Add callstack when logging slow repository queries. Blockchain.validate() improvement

src/main/java/org/qora/block/BlockChain.java

@@ -28,7 +28,6 @@ import org.eclipse.persistence.exceptions.XMLMarshalException;
 import org.eclipse.persistence.jaxb.JAXBContextFactory;
 import org.eclipse.persistence.jaxb.UnmarshallerProperties;
 import org.qora.controller.Controller;
-import org.qora.controller.Synchronizer.SynchronizationResult;
 import org.qora.data.block.BlockData;
 import org.qora.network.Network;
 import org.qora.repository.BlockRepository;
@@ -487,6 +486,9 @@ public class BlockChain {
 			BlockData parentBlockData = parentBlock.getBlockData();
 
 			while (true) {
+				// No need to maintain transaction state while ploughing through the entire chain
+				repository.discardChanges();
+
 				BlockData childBlockData = parentBlock.getChild();
 				if (childBlockData == null)
 					break;

src/main/java/org/qora/repository/hsqldb/HSQLDBRepository.java

@@ -394,7 +394,7 @@ public class HSQLDBRepository implements Repository {
 
 		long queryTime = System.currentTimeMillis() - beforeQuery;
 		if (this.slowQueryThreshold != null && queryTime > this.slowQueryThreshold) {
-			LOGGER.info(String.format("HSQLDB query took %d ms: %s", queryTime, sql));
+			LOGGER.info(String.format("HSQLDB query took %d ms: %s", queryTime, sql), new SQLException("slow query"));
 
 			logStatements();
 		}