api/src/main/java/org/apache/iceberg/ExpireSnapshots.java

/*
 * 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.iceberg;

import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.function.Consumer;

/**
 * API for removing old {@link Snapshot snapshots} from a table.
 * <p>
 * This API accumulates snapshot deletions and commits the new list to the table. This API does not
 * allow deleting the current snapshot.
 * <p>
 * When committing, these changes will be applied to the latest table metadata. Commit conflicts
 * will be resolved by applying the changes to the new latest metadata and reattempting the commit.
 * <p>
 * Manifest files that are no longer used by valid snapshots will be deleted. Data files that were
 * deleted by snapshots that are expired will be deleted. {@link #deleteWith(Consumer)} can be used
 * to pass an alternative deletion method.
 *
 * {@link #apply()} returns a list of the snapshots that will be removed.
 */
public interface ExpireSnapshots extends PendingUpdate<List<Snapshot>> {

  /**
   * Expires a specific {@link Snapshot} identified by id.
   *
   * @param snapshotId long id of the snapshot to expire
   * @return this for method chaining
   */
  ExpireSnapshots expireSnapshotId(long snapshotId);

  /**
   * Expires all snapshots older than the given timestamp.
   *
   * @param timestampMillis a long timestamp, as returned by {@link System#currentTimeMillis()}
   * @return this for method chaining
   */
  ExpireSnapshots expireOlderThan(long timestampMillis);

  /**
   * Retains the most recent ancestors of the current snapshot.
   * <p>
   * If a snapshot would be expired because it is older than the expiration timestamp, but is one of
   * the {@code numSnapshots} most recent ancestors of the current state, it will be retained. This
   * will not cause snapshots explicitly identified by id from expiring.
   * <p>
   * This may keep more than {@code numSnapshots} ancestors if snapshots are added concurrently. This
   * may keep less than {@code numSnapshots} ancestors if the current table state does not have that many.
   *
   * @param numSnapshots the number of snapshots to retain
   * @return this for method chaining
   */
  ExpireSnapshots retainLast(int numSnapshots);

  /**
   * Passes an alternative delete implementation that will be used for manifests and data files.
   * <p>
   * Manifest files that are no longer used by valid snapshots will be deleted. Data files that were
   * deleted by snapshots that are expired will be deleted.
   * <p>
   * If this method is not called, unnecessary manifests and data files will still be deleted.
   *
   * @param deleteFunc a function that will be called to delete manifests and data files
   * @return this for method chaining
   */
  ExpireSnapshots deleteWith(Consumer<String> deleteFunc);

  /**
   * Passes an alternative executor service that will be used for manifests and data files deletion.
   * <p>
   * Manifest files that are no longer used by valid snapshots will be deleted. Data files that were
   * deleted by snapshots that are expired will be deleted.
   * <p>
   * If this method is not called, unnecessary manifests and data files will still be deleted using a single threaded
   * executor service.
   *
   * @param executorService an executor service to parallelize tasks to delete manifests and data files
   * @return this for method chaining
   */
  ExpireSnapshots executeDeleteWith(ExecutorService executorService);

  /**
   * Allows expiration of snapshots without any cleanup of underlying manifest or data files.
   * <p>
   * Allows control in removing data and manifest files which may be more efficiently removed using
   * a distributed framework through the actions API.
   *
   * @param clean setting this to false will skip deleting expired manifests and files
   * @return this for method chaining
   */
  ExpireSnapshots cleanExpiredFiles(boolean clean);
}