Re: WIP: extensible enums

Robert Haas <robertmhaas@gmail.com> writes:
> Why would you need to lock out type comparisons?

Didn't you get the point?  The hazard is to a concurrent process that is
merely trying to load up its enum-values cache so that it can perform an
enum comparison.  I don't want such an operation to have to block,
especially not against something that's trying to acquire a more or less
exclusive lock.
        regards, tom lane