Attached is a sample query which takes abnormally long if run in the SQL Dev for VSCode extension.
sqldev-extension-sample-slow-qry.sql
It's not an issue in the query, nor in the database: the same query executes in the blink of an eye in SQL Developer “Classic”.
Developer tools in VSCode suggest that no significant activity takes place in the VSCode front-end while we're waiting for the results. On the other hand, the Java back-end seems a little busier; CPU sampling in VisualVM hints that a lot of Arbori activity may be happening behind the scenes—possibly causing excessive overhead?
Regards,