Peter Geoghegan <pg@heroku.com> writes:
> On Thu, Jan 30, 2014 at 4:34 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Quite aside from the index bloat risk, this effect means a 3-4x reduction
>> in the maximum string length that can be indexed before getting the
>> dreaded "Values larger than 1/3 of a buffer page cannot be indexed" error.
>> Worse, a value insertion might well succeed, with the failure happening
>> only (much?) later when that entry is chosen as a page split boundary.
> That's not hard to prevent. If that should happen, we don't go with
> the strxfrm() datum. We have a spare IndexTuple bit we could use to
> mark when the optimization was applied.
You'd need a bit per column, no?
regards, tom lane