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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-21867) Sort semijoin conditions to accelerate query processing
Date Wed, 12 Jun 2019 23:39:00 GMT

     [ https://issues.apache.org/jira/browse/HIVE-21867?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jesus Camacho Rodriguez updated HIVE-21867:
-------------------------------------------
    Description: The problem was tackled for CBO in HIVE-21857. Semijoin filters are introduced
later in the planning phase. Follow similar approach to sort them, trying to accelerate filter
evaluation.  (was: Following approach similar to http://db.cs.berkeley.edu/jmh/miscpapers/sigmod93.pdf
.

To reorder predicates in AND conditions, we could rank each of elements in the clauses in
increasing order based on following formula:
{code}
rank = (selectivity - 1) / cost per tuple
{code}
Similarly, for OR conditions:
{code}
rank = (-selectivity) / cost per tuple
{code}
Selectivity can be computed with FilterSelectivityEstimator. For cost per tuple, we will need
to come up with some heuristic based on how expensive is the evaluation of the functions contained
in that predicate. Custom UDFs could be annotated.)

> Sort semijoin conditions to accelerate query processing
> -------------------------------------------------------
>
>                 Key: HIVE-21867
>                 URL: https://issues.apache.org/jira/browse/HIVE-21867
>             Project: Hive
>          Issue Type: Bug
>          Components: CBO
>            Reporter: Jesus Camacho Rodriguez
>            Assignee: Jesus Camacho Rodriguez
>            Priority: Major
>              Labels: pull-request-available
>
> The problem was tackled for CBO in HIVE-21857. Semijoin filters are introduced later
in the planning phase. Follow similar approach to sort them, trying to accelerate filter evaluation.



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