Reduced logging noise from deleteExpiredTransactions but increased detection & logging on "serilization failures" from HSQLDB

src/main/java/org/qortal/controller/Controller.java

@@ -806,7 +806,10 @@ public class Controller extends Thread {
 
 			repository.saveChanges();
 		} catch (DataException e) {
-			LOGGER.error("Repository issue while deleting expired unconfirmed transactions", e);
+			if (RepositoryManager.isDeadlockRelated(e))
+				LOGGER.info("Couldn't delete some expired, unconfirmed transactions this round");
+			else
+				LOGGER.error("Repository issue while deleting expired unconfirmed transactions", e);
 		}
 	}
 

src/main/java/org/qortal/repository/RepositoryFactory.java

@@ -1,5 +1,7 @@
 package org.qortal.repository;
 
+import java.sql.SQLException;
+
 public interface RepositoryFactory {
 
 	public boolean wasPristineAtOpen();
@@ -12,4 +14,7 @@ public interface RepositoryFactory {
 
 	public void close() throws DataException;
 
+	// Not ideal place for this but implementating class will know the answer without having to open a new DB session
+	public boolean isDeadlockException(SQLException e);
+
 }

src/main/java/org/qortal/repository/RepositoryManager.java

@@ -1,5 +1,7 @@
 package org.qortal.repository;
 
+import java.sql.SQLException;
+
 public abstract class RepositoryManager {
 
 	private static RepositoryFactory repositoryFactory = null;
@@ -69,4 +71,10 @@ public abstract class RepositoryManager {
 		repositoryFactory = oldRepositoryFactory.reopen();
 	}
 
+	public static boolean isDeadlockRelated(Throwable e) {
+		Throwable cause = e.getCause();
+
+		return SQLException.class.isInstance(cause) && repositoryFactory.isDeadlockException((SQLException) cause);
+	}
+
 }

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

@@ -59,6 +59,9 @@ public class HSQLDBRepository implements Repository {
 
 	private static final Object CHECKPOINT_LOCK = new Object();
 
+	// "serialization failure"
+	private static final Integer DEADLOCK_ERROR_CODE = Integer.valueOf(-4861);
+
 	protected Connection connection;
 	protected final Deque<Savepoint> savepoints = new ArrayDeque<>(3);
 	protected boolean debugState = false;
@@ -708,7 +711,16 @@ public class HSQLDBRepository implements Repository {
 
 		long beforeQuery = this.slowQueryThreshold == null ? 0 : System.currentTimeMillis();
 
-		int[] updateCounts = preparedStatement.executeBatch();
+		int[] updateCounts = null;
+		try {
+			updateCounts = preparedStatement.executeBatch();
+		} catch (SQLException e) {
+			if (isDeadlockException(e))
+				// We want more info on what other DB sessions are doing to cause this
+				examineException(e);
+
+			throw e;
+		}
 
 		if (this.slowQueryThreshold != null) {
 			long queryTime = System.currentTimeMillis() - beforeQuery;
@@ -1000,4 +1012,8 @@ public class HSQLDBRepository implements Repository {
 		return Crypto.toAddress(publicKey);
 	}
 
+	/*package*/ static boolean isDeadlockException(SQLException e) {
+		return DEADLOCK_ERROR_CODE.equals(e.getErrorCode());
+	}
+
 }

src/main/java/org/qortal/repository/hsqldb/HSQLDBRepositoryFactory.java

@@ -148,4 +148,9 @@ public class HSQLDBRepositoryFactory implements RepositoryFactory {
 		}
 	}
 
+	@Override
+	public boolean isDeadlockException(SQLException e) {
+		return HSQLDBRepository.isDeadlockException(e);
+	}
+
 }