bowenli86 commented on a change in pull request #8214: [FLINK-11476] [table] Create CatalogManager to manage multiple catalogs and encapsulate Calcite schema URL: https://github.com/apache/flink/pull/8214#discussion_r280525021
########## File path: flink-table/flink-table-planner-blink/src/main/java/org/apache/flink/table/catalog/FlinkCatalogManager.java ########## @@ -0,0 +1,124 @@ +/* + * 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.flink.table.catalog; + +import org.apache.flink.table.api.CatalogAlreadyExistsException; +import org.apache.flink.table.api.CatalogNotExistException; +import org.apache.flink.util.StringUtils; + +import org.apache.calcite.jdbc.CalciteSchema; +import org.apache.calcite.schema.SchemaPlus; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.HashMap; +import java.util.Map; +import java.util.Set; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * A CatalogManager implementation for Flink. + * TODO: [FLINK-11275] Decouple CatalogManager with Calcite + * Idealy FlinkCatalogManager should be in flink-table-api-java module. + * But due to that it currently depends on Calcite, a dependency that flink-table-api-java doesn't have right now. + * We temporarily put FlinkCatalogManager in flink-table-planner-blink. + */ +public class FlinkCatalogManager implements CatalogManager { + private static final Logger LOG = LoggerFactory.getLogger(FlinkCatalogManager.class); + + public static final String BUILTIN_CATALOG_NAME = "builtin"; + + // The catalog to hold all registered and translated tables + // We disable caching here to prevent side effects + private CalciteSchema internalSchema = CalciteSchema.createRootSchema(false, false); + private SchemaPlus rootSchema = internalSchema.plus(); + + // A map between names and catalogs. + private Map<String, ReadableCatalog> catalogs; + + // The name of the default catalog and schema + private String currentCatalogName; + + public FlinkCatalogManager() { + LOG.info("Initializing FlinkCatalogManager"); + catalogs = new HashMap<>(); + + GenericInMemoryCatalog inMemoryCatalog = new GenericInMemoryCatalog(BUILTIN_CATALOG_NAME); Review comment: Good question, this PR only partially reflects the integration of `CatalogManager` and `TableEnv`. We propose adding new APIs to `TableEnv` to read/write catalog metadata. If users try to write to a `ReadableCatalog`, a catalog exception will be thrown to remind them that. E.g. for CatalogBaseTable, we'll have ``` // can have overloaded methods or a different signature to register table in a catalog different than the current one void registerTable(String name, CatalogBaseTable table, boolean ignoreIfExists) { if (!(catalogManager.getCurrentCatalog() instanceof ReadableWritableCatalog)) { throw CatalogException("xxx is a ReadableCatalog only") } catalog = (ReadableWritableCatalog) catalogManager.getCurrentCatalog() catalog.createTable(new ObjectPath(catalog.getCurrentDb(), name), table, ignoreIfExists) } ``` `ReadableCatalog` and `ReadableWritableCatalog` is inherited from the original `ExternalCatalog` and `CrudExternalCatalog`, more context in [FLIP-30](https://cwiki.apache.org/confluence/display/FLINK/FLIP-30%3A+Unified+Catalog+APIs). I believe it's good to have `ReadableCatalog`. It doesn't make sense or just cannot support writing in some catalog impl. E.g. at least for now I don't see Confluent Registry catalog ( [FLINK-12256](https://issues.apache.org/jira/browse/FLINK-12256)) needs to support writing since writing thru Confluent Registry itself and its fancy UI is much more convenient and user friendly. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
