All accesses to the BACKUP directory need to be protected by the same lock. The lock already existed (GDKtmLock), but wasn't used consistently. This is now fixed. Hopefully this makes the hot snapshot code more reliable.
When exiting, long running instructions are aborted using the same mechanism that is used for query timeouts.
GLOBAL TEMPORARY tables are now treated like LOCAL TEMPORARY tables as far as the table content is concerned. The schema information stays global. This fixes an issue with concurrent access and cleanup of stale data.
The NO CONSTRAINT option of the COPY INTO query has been removed. It didn't work and it was never a good idea anyway.