Amit Langote wrote:
> On 2018/04/24 6:10, Alvaro Herrera wrote:
> > Not really sure how best to handle that one. For starters, I think it need
> > to stop mentioning the GUC name in the title;
>
> Hmm, "Constraint Exclusion" that's used in the title is a concept, not a
> GUC, although pretty close.
Yeah, I meant that if we want that section to cover the general concept
of partition pruning, with either technique, better not use the words
"constraint exclusion" in the title.
> > maybe rename it to
> > "Partition Pruning" or some such, and then in the text explain that
> > sometimes the enable_partition_pruning param is used in one case and
> > constraint_exclusion in the other, and approximately what effects they
> > have. I don't think it's worth going into too much detail on exactly
> > how they differ, but then I'm not 100% sure of that either.
>
> Just a thought -- How about making 5.10.4 cover partitioning based
> optimizations in general? I see that a number of partitioning-based
> optimizations have been developed in this release cycle, but I only see
> various enable_partition* GUCs listed in config.sgml and not much else.
I think we should not rely on the config.sgml blurbs exclusively; some
narrative is always welcome -- except that for planner enable_* settings
I'm not sure we really need all that much text after all. Constraint
exclusion was pretty easy to get wrong, hence the need for a separate
section, and I suppose the new partition pruning may be prey to the same
problems, so it seems worth to document them specially. But not sure
about the others, if they are mostly debugging tools.
> Although the config.sgml coverage of the new capabilities seems pretty
> good, some may find their being mentioned in 5.10 Table Partitioning
> helpful. Or if we don't want to hijack 5.10.4, maybe create a 5.10.5.
Can you (or someone) describe what would that section contain?
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
