Re: [HACKERS] CTE inlining

On Tue, May  9, 2017 at 05:14:19PM -0400, Tom Lane wrote:
> Ilya Shkuratov  writes:
> > Ok, it seems that most people in discussion are agree that removing optimization
> > fence is a right thing to do.
> > Nonetheless I still hoping to discuss the algorithm and its implementation. 
> 
> Yeah, so far we've mainly discussed whether to do that and how to control
> it, not what the actual results would be.

To summarize, it seems we have two options if we want to add fence
control to CTEs:

1.  add INLINE to disable the CTE fence
2.  add MATERIALIZE to enable the CTE fence

or some other keywords.  I think most people prefer #2 because:

*  most users writing queries prefer #2
*  most users assume full optimization and it seems natural to turn  _off_ an optimization via a keyword 
*  while some queries can be inlined, all queries can be materialized,  so doing #1 means INLINE would be only a preference, which could be  confusing

Anyway, I am very glad we are considering addressing this in PG 11.

--  Bruce Momjian          http://momjian.us EnterpriseDB                             http://enterprisedb.com

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