Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> I do remember that discussion. Aside from the problem you mention, it
> also seems that maintaining the hash table and doing lookups into it
> would have some intrinsic cost.
Well, sure, but it's still far cheaper than going out to the toast table
(which will require multiple hashtable lookups, not to mention I/O and
possible lock blocking). If we could solve the refcounting problem I
think this would be a very significant win.
regards, tom lane