache = new ConcurrentHashMap<>();
 
 	private final ValueStore valueStore;
 
 	private final TripleStore tripleStore;
-	private final Map<CardinalityKey, Double> cardinalityCache = new HashMap<>();
+	private final int tripleStoreIdentity;
+	private final Map<CardinalityKey, Double> cardinalityCache = new ConcurrentHashMap<>();
 
 	public LmdbEvaluationStatistics(ValueStore valueStore, TripleStore tripleStore) {
 		this.valueStore = valueStore;
 		this.tripleStore = tripleStore;
+		this.tripleStoreIdentity = System.identityHashCode(tripleStore);
 	}
 
 	@Override
@@ -116,17 +120,31 @@ private double cardinality(Resource subj, IRI pred, Value obj, Resource context)
 			}
 		}
 
-		return tripleStore.cardinality(subjID, predID, objID, contextID);
-
-//		CardinalityKey key = new CardinalityKey(subjID, predID, objID, contextID);
-//		Double cached = cardinalityCache.get(key);
-//		if (cached != null) {
-//			return cached;
-//		}
-//
-//		double cardinality = tripleStore.cardinality(subjID, predID, objID, contextID);
-//		cardinalityCache.put(key, cardinality);
-//		return cardinality;
+		CardinalityKey key = new CardinalityKey(subjID, predID, objID, contextID);
+		Double cached = cardinalityCache.get(key);
+		if (cached != null) {
+			return cached;
+		}
+
+		long revisionId = valueStore.getRevision().getRevisionId();
+		SharedCardinalityKey sharedKey = new SharedCardinalityKey(tripleStoreIdentity, revisionId, key);
+		Double sharedCached = sharedCardinalityCache.get(sharedKey);
+		if (sharedCached != null) {
+			cardinalityCache.put(key, sharedCached);
+			return sharedCached;
+		}
+
+		double cardinality = tripleStore.cardinality(subjID, predID, objID, contextID);
+		cardinalityCache.put(key, cardinality);
+		cacheSharedCardinality(sharedKey, cardinality);
+		return cardinality;
+	}
+
+	private static void cacheSharedCardinality(SharedCardinalityKey key, double cardinality) {
+		if (sharedCardinalityCache.size() >= SHARED_CACHE_MAX_ENTRIES) {
+			sharedCardinalityCache.clear();
+		}
+		sharedCardinalityCache.put(key, cardinality);
 	}
 
 	private static final class CardinalityKey {
@@ -166,4 +184,52 @@ public int hashCode() {
 			return result;
 		}
 	}
+
+	private static final class SharedCardinalityKey {
+		private final int tripleStoreIdentity;
+		private final long revisionId;
+		private final long subjID;
+		private final long predID;
+		private final long objID;
+		private final long contextID;
+		private final int hashCode;
+
+		private SharedCardinalityKey(int tripleStoreIdentity, long revisionId, CardinalityKey cardinalityKey) {
+			this.tripleStoreIdentity = tripleStoreIdentity;
+			this.revisionId = revisionId;
+			this.subjID = cardinalityKey.subjID;
+			this.predID = cardinalityKey.predID;
+			this.objID = cardinalityKey.objID;
+			this.contextID = cardinalityKey.contextID;
+			int hash = Integer.hashCode(tripleStoreIdentity);
+			hash = 31 * hash + Long.hashCode(revisionId);
+			hash = 31 * hash + Long.hashCode(subjID);
+			hash = 31 * hash + Long.hashCode(predID);
+			hash = 31 * hash + Long.hashCode(objID);
+			hash = 31 * hash + Long.hashCode(contextID);
+			this.hashCode = hash;
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (!(obj instanceof SharedCardinalityKey)) {
+				return false;
+			}
+			SharedCardinalityKey other = (SharedCardinalityKey) obj;
+			return tripleStoreIdentity == other.tripleStoreIdentity
+					&& revisionId == other.revisionId
+					&& subjID == other.subjID
+					&& predID == other.predID
+					&& objID == other.objID
+					&& contextID == other.contextID;
+		}
+
+		@Override
+		public int hashCode() {
+			return hashCode;
+		}
+	}
 }

core/sail/lmdb/src/test/java/org/eclipse/rdf4j/sail/lmdb/benchmark/ThemeQueryBenchmark.java

@@ -262,6 +262,7 @@ private void captureQueryPlanSnapshot() throws IOException {
 				.addReflectiveGetter("lmdbStore.writable", store, "isWritable")
 				.addReflectiveGetter("lmdbConfig.tripleIndexes", storeConfig, "getTripleIndexes")
 				.addReflectiveGetter("lmdbConfig.forceSync", storeConfig, "getForceSync")
+				.addReflectiveGetter("lmdbConfig.pageCardinalityEstimator", storeConfig, "getPageCardinalityEstimator")
 				.addReflectiveField("lmdbConfig.autoGrow", storeConfig, "autoGrow")
 				.addReflectiveGetter("lmdbConfig.valueDbSize", storeConfig, "getValueDBSize")
 				.addReflectiveGetter("lmdbConfig.tripleDbSize", storeConfig, "getTripleDBSize");