On Thu, Jun 11, 2015 at 1:23 PM, Peter Geoghegan <pg@heroku.com> wrote:
> I'm not sure if it's worth mentioning the "cheap equality for text"
> commit (e246b3d6eac09). I guess that it probably is, because it will
> help with things like index scans, too. Arguably that isn't a sorting
> thing (it's certainly not *just* a sorting thing).
I think we should really address this. Attached patch adds a new
release note item for it. It also adds to the documentation that
explains why users should prefer varchar(n)/text to character(n); the
lack of abbreviated key support now becomes a huge disadvantage for
character(n), whereas in previous versions the disadvantages were
fairly minor.
In passing, I updated the existing sort item to reflect that only
varchar(n), text, and numeric benefit from the abbreviation
optimization (not character types more generally + numeric), and added
a note on the effectiveness of the abbreviation optimization alone.
--
Peter Geoghegan