JingsongLi commented on a change in pull request #17: URL: https://github.com/apache/flink-table-store/pull/17#discussion_r806641782
########## File path: flink-table-store-core/src/main/java/org/apache/flink/table/store/file/operation/FileStoreExpireImpl.java ########## @@ -0,0 +1,155 @@ +/* + * 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.store.file.operation; + +import org.apache.flink.core.fs.Path; +import org.apache.flink.table.store.file.Snapshot; +import org.apache.flink.table.store.file.manifest.ManifestEntry; +import org.apache.flink.table.store.file.manifest.ManifestFileMeta; +import org.apache.flink.table.store.file.manifest.ManifestList; +import org.apache.flink.table.store.file.mergetree.sst.SstPathFactory; +import org.apache.flink.table.store.file.utils.FileStorePathFactory; +import org.apache.flink.table.store.file.utils.FileUtils; + +import java.io.IOException; +import java.util.HashSet; +import java.util.Set; + +/** + * Default implementation of {@link FileStoreExpire}. It retains a certain number or period of + * latest snapshots. + * + * <p>NOTE: This implementation will keep at least one snapshot so that users will not accidentally + * clear all snapshots. + */ +public class FileStoreExpireImpl implements FileStoreExpire { + + // snapshots exceeding any constraint will be expired + private final int numRetained; + private final long millisRetained; + + private final FileStorePathFactory pathFactory; + private final ManifestList manifestList; + private final FileStoreScan scan; + + public FileStoreExpireImpl( + int numRetained, + long millisRetained, + FileStorePathFactory pathFactory, + ManifestList.Factory manifestListFactory, + FileStoreScan scan) { + this.numRetained = numRetained; + this.millisRetained = millisRetained; + this.pathFactory = pathFactory; + this.manifestList = manifestListFactory.create(); + this.scan = scan; + } + + @Override + public void expire() { + Long latestSnapshotId = pathFactory.latestSnapshotId(); + if (latestSnapshotId == null) { + // no snapshot, nothing to expire + return; + } + + // binary search for the last snapshot to expire + long currentMillis = System.currentTimeMillis(); + long head = Math.max(Snapshot.FIRST_SNAPSHOT_ID - 1, latestSnapshotId - numRetained); + long tail = latestSnapshotId; + while (head < tail) { + long mid = (head + tail + 1) / 2; + Path snapshotPath = pathFactory.toSnapshotPath(mid); + try { + if (!snapshotPath.getFileSystem().exists(snapshotPath) + || currentMillis - Snapshot.fromPath(snapshotPath).timeMillis() + > millisRetained) { + head = mid; + } else { + tail = mid - 1; + } + } catch (IOException e) { + throw new RuntimeException( + "Failed to determine if snapshot #" + mid + " still exists", e); + } + } + + // determine the exact expire range, we also keep at least 1 snapshot not to expire + long lastSnapshotIdToExpire = Math.min(head, latestSnapshotId - 1); + long firstSnapshotIdToExpire = Snapshot.FIRST_SNAPSHOT_ID; + for (long id = lastSnapshotIdToExpire; id >= Snapshot.FIRST_SNAPSHOT_ID; id--) { + Path snapshotPath = pathFactory.toSnapshotPath(id); + try { + if (!snapshotPath.getFileSystem().exists(snapshotPath)) { + // only latest snapshots are retained, as we cannot find this snapshot, we can + // assume that all snapshots preceding it have been removed + firstSnapshotIdToExpire = id + 1; + break; + } + } catch (IOException e) { + throw new RuntimeException( + "Failed to determine if snapshot #" + id + " still exists", e); + } + } + + // expire each snapshot + for (long id = firstSnapshotIdToExpire; id <= lastSnapshotIdToExpire; id++) { + expire(id); + } + } + + private void expire(long snapshotId) { + Snapshot toExpire = Snapshot.fromPath(pathFactory.toSnapshotPath(snapshotId)); + Snapshot nextSnapshot = Snapshot.fromPath(pathFactory.toSnapshotPath(snapshotId + 1)); + + // if sst file in only used in snapshot to expire but not in next snapshot we can delete it + // because each sst file will only be added and deleted once + Set<Path> sstInUse = new HashSet<>(); + FileStorePathFactory.SstPathFactoryCache sstPathFactoryCache = + new FileStorePathFactory.SstPathFactoryCache(pathFactory); + for (ManifestEntry entry : scan.withSnapshot(nextSnapshot.id()).plan().files()) { Review comment: I can see large number of repeat reads. We can add a TODO to add manifest cache in scan. -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
