[HAWQ-55] System admin cannot set optimizer_release_mdcache (OFF) when gp_metadata_versioning is (OFF)

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Not A Problem
• Fix Version/s: 2.0.0.0-incubating
• Component/s: Metadata Versioning
• Labels: closed-pr
• Assignee: George Caragea
• Reporter: George Caragea
• Created: 13/Oct/15 18:10
• Updated: 14/Jul/16 18:26
• Resolved: 14/Jul/16 18:26

Description

As a system admin, I should not be able to set optimizer_release_mdcache (OFF) when gp_metadata_versioning is (OFF) so that I cannot get into a incorrect state with unexpected behavior from the host system.

Acceptance Criteria
GIVEN I am a system
AND gp_metadata_versioning is OFF
WHEN I try to set optimizer_release_mdcache (OFF)
THEN I should see a warning message stating that if optimizer_release_mdcache is to be turned OFF, set gp_metadata_versioning should be turned ON

Context
Default:
optimizer_release_mdcache (ON)
gp_metadata_versioning (OFF)

Bad state: We don't want the user to be able to do this
optimizer_release_mdcache (OFF)
gp_metadata_versioning (OFF)

If a user turns optimizer_release_mdcache (OFF), then gp_metadata_versioning should be turned (ON). Otherwise, the optimizer can end up using stale data in the metadata cache, generating unexpected behavior.