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https://issues.apache.org/jira/browse/FLINK-33863?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yanfei Lei reassigned FLINK-33863:
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Assignee: Ruibin Xing
> Compressed Operator state restore failed
> ----------------------------------------
>
> Key: FLINK-33863
> URL: https://issues.apache.org/jira/browse/FLINK-33863
> Project: Flink
> Issue Type: Bug
> Components: Runtime / State Backends
> Affects Versions: 1.18.0
> Reporter: Ruibin Xing
> Assignee: Ruibin Xing
> Priority: Major
> Labels: pull-request-available
>
> We encountered an issue when using Flink 1.18.0. Our job enabled Snapshot
> Compression and used multiple operator states and broadcast states in an
> operator. When recovering Operator State from a Savepoint, the following
> error occurred: "org.xerial.snappy.SnappyFramedInputStream: encountered EOF
> while reading stream header."
> After researching, I believe the error is due to Flink 1.18.0's support for
> Snapshot Compression on Operator State (see
> https://issues.apache.org/jira/browse/FLINK-30113 ). When writing a
> Savepoint, SnappyFramedInputStream adds a header to the beginning of the
> data. When recovering Operator State from a Savepoint,
> SnappyFramedInputStream verifies the header from the beginning of the data.
> Currently, when recovering Operator State with Snapshot Compression enabled,
> the logic is as follows:
> For each OperatorStateHandle:
> 1. Verify if the current Savepoint stream's offset is the Snappy header.
> 2. Seek to the state's start offset.
> 3. Read the state's data and finally seek to the state's end offset.
> (See:
> [https://github.com/apache/flink/blob/ef2b626d67147797e992ec3b338bafdb4e5ab1c7/flink-runtime/src/main/java/org/apache/flink/runtime/state/OperatorStateRestoreOperation.java#L172]
> )
> Furthermore, when there are multiple Operator States, they are not sorted
> according to the Operator State's offset. The broadcast states will always be
> written to the end of the savepoint. However when reading from savepoint,
> there are no guarantee that broadcast states will be read at last.
> Therefore, if the Operator States are out of order and the final offset is
> recovered first, the Savepoint stream will be seeked to the end, resulting in
> an EOF error.
> I propose a solution: sort the OperatorStateHandle by offset and then recover
> the Operator State in order. After testing, this approach resolves the issue.
> I will submit a PR. This is my first time contributing code, so any help is
> really appreciated.
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