Re: [HACKERS] Mapping MERGE onto CTEs (Re: MERGE SQL Statement forPG11)

Nico Williams wrote:

> As an aside, I'd like to be able to control which CTEs are view-like and
> which are table-like.  In SQLite3, for example, they are all view-like,
> and the optimizer will act accordingly, whereas in PG they are all
> table-like, and thus optimizer barriers.

There was a short and easy to grasp (OK, maybe not) discussion on the
topic of CTEs acting differently.  I think the consensus is that for
CTEs that are read-only and do not use functions that aren't immutable,
they may be considered for inlining.
https://www.postgresql.org/message-id/5351711493487900@web53g.yandex.ru

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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