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https://issues.apache.org/jira/browse/HIVE-15209?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15667790#comment-15667790
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Jesus Camacho Rodriguez edited comment on HIVE-15209 at 11/15/16 5:58 PM:
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[~xuefuz], obviously it does, because if this is set to true, queries with
cartesian product throw an error.
{code:sql}
SELECT * FROM
mytable src1, mytable src2;
{code}
{quote}
org.apache.hadoop.hive.ql.parse.SemanticException: Cartesian products are
disabled for safety reasons. If you know what you are doing, please make sure
that hive.strict.checks.cartesian.product is set to false and that
hive.mapred.mode is not set to 'strict' to enable them.
{quote}
I do not not know if this property was actually ever changed, but IMO it makes
sense to set it by default to _false_ and if a user wants to have more control
over his query workload, then he can enable it.
was (Author: jcamachorodriguez):
[~xuefuz], obviously it does, because if this is set to true, queries with
cartesian product throw an error.
{code:sql}
SELECT * FROM
mytable src1 JOIN mytable src2;
{code}
{quote}
org.apache.hadoop.hive.ql.parse.SemanticException: Cartesian products are
disabled for safety reasons. If you know what you are doing, please make sure
that hive.strict.checks.cartesian.product is set to false and that
hive.mapred.mode is not set to 'strict' to enable them.
{quote}
I do not not know if this property was actually ever changed, but IMO it makes
sense to set it by default to _false_ and if a user wants to have more control
over his query workload, then he can enable it.
> Set hive.strict.checks.cartesian.product to false by default
> ------------------------------------------------------------
>
> Key: HIVE-15209
> URL: https://issues.apache.org/jira/browse/HIVE-15209
> Project: Hive
> Issue Type: Bug
> Components: Parser
> Affects Versions: 2.2.0
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-15209.patch
>
>
> If we aim to make Hive compliant with SQL, w should disable this property by
> default, as expressing a cartesian product, though inefficient, is perfectly
> valid in SQL.
> Further, if we express complex predicates in the ON clause of a SQL query, we
> might not be able to push these predicates to the join operator; however, we
> should still be able to execute the query.
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