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https://issues.apache.org/jira/browse/HIVE-14053?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pengcheng Xiong reassigned HIVE-14053:
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Assignee: Pengcheng Xiong (was: Hari Sankar Sivarama Subramaniyan)
> Hive should report that primary keys can't be null.
> ---------------------------------------------------
>
> Key: HIVE-14053
> URL: https://issues.apache.org/jira/browse/HIVE-14053
> Project: Hive
> Issue Type: Bug
> Reporter: Carter Shanklin
> Assignee: Pengcheng Xiong
> Priority: Minor
>
> HIVE-13076 introduces "rely novalidate" primary and foreign keys to Hive.
> With the right driver in place, tools like Tableau can do join elimination
> and queries can run much faster.
> Some gaps remain, currently getAttributes() in HiveDatabaseMetaData doesn't
> work quite right for keys. In particular, primary keys by definition are not
> null and the metadata should reflect this for improved join elimination.
> In this example that uses the TPC-H schema and its constraints, we sum
> l_extendedprice and group by l_shipmode. This query should not use more than
> just the lineitem table.
> With all the constraints in place, Tableau generates this query:
> {code}
> SELECT `lineitem`.`l_shipmode` AS `l_shipmode`,
> SUM(`lineitem`.`l_extendedprice`) AS `sum_l_extendedprice_ok`
> FROM `tpch_bin_flat_orc_2`.`lineitem` `lineitem`
> JOIN `tpch_bin_flat_orc_2`.`orders` `orders` ON (`lineitem`.`l_orderkey` =
> `orders`.`o_orderkey`)
> JOIN `tpch_bin_flat_orc_2`.`customer` `customer` ON (`orders`.`o_custkey` =
> `customer`.`c_custkey`)
> JOIN `tpch_bin_flat_orc_2`.`nation` `nation` ON (`customer`.`c_nationkey` =
> `nation`.`n_nationkey`)
> WHERE ((((NOT (`lineitem`.`l_partkey` IS NULL)) AND (NOT
> (`lineitem`.`l_suppkey` IS NULL))) AND ((NOT (`lineitem`.`l_partkey` IS
> NULL)) AND (NOT (`lineitem`.`l_suppkey` IS NULL)))) AND (NOT
> (`nation`.`n_regionkey` IS NULL)))
> {code}
> Since these are the primary keys the denormalization and the where condition
> is unnecessary and this sort of query can be a lot faster by just accessing
> the lineitem table.
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