Re: Making strxfrm() blobs in indexes work

Peter Geoghegan <pg(at)heroku(dot)com> writes:
> On Thu, Jan 30, 2014 at 4:34 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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