Github user StefanRRichter commented on the issue: https://github.com/apache/flink/pull/5937 @bowenli86 I already wanted to do this for some time but unfortunately we currently cannot upgrade RocksDB to any higher version than what is used in master. It seems like there is again a performance regression for the merge operator for all newer versions. If you check your Travis runs, you will see that `RocksDBPerformanceTest.testRocksDbMergePerformance` fails all the time. I have commented about this problem in the RocksDB issue tracker, but no reaction so far. If you agree, please close this PR.
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