mahesh kumar behera created HIVE-24373:
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Summary: Wrong predicate is pushed down for view with constant
value projection.
Key: HIVE-24373
URL: https://issues.apache.org/jira/browse/HIVE-24373
Project: Hive
Issue Type: Bug
Reporter: mahesh kumar behera
Assignee: mahesh kumar behera
For below query the predicate pushed down for one of the table scan is not
proper.
{code:java}
set hive.explain.user=false;
set hive.cbo.enable=false;
set hive.optimize.ppd=true;DROP TABLE arc;
CREATE table arc(`dt_from` string, `dt_to` string);
CREATE table loc1(`dt_from` string, `dt_to` string);
CREATE
VIEW view AS
SELECT
'9999' as DT_FROM,
uuid() as DT_TO
FROM
loc1
UNION ALL
SELECT
dt_from as DT_FROM,
uuid() as DT_TO
FROM
arc;
EXPLAIN
SELECT
dt_from, dt_to
FROM
view
WHERE
'2020' between dt_from and dt_to;
{code}
For table loc1, DT_FROM is projected as '9999' so the predicate "predicate:
'2020' BETWEEN '9999' AND _col1 (type: boolean)" is proper. But for table arc,
the column is projected so the predicate should be "predicate: '2020' BETWEEN
_col0 (type: boolean) AND _col1 (type: boolean)".
This is because the predicates are stored in a map for each expression. Here
the expression is "_col0". When the predicate is pushed down the union, the
same predicate is used for creating the filter expression. Later when constant
replacement is done, the first filter is overwriting the second one.
So we should create a clone (as done at other places) before using the cached
predicate for filter. This way the overwrite can be avoided.
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