redshift drop or truncate table very very slow

Question

When drop or truncate a not too big table(4M rows) in my redshift database, it take very very long(hours) to complete. Does anybody experience the same issue?

Thanks

Answer 1

Redshift has very fast I/O, so that opeation should take less than 1 second for any cluster type or size. As diemacht said, the issue is caused because you have another connection with an open transaction.

I had a similar issue: A crash on the client left a transaction 'open' but unreacheable. No db locks appeared on the STV_LOCKS table: (using select table_id, last_update, lock_owner, lock_owner_pid from stv_locks;)

Also, no query was still running: (checked with: select pid, trim(user_name), starttime, query , substring(query,1,20), status from stv_recents where status='Running';)

So the solution was to list the user sessions: SELECT * FROM STV_SESSIONS And then kill it using: SELECT pg_terminate_backend(pid)

Or the KILL'EM ALL version:

SELECT pg_terminate_backend(process) FROM STV_SESSIONS where user_name='user_name' and process != pg_backend_pid(); 

Note that CANCEL {pid} did not work! (the query was cancelled but the transaction was still open and locking).