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Posted to dev@tez.apache.org by "Rajesh Balamohan (Jira)" <ji...@apache.org> on 2020/07/30 04:59:00 UTC

[jira] [Created] (TEZ-4209) Use task counter information to compute keycount during hashtable loading

Rajesh Balamohan created TEZ-4209:
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             Summary: Use task counter information to compute keycount during hashtable loading
                 Key: TEZ-4209
                 URL: https://issues.apache.org/jira/browse/TEZ-4209
             Project: Apache Tez
          Issue Type: Bug
            Reporter: Rajesh Balamohan


There are cases when compiler misestimates key count and this results in a number of hashtable resizes during runtime.

[https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/mapjoin/fast/VectorMapJoinFastHashTableLoader.java#L128]

In such cases, it would be good to get "approximate_input_records" (TEZ-4207) counter from upstream to compute the key count more accurately at runtime.

 



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