Another attempt to prevent "serialization failure" during trimming

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

@@ -90,7 +90,10 @@ public interface ATRepository {
 	/** Returns height of first trimmable AT state. */
 	public int getAtTrimHeight() throws DataException;
 
-	/** Sets new base height for AT state trimming. */
+	/** Sets new base height for AT state trimming.
+	 * <p>
+	 * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+	 */
 	public void setAtTrimHeight(int trimHeight) throws DataException;
 
 	/** Hook to allow repository to prepare/cache info for AT state trimming. */

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

@@ -146,7 +146,10 @@ public interface BlockRepository {
 	/** Returns height of first trimmable online accounts signatures. */
 	public int getOnlineAccountsSignaturesTrimHeight() throws DataException;
 
-	/** Sets new base height for trimming online accounts signatures. */
+	/** Sets new base height for trimming online accounts signatures.
+	 * <p>
+	 * NOTE: performs implicit <tt>repository.saveChanges()</tt>.
+	 */
 	public void setOnlineAccountsSignaturesTrimHeight(int trimHeight) throws DataException;
 
 	/**

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

@@ -425,6 +425,7 @@ public class HSQLDBATRepository implements ATRepository {
 
 			try {
 				this.repository.executeCheckedUpdate(updateSql, trimHeight);
+				this.repository.saveChanges();
 			} catch (SQLException e) {
 				repository.examineException(e);
 				throw new DataException("Unable to set AT state trim height in repository", e);

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

@@ -484,6 +484,7 @@ public class HSQLDBBlockRepository implements BlockRepository {
 
 			try {
 				this.repository.executeCheckedUpdate(updateSql, trimHeight);
+				this.repository.saveChanges();
 			} catch (SQLException e) {
 				repository.examineException(e);
 				throw new DataException("Unable to set online accounts signatures trim height in repository", e);