FANNG1 commented on code in PR #8696: URL: https://github.com/apache/gravitino/pull/8696#discussion_r2446712780
########## iceberg/iceberg-common/src/main/java/org/apache/gravitino/iceberg/common/cache/BaseTableMetadataCache.java: ########## @@ -0,0 +1,84 @@ +/* + * 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.gravitino.iceberg.common.cache; + +import java.util.Optional; +import org.apache.iceberg.TableMetadata; +import org.apache.iceberg.catalog.TableIdentifier; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Abstract base class implementing {@link TableMetadataCache} that provides core metadata caching + * functionality with validation of metadata location against the latest version. + */ +public abstract class BaseMetadataCache implements TableMetadataCache { + + public static final Logger LOG = LoggerFactory.getLogger(BaseMetadataCache.class); + /** Component to retrieve the latest metadata location for a table, used for validation. */ + private SupportsMetadataLocation supportsMetadataLocation; + + /** + * Abstract method to retrieve cached {@link TableMetadata} for a table. Subclasses must implement + * this to provide actual cache retrieval logic. + * + * @param tableIdentifier Identifier of the table to retrieve cached metadata for + * @return Cached {@link TableMetadata} wrapped in an {@link Optional}, or an empty {@link + * Optional} if not found in cache + */ + protected abstract Optional<TableMetadata> doGetTableMetadata(TableIdentifier tableIdentifier); + + protected void initialize(SupportsMetadataLocation supportsMetadataLocation) { + this.supportsMetadataLocation = supportsMetadataLocation; + } + + /** + * Retrieves and validates cached table metadata by comparing the cached metadata's location with + * the latest known location. Invalidates the cache if locations mismatch. + * + * @param tableIdentifier Identifier of the table to retrieve metadata for + * @return Valid {@link TableMetadata} if cache is valid and locations match; {@code null} if + * cache miss, location is invalid, or locations mismatch (after invalidation) + */ + @Override + public Optional<TableMetadata> getTableMetadata(TableIdentifier tableIdentifier) { + Optional<TableMetadata> tableMetadataOptional = doGetTableMetadata(tableIdentifier); + if (!tableMetadataOptional.isPresent()) { + return Optional.empty(); + } + TableMetadata tableMetadata = tableMetadataOptional.get(); + String latestLocation = supportsMetadataLocation.metadataLocation(tableIdentifier); + if (latestLocation == null) { + return Optional.empty(); + } + if (latestLocation.equals(tableMetadata.metadataFileLocation())) { + return Optional.of(tableMetadata); + } + + LOG.debug( + "The cached table metadata is not latest, table identifier: {}, " + + "table metadata location in cache: {}, latest metadata location: {}", + tableIdentifier, + tableMetadata.metadataFileLocation(), + latestLocation); + invalidate(tableIdentifier); + return Optional.empty(); + } Review Comment: Concurrent update to the same table is not common, we could leverage the table metadata location check to grant the correctness to avoid the complicated lock or cas mechanism. -- 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]
