flyrain commented on code in PR #4870: URL: https://github.com/apache/iceberg/pull/4870#discussion_r909111695
########## api/src/main/java/org/apache/iceberg/ChangelogScanTask.java: ########## @@ -0,0 +1,40 @@ +/* + * 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; + +/** + * A changelog scan task. + */ +public interface ChangelogScanTask extends FileScanTask { + /** + * Returns the operation type (i.e. insert/delete). + */ + ChangelogOperation operation(); + + /** + * Returns the relative commit order in which the changes must be applied. + */ + int commitOrder(); + + /** + * Returns the snapshot ID in which the changes were committed. + */ + long commitSnapshotId(); Review Comment: > I think the point is that we can read data files normally and apply deletes to easily produce the squashed version, which could be quite valuable to end users. Yes. That's one of the use case we think of, which could be resolved by separating the tasks. Here is another one, which is a bit different from the above use case, `S1` adds rows with ids 4, 5, and 6, then `S2` deletes the rows with id 5 and 7, `S2` also adds the rows with id 8, 9. We want to have a single `AddedRowsScanTask` to get all added rows with s1 and s2. To give one snapshot id doesn't make sense since added rows 4, 6, 8, 9 come from different snapshots. Of course, we archive the same result by splitting it into two `AddedRowsScanTask`s, and merge them later. But a task across multiple multiple snapshots may have perf advantage, or simpler implementation for that use case. What do you think? -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
