simonbence commented on code in PR #8152: URL: https://github.com/apache/nifi/pull/8152#discussion_r1447199207
########## nifi-nar-bundles/nifi-questdb-bundle/nifi-questdb/src/main/java/org/apache/nifi/questdb/embedded/LockedClient.java: ########## @@ -0,0 +1,105 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.nifi.questdb.embedded; + +import org.apache.nifi.questdb.Client; +import org.apache.nifi.questdb.DatabaseException; +import org.apache.nifi.questdb.InsertRowDataSource; +import org.apache.nifi.questdb.QueryResultProcessor; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.concurrent.Callable; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.Lock; + +final class LockedClient implements Client { Review Comment: This lock server different purposes than the database's internal lock. Due to the embedded nature of the database, the maintenance of it is a responsibility taken care by the `EmbeddedDatabaseManager`. This comes with time periods where the database is tampered with (kind of under maintenance) when we do not want to interact with the database. This is prevented and encapsulated by the `LockedClient`. Together with the retry, this should make shorter outages (recreating database) unnoticable for clients. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@nifi.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
