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amansinha100 authored and Impala Public Jenkins committed 08a7569 Jul 2, 2020
IMPALA-9911: Fix IS [NOT] NULL predicate selectivity
When null count is 0, the IsNullPredicate's selectivity
was not being computed since it did not distinguish
between a -1 (no stats) vs a 0 null count. This caused
a default selectivity estimate being applied. This
patch fixes it by explicitly checking whether nulls
count stat is present and if so, use it regardless of
whether it is 0 or more.

 - Added cardinality tests for IS NULL and IS NOT NULL.
 - Ran PlannerTest and updated baseline plans.
 - Updated expected selectivity for null predicate tests
   in ExprCardinalityTest.
 - Ran precommit tests through gerrit-verify-dryrun

Change-Id: I46c084be780b8f5aead9e2b9656fbab6cc8c8874
Reviewed-by: Impala Public Jenkins <>
Tested-by: Impala Public Jenkins <>


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Welcome to Impala

Lightning-fast, distributed SQL queries for petabytes of data stored in Apache Hadoop clusters.

Impala is a modern, massively-distributed, massively-parallel, C++ query engine that lets you analyze, transform and combine data from a variety of data sources:

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