Re: Ordered Partitioned Table Scans

On Thu, 28 Mar 2019 at 14:34, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
>
> On 2019/03/28 7:29, David Rowley wrote:
> > On Wed, 27 Mar 2019 at 19:48, Amit Langote
> > It does need to know how many partitions the partitioned table has,
> > which it gets from partrel->nparts, so yeah, RelOptInfo is probably
> > needed. I don't think passing in int nparts is a good solution to
> > that. The problem with moving it to partbounds.c is that nothing
> > there knows about RelOptInfo currently.
>
> Maybe, this could be a start. Also, there is a patch in nearby thread
> which adds additional functionality to partbounds.c to be used by
> partitionwise join code in the optimizer [1].

Thanks for the review. I've attached a patch that mostly just moved
the code around.

I also changed the comment in build_partition_pathkeys() to explain
about the nulls_first argument and why I just pass
ScanDirectionIsBackward(scandir).

Also, another comment in struct PlannerInfo to mentioning the
guarantee about append_rel_list having earlier partitions as defined
in PartitionDesc earlier in the list.

--
David Rowley http://www.2ndQuadrant.com/
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