Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Dec 27, 2010 at 6:42 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> Idea is to reduce lock level of ADD/DROP COLUMN from AccessExclusiveLock
>> down to ShareRowExclusiveLock.
>>
>> To make it work, we need to recognise that we are adding a column
>> without rewriting the table.
> Can you elaborate on why you think that's the right test? It seems to
> me there could be code out there that assumes that the tuple
> descriptor won't change under it while it holds an AccessShareLock.
s/could/definitely is/
I think this is guaranteed to break stuff; to the point that I'm
not even going to review the proposal in any detail.
regards, tom lane