Re: PG 12 draft release notes

On Tue, May 21, 2019 at 05:00:31PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > On Mon, May 20, 2019 at 08:48:15PM -0400, Tom Lane wrote:
> >> Yes, this should be in "source code". I think it should be merged
> >> with a391ff3c and 74dfe58a into something like
> >>
> >> Allow extensions to create planner support functions that
> >> can provide function-specific selectivity, cost, and
> >> row-count estimates that can depend on the function arguments.
> >> Support functions can also transform WHERE clauses involving
> >> an extension's functions and operators into indexable clauses
> >> in ways that the core code cannot for lack of detailed semantic
> >> knowledge of those functions/operators.
>
> > The new text is:
>
> > Add support function capability to improve optimizer estimates
> > for functions (Tom Lane)
>
> > This allows extensions to create planner support functions that
> > can provide function-specific selectivity, cost, and row-count
> > estimates that can depend on the function arguments. Also, improve
> > in-core estimates for <function>generate_series()</function>,
> > <function>unnest()</function>, and functions that return boolean
> > values.
>
> Uh ... you completely lost the business about custom indexable clauses.
> I agree with Andres that that's the most important aspect of this.

Oh, I see what you mean now. I have updated the docs and moved the item
to Source Code:

<para>
Add support function capability to improve optimizer estimates,
inlining, and indexing for functions (Tom Lane)
</para>

<para>
This allows extensions to create planner support functions that
can provide function-specific selectivity, cost, and row-count
estimates that can depend on the function's arguments. Support
functions can also supply simplified representations and index
conditions, greatly expanding optimization possibilities.
</para>

> > Notice that there are some improvments in in-core functions. Should this
> > still be moved to the source code section?
>
> I doubt that that's worth mentioning at all. It certainly isn't a
> reason not to move this to the source-code section, because that's
> where we generally put things that are of interest for improving
> extensions, which is what this mainly is.

In-core function mention removed.

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Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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