[IMPALA-4112] RQG-on-HIve: Remove IS [NOT] DISTINCT FROM clauses from Hive generated queries

• Type: Task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.2.4
• Fix Version/s: Impala 2.8.0
• Component/s: Infrastructure
• Target Version: Product Backlog
• Assignee: Sahil Takiar
• Reporter: Sahil Takiar
• Created: 09/Sep/16 21:43
• Updated: 12/Sep/16 18:14
• Resolved: 12/Sep/16 17:47

Description

The clause is used as a null-safe equality operator and is supported in both Impala and Postgres. In Hive it is implemented as "<=>" (which is what MySQL does).

https://wiki.postgresql.org/wiki/Is_distinct_from
http://dev.mysql.com/doc/refman/5.7/en/comparison-operators.html#operator_equal-to
https://issues.cloudera.org/browse/IMPALA-2147
https://issues.apache.org/jira/browse/HIVE-2810

The RQG should be modified to use <=> instead of IS NOT DISTINCT FROM for Hive queries