[jira] [Created] (FLINK-26757) change the default value of state.backend.rocksdb.restore-overlap-fraction-threshold

["Yanfei Lei (Jira)" <ji...@apache.org>]

Yanfei Lei created FLINK-26757:
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             Summary: change the default value of state.backend.rocksdb.restore-overlap-fraction-threshold
                 Key: FLINK-26757
                 URL: https://issues.apache.org/jira/browse/FLINK-26757
             Project: Flink
          Issue Type: Improvement
          Components: Runtime / State Backends
            Reporter: Yanfei Lei
         Attachments: 截屏2022-03-21 上午11.50.28.png

`state.backend.rocksdb.restore-overlap-fraction-threshold` is used to control how to restore a state handle, different thresholds can affect the performance of restoring. The behavior of deletion in restoring has been changed after FLINK-21321.

In theory, setting the default value to 0 is most suitable, since `deleteRange()` takes less time than creating a new RocksDB instance and then scan-and-put the records. In fact, we also have some experimental data that the default value of 0 is more suitable. Here is a comparison of initialization times for different thresholds, we can see that the default value to 0 takes less time.

!截屏2022-03-21 上午11.50.28.png!

 



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