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Posted to issues@flink.apache.org by "Yun Tang (Jira)" <ji...@apache.org> on 2021/08/25 03:05:00 UTC
[jira] [Assigned] (FLINK-23949) first incremental checkpoint after
a savepoint will degenerate into a full checkpoint
[ https://issues.apache.org/jira/browse/FLINK-23949?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Yun Tang reassigned FLINK-23949:
--------------------------------
Assignee: Feifan Wang
> first incremental checkpoint after a savepoint will degenerate into a full checkpoint
> -------------------------------------------------------------------------------------
>
> Key: FLINK-23949
> URL: https://issues.apache.org/jira/browse/FLINK-23949
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / State Backends
> Affects Versions: 1.11.4, 1.12.5, 1.13.2
> Reporter: Feifan Wang
> Assignee: Feifan Wang
> Priority: Major
> Labels: pull-request-available
> Attachments: image-2021-08-25-00-59-05-779.png
>
>
> In RocksIncrementalSnapshotStrategy we will record the uploaded rocksdb files corresponding to the checkpoint id，and clean it in _CheckpointListener#notifyCheckpointComplete ._
> {code:java}
> @Override
> public void notifyCheckpointComplete(long completedCheckpointId) {
> synchronized (materializedSstFiles) {
> if (completedCheckpointId > lastCompletedCheckpointId) {
> materializedSstFiles
> .keySet()
> .removeIf(checkpointId -> checkpointId < completedCheckpointId);
> lastCompletedCheckpointId = completedCheckpointId;
> }
> }
> }{code}
>
> This works well without savepoint, but when a savepoint is completed, it will clean up the _materializedSstFiles_ of the previous checkpoint. It leads to the first checkpoint after the savepoint must upload all files in rocksdb.
> !image-2021-08-25-00-59-05-779.png|width=1188,height=163!
> Solving the problem is also very simple, I propose to clean _materializedSstFiles_ and update _lastCompletedCheckpointId_ only when {color:#ff0000}_materializedSstFiles.keySet().contains(completedCheckpointId)_{color} .
> If a _completedCheckpointId_ is not in _materializedSstFiles.keySet()_ , there are only two cases：
> 1. It is a checkpoint but there is a checkpoint with larger id number completed before it
> 2. It is a savepoint (savepoint not produce by RocksIncrementalSnapshotStrategy)
> In either case we don’t need clean _materializedSstFiles_ and update _lastCompletedCheckpointId_ anymore.
> [~yunta] , [~trohrmann] , I have submitted a pull request to solve this problem, please evaluate whether it is appropriate.
>
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