HHH-15728 Improve query cache key hash code to reduce collisions

hibernate-core/src/main/java/org/hibernate/cache/spi/QueryKey.java

@@ -105,15 +105,12 @@ public class QueryKey implements Serializable {
 	private int generateHashCode() {
 		int result = 13;
 		result = 37 * result + sqlQueryString.hashCode();
-		result = 37 * result + ( firstRow==null ? 0 : firstRow );
+		// Don't include the firstRow and maxRows in the hash as these values are rarely useful for query caching
-		result = 37 * result + ( maxRows==null ? 0 : maxRows );
+//		result = 37 * result + ( firstRow==null ? 0 : firstRow );
+//		result = 37 * result + ( maxRows==null ? 0 : maxRows );
 		result = 37 * result + ( tenantIdentifier==null ? 0 : tenantIdentifier.hashCode() );
-		// the collections are too complicated to incorporate into the hashcode.  but they really
+		result = 37 * result + parameterBindingsMemento.hashCode();
-		// aren't needed in the hashcode calculation - they are handled in `#equals` and the calculation
+		result = 37 * result + ( enabledFilterNames == null ? 0 : enabledFilterNames.hashCode() );
-		// without them is a good hashing code.
-		//
-		// todo (6.0) : maybe even just base it on `sqlQueryString`?
-
 		return result;
 	}
 

hibernate-core/src/main/java/org/hibernate/query/internal/QueryParameterBindingsImpl.java

@@ -186,7 +186,7 @@ public class QueryParameterBindingsImpl implements QueryParameterBindings {
 							? javaType.extractHashCode( bindValue )
 							: 0;
 
-					hashCode = 31 * hashCode + valueHashCode;
+					hashCode = 37 * hashCode + valueHashCode;
 				}
 			}
 			else {
@@ -199,7 +199,7 @@ public class QueryParameterBindingsImpl implements QueryParameterBindings {
 						? javaType.extractHashCode( bindValue )
 						: 0;
 
-				hashCode = 31 * hashCode + valueHashCode;
+				hashCode = 37 * hashCode + valueHashCode;
 			}
 		}