Vineet Garg created HIVE-18490:
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Summary: Query with EXISTS and NOT EXISTS with non-equi predicate
can produce wrong result
Key: HIVE-18490
URL: https://issues.apache.org/jira/browse/HIVE-18490
Project: Hive
Issue Type: Bug
Reporter: Vineet Garg
Assignee: Vineet Garg
Attachments: HIVE-18490.1.patch
Queries such as following can produce wrong result
{code:sql}
select
count(ws_order_number)
from
web_sales ws1
where
and exists (select *
from web_sales ws2
where ws1.ws_order_number = ws2.ws_order_number
and ws1.ws_warehouse_sk <> ws2.ws_warehouse_sk)
and not exists(select *
from web_returns wr1
where ws1.ws_order_number = wr1.wr_order_number);
{code}
This query is simplified version of tpcds query 94. Such queries are rewritten
into LEFT SEMI JOIN and LEFT OUTER JOIN with residual predicate/filter
(non-equi join key). Problem is that these joins are being merged, we shouldn't
be merging since semi join has non-equi join filter.
Basically the underlying issue is that if a query has multiple join with LEFT
SEMI JOIN with non-equi join key it is being merged with other joins. Merge
logic should check such cases and avoid merging.
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