Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>
>> Yeah. I think the correct logic is roughly this: When considering if a
>> candidate item has a locking conflict with a running item, then if
>> *either* of them has a locking dependency that coincides with *any*
>> dependency of the other item, then the candidate is rejected. The
>> principle is that we don't give any item a chance to block on a lock.
>>
>
> Doesn't that eliminate any chance of running two CREATE INDEXes
> concurrently on the same table?
>
>
>
No, since neither of them will have any locking dependencies, which are
only for items that take an exclusive lock on the table(s), such as FK
constraints.
cheers
andrew
