Jesus Camacho Rodriguez created HIVE-21857:
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Summary: Sort conditions in a filter predicate to accelerate query
processing
Key: HIVE-21857
URL: https://issues.apache.org/jira/browse/HIVE-21857
Project: Hive
Issue Type: Bug
Components: CBO
Reporter: Jesus Camacho Rodriguez
Assignee: Jesus Camacho Rodriguez
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.
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