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Posted to issues@trafodion.apache.org by "Hans Zeller (JIRA)" <ji...@apache.org> on 2017/10/10 15:12:00 UTC
[jira] [Updated] (TRAFODION-1987) Enable min/max optimization for
TYPE 2 repartitioned joins
[ https://issues.apache.org/jira/browse/TRAFODION-1987?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Hans Zeller updated TRAFODION-1987:
-----------------------------------
Fix Version/s: (was: 2.2-incubating)
> Enable min/max optimization for TYPE 2 repartitioned joins
> ----------------------------------------------------------
>
> Key: TRAFODION-1987
> URL: https://issues.apache.org/jira/browse/TRAFODION-1987
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-cmp
> Affects Versions: 1.3-incubating
> Reporter: Hans Zeller
> Assignee: Hans Zeller
>
> Right now, min/max optimization for hash joins (making min and max values of equi-join columns available to the outer child tree of a hash join) is limited to operators in the same plan fragment. In other words, an ESP_EXCHANGE between a scan and a hash join makes it impossible to do this optimization. We could be a bit less restrictive: If the hash table of the hash join isn't partitioned, either because it runs in a single instance, or because its right (inner) child is replicated, then we can do this optimization across exchanges.
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