zachjsh commented on code in PR #13165: URL: https://github.com/apache/druid/pull/13165#discussion_r1007185076
########## extensions-core/druid-catalog/src/main/java/org/apache/druid/catalog/storage/sql/CatalogManager.java: ########## @@ -0,0 +1,167 @@ +/* + * 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.druid.catalog.storage.sql; + +import org.apache.druid.catalog.model.TableId; +import org.apache.druid.catalog.model.TableMetadata; +import org.apache.druid.catalog.model.TableSpec; + +import javax.annotation.Nullable; + +import java.util.List; +import java.util.function.Function; + +/** + * Manages catalog data. Used in Coordinator, which will be in either + * an leader or standby state. The Coordinator calls the {@link #start()} + * method when it becomes the leader, and calls {@link #stop()} when + * it loses leadership, or shuts down. + * + * Performs detailed CRUD operations on the catalog tables table. + * Higher-level operations appear elsewhere. + */ +public interface CatalogManager +{ + /** + * Thrown with an "optimistic lock" fails: the version of a + * catalog object being updated is not the same as that of + * the expected version. + */ + class OutOfDateException extends Exception + { + public OutOfDateException(String msg) + { + super(msg); + } + } + + class NotFoundException extends Exception + { + public NotFoundException(String msg) + { + super(msg); + } + } + + /** + * Indicates an attempt to insert a duplicate key into a table. + * This could indicate a logic error, or a race condition. It is + * generally not retryable: it us unrealistic to expect the other + * thread to helpfully delete the record it just added. + */ + class DuplicateKeyException extends Exception + { + public DuplicateKeyException(String msg, Exception e) + { + super(msg, e); + } + } + + interface Listener + { + void added(TableMetadata table); + void updated(TableMetadata table); + void deleted(TableId id); + } + + void start(); + + + void register(Listener listener); + void createTableDefnTable(); + + /** + * Create a table entry. + * + * @return the version of the newly created table. Call + * {@link TableMetadata#asUpdate(long)} if you want a new + * {@link TableMetadata} with the new version. + * @throws {@link DuplicateKeyException} if the row is a duplicate + * (schema, name) pair. This generally indicates a code error, + * or since our code is perfect, a race condition or a DB + * update outside of Druid. In any event, the error is not + * retryable: the user should pick another name, or update the + * existing table + */ + long create(TableMetadata table) throws DuplicateKeyException; + + /** + * Update a table definition. + * <p> + * If {@code oldVersion == 0}, overwrites any current content. + * This is a potential race conditions if this is a partial update + * because of the possibility of another user doing an update since the + * read. Fine when the goal is to replace the entire definition. + * Else, only does the update is at the given version. + * <p> + * Retryable only if the version is given, and an + * {@code OutOfDateException} is thrown. + */ + long update(TableMetadata table, long oldVersion) throws OutOfDateException, NotFoundException; Review Comment: Should we have a separate version that does not take a version. That way this method is always updating given a current version, and the other method could always just force update whatever the current version is? I'm thinking of a scenario where a user mistakenly forces update to the table because they mistakenly provided t oldVersion of 0. Providing another method that makes the intent to force update clear I think would help to avoid that. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
