[jira] [Created] (IMPALA-8809) Refresh a subset of partitions for ACID tables

["Gabor Kaszab (JIRA)" <ji...@apache.org>]

Gabor Kaszab created IMPALA-8809:
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             Summary: Refresh a subset of partitions for ACID tables
                 Key: IMPALA-8809
                 URL: https://issues.apache.org/jira/browse/IMPALA-8809
             Project: IMPALA
          Issue Type: Improvement
    Affects Versions: Impala 3.3.0
            Reporter: Gabor Kaszab


Enhancing REFRESH logic to handle ACID tables was covered by this change: https://issues.apache.org/jira/browse/IMPALA-8600
Basically each user initiated REFRESH PARTITION is rejected meanwhile the REFRESH_PARTITION event in event processor are actually doing a full table load for ACID tables.

There is room for improvement: When a full table refresh is being executed on an ACID table we can have 2 scenarios:
- If there was some schema changes then reload the full table. Identify such a scenario should be possible by checking the table-level writeId. However, there is a bug in Hive that it doesn't update that field for partitioned tables (https://issues.apache.org/jira/browse/HIVE-22062). This would be the desired way but could also be workarounded by checking other fields lik lastDdlChanged or such.
- If a full table refresh is not needed then we should fetch the partition-level writeIds and reload only the ones that are out-of-date locally.



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