Re: CTE inlining

On 05/01/2017 10:17 AM, David Fetter wrote:
> On Mon, May 01, 2017 at 09:22:42AM -0400, Andrew Dunstan wrote:
>>> So no more planner-affecting GUCs, please, particularly if we expect
>>> regular users to use them.
>> +1
>>
>> I still see users wanting to use the enable_foo settings in production.
>>
>> Having had years of telling users that CTEs are an optimization fence it
>> doesn't seem at all nice for us to turn around and change our mind about
>> that. I have relied on it in the past and I'm sure I'm very far from
>> alone in that.
> You are certainly not alone, but I believe that in this you're missing
> the vast majority (we hope) of PostgreSQL users. These are the users
> who have yet to adopt PostgreSQL, and have the quite reasonable
> expectation that ordinary-looking grammar *isn't* an optimization
> fence.
>

I am not in favor of seriously inconveniencing a significant number of
our existing users for the sake of a bunch of people who don't now and
might never in the future use Postgres. I think the bar for silent
behaviour changes needs to be a bit higher than this one is.

cheers

andrew

--
Andrew Dunstan https://www.2ndQuadrant.com
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