On Wed, Oct 5, 2016 at 9:04 AM, Amit Kapila <amit.kapil...@gmail.com> wrote:
> Okay, but in that case I think we don't need to store including
> columns in non-leaf pages to get the exact ordering.  As mentioned
> upthread, we can use truncated scan key to reach to leaf level and
> then use the complete key to find the exact location to store the key.
> This is only possible if there exists an opclass for columns that are
> covered as part of including clause.  So, we can allow "order by" to
> use index scan only if the columns covered in included clause have
> opclass for btree.

But what if there are many pages full of keys that have the same
values for the non-INCLUDING columns?

Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:

Reply via email to