tree 6063127457b26490475b5d4cbb0a771528065fe1
parent 749974f5323e380e0db8e62227b67fc119ac7726
author Ali Alsuliman <ali.al.solaiman@gmail.com> 1582064667 -0800
committer Ali Alsuliman <ali.al.solaiman@gmail.com> 1582138989 +0000

[ASTERIXDB-2700][*DB][RT] Fix invalid plan caused by order-by operator in a subquery

- user model changes: no
- storage format changes: no
- interface changes: no

Details:
Instead of removing a redundant sort operator from the plan, replace it with
an empty assign operator to avoid potential connection of a sort-merge connector
to another connector.

- modified RemoveUnusedAssignAndAggregateRule to excluded necessary empty
  assign operators from being removed.

Change-Id: I8bc11fa046cb15fab04057086817bd400b7809c0
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/5103
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Ali Alsuliman <ali.al.solaiman@gmail.com>
Reviewed-by: Dmitry Lychagin <dmitry.lychagin@couchbase.com>