On 2020-02-27 10:52:36 -0500, Tom Lane wrote: > FWIW, I can't immediately think of a reason this would cause a problem, > at least not on 9.4 and up which use MVCC catalog scans. If you're > really still on 9.3 then it's notably more risky. In any case, I've > not had any caffeine yet today, so this doesn't count for much.
It likely could cause some problems if somebody concurrently executed DDL affecting the same table. At least some "concurrently updated" errors, and perhaps some worse ones. I'd at least add an explicit LOCK TABLE on the underlying table that prevents concurrent catalog modifications.
I am trying to escape the Access Exclusive lock over the table indeed, otherwise I would use the ALTER statement instead anyway, which makes a lock implicitly. Thanks for the responses. There is nobody else doing DDLs except me - Mr. DBA, so I guess I am safe on this side. ;)