[FLINK-29677] Prevent dropping the current catalog

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.16.0, 1.17.0
• Fix Version/s: 1.17.0, 1.16.1
• Component/s: Table SQL / API
• Labels: pull-request-available
• Assignee: Jane Chan
• Reporter: Jane Chan
• Created: 18/Oct/22 09:06
• Updated: 24/Nov/22 19:28
• Resolved: 24/Oct/22 07:00

Description

Issue Description

Currently, the drop catalog statement

 

DROP CATALOG my_cat

 

does not reset the current catalog. As a result, if dropping a catalog in use, then the following statements will yield different results.

 

SHOW CURRENT CATALOG
SHOW CATALOGS

 

How to Reproduce

 

Proposed Fix Plan

The root cause is that `CatalogManager#unregisterCatalog` does not reset `currentCatalogName`. 

Regarding this issue, I checked MySQL and PG's behavior.

For MySQL, it is allowed to drop a database current-in-use and set the current database to NULL.

 

For PG, it is not allowed to drop the database currently in use.

 

I think both behaviors are reasonable, while for simplicity I suggest adhering to PG, that throw an Exception when dropping the current catalog.

cc jark  fsk119  

Issue Links

• is related to: FLINK-17357 add "DROP catalog" DDL to blink planner
• links to: GitHub Pull Request #6248
• links to: GitHub Pull Request #21097
• links to: GitHub Pull Request #21134