Re: Patch to add functionality to specify ORDER BY in CREATE FUNCTION for SRFs

On 06-01-2015 PM 04:08, Atri Sharma wrote:
> On Tue, Jan 6, 2015 at 12:29 PM, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp


I read what Ashutosh says as that a clause like IMMUTABLE does not
entail a node execution. Reading manual for CREATE FUNCTION:

<manual>
IMMUTABLE
STABLE
VOLATILE

These attributes inform the query optimizer about the behavior of the
function.
</manual>

They declare the shape of the kind of output the function produces and
planner simply trusts the declaration meaning it does not add a node to
check if, say, an IMMUTABLE function did not actually modify the
database or that it is returning the same output for a given input.

Though, I have no strong opinion on whether one thing is good or the
other or whether they cover some particular use case all the same.
Perhaps you can say that better.