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When I try to use impala to transfer massive data (about 100G) for one time and select count(1) immediately, I get the wrong total count. Then I execute the same sql again, the total count is correct.

I want to know besides leader change, is there have any other internal ops can cause the scan inconsistency? If I change the impala configure kudu_read_mode: READ_LATEST to kudu_read_mode: READ_AT_SNAPSHOT, what's the timestamp that the impala will transimit? If the READ_AT_SNAPSHOT can resolve the issue?

I am using the impala 2.10.0 + kudu 1.5.0.

tk421
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Tony Li
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  • Most databases only offer up to serializable consistency, which is likely the case here. A read that returns a previous count would be serializable, even if the write that changes the count has completed. – GManNickG Dec 16 '17 at 17:55
  • here is the answer from cloudra: https://community.cloudera.com/t5/Interactive-Short-cycle-SQL/KUDU-Does-impala-scan-READ-LATEST-mode-inconsistency-only-arise/m-p/62406#M3890 – Tony Li Dec 26 '17 at 08:42

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