On 12/04/2010 11:56 AM, Tom Lane wrote:
> Greg Stark<gsstark@mit.edu> writes:
>
>> [ suggestion for cross-table indexes ]
> That's been proposed before, and shot down before, though I don't recall
> all the reasons offhand. One obvious problem is VACUUM, which assumes
> that you can't have two processes trying to vacuum the same index
> concurrently. Another is what happens when you drop one of the tables
> involved in the index. Even the locking involved to make a uniqueness
> check against a different table would be not-nice (locking a table after
> you already have lock on its index risks deadlock against operations
> going the other way).
>
>
Those are difficulties, certainly. Are they insurmountable obstacles,
though? This is something that has been on the TODO list for ages and I
think is very worth doing, if we can.
cheers
andrew
