thiagotnunes commented on code in PR #32689: URL: https://github.com/apache/beam/pull/32689#discussion_r1792726011
########## sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/changestreams/dao/PartitionMetadataTableNames.java: ########## @@ -0,0 +1,147 @@ +/* + * 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.beam.sdk.io.gcp.spanner.changestreams.dao; + +import java.io.Serializable; +import java.util.Objects; +import java.util.UUID; +import javax.annotation.Nullable; +import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.annotations.VisibleForTesting; + +/** + * Configuration for a partition metadata table. It encapsulates the name of the metadata table and + * indexes. + */ +public class PartitionMetadataTableNames implements Serializable { + + private static final long serialVersionUID = 8848098877671834584L; + + /** PostgreSQL max table and index length is 63 bytes. */ + @VisibleForTesting static final int MAX_NAME_LENGTH = 63; + + private static final String PARTITION_METADATA_TABLE_NAME_FORMAT = "Metadata_%s_%s"; + private static final String WATERMARK_INDEX_NAME_FORMAT = "WatermarkIdx_%s_%s"; + private static final String CREATED_AT_START_TIMESTAMP_INDEX_NAME_FORMAT = "CreatedAtIdx_%s_%s"; + + /** + * Generates a unique name for the partition metadata table and its indexes. The table name will + * be in the form of {@code "Metadata_<databaseId>_<uuid>"}. The watermark index will be in the + * form of {@code "WatermarkIdx_<databaseId>_<uuid>}. The createdAt / start timestamp index will + * be in the form of {@code "CreatedAtIdx_<databaseId>_<uuid>}. + * + * @param databaseId The database id where the table will be created + * @return the unique generated names of the partition metadata ddl + */ + public static PartitionMetadataTableNames from(String databaseId) { + UUID uuid = UUID.randomUUID(); + String table = + String.format(PARTITION_METADATA_TABLE_NAME_FORMAT, databaseId, uuid) + .replaceAll("-", "_") + .substring(0, MAX_NAME_LENGTH); + String watermarkIndex = + String.format(WATERMARK_INDEX_NAME_FORMAT, databaseId, uuid) + .replaceAll("-", "_") + .substring(0, MAX_NAME_LENGTH); + String createdAtIndex = + String.format(CREATED_AT_START_TIMESTAMP_INDEX_NAME_FORMAT, databaseId, uuid) + .replaceAll("-", "_") + .substring(0, MAX_NAME_LENGTH); + + return new PartitionMetadataTableNames(table, watermarkIndex, createdAtIndex); + } + + /** + * Generates a unique name for the partition metadata indexes. Uses the given table name. The + * watermark index will be in the form of {@code "WatermarkIdx_<databaseId>_<uuid>}. The createdAt + * / start timestamp index will be in the form of {@code "CreatedAtIdx_<databaseId>_<uuid>}. + * + * @param databaseId The database id where the table will be created + * @param table The table name to be used + * @return the unique generated names of the partition metadata ddl + */ + public static PartitionMetadataTableNames from(String databaseId, String table) { + UUID uuid = UUID.randomUUID(); Review Comment: Hum, so the index names are generated in any case, but the index is only created if the table does not already exist. See https://github.com/apache/beam/blob/master/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/changestreams/dofn/InitializeDoFn.java#L66-L67). I acknowledge this is confusing, so maybe we want to explore a different solution here. In any case, the code as is would cause an issue on drop, since the index names we would try to drop would not exist. I added a `DROP INDEX IF EXISTS ...` This solves one problem, but the other problem is that if we don't know the name of the indices in a table, we wouldn't be able to drop the metadata table on cleanup, since in Spanner you cannot drop a table that has indexes. I think we need to do some introspection in the information schema to do this properly. Let me work on this. -- 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]
