HIVE-18624 [1] is a serious performance bug in the SQL parser. It causes parse times that are literally exponential in the number of parentheses in the expression, thus parsing of a query that has complex expressions may take minutes or not terminate. According to JIRA, the bug was fixed on 2.4.0, 3.1.0, 4.0.0 code lines in August but has not yet been released.
I work for Looker, a BI tool that generates SQL with deeply nested expressions, and therefore they hit this bug. Hive 2.2, 2.3 and 3.0 are unusable for our customers due to this bug. I do not know the schedule for 2.4.0, 3.1.0 or 4.0.0 releases, but if they are a way off, would it be possible to fix this bug in a patch release? Julian [1] https://issues.apache.org/jira/browse/HIVE-18624 <https://issues.apache.org/jira/browse/HIVE-18624>
