Re: speeding up planning with partitions

On 2019/02/02 22:52, Amit Langote wrote:
> Attached updated patches.
>
> One big change is related to how ECs are transferred to child
> PlannerInfos. As David suggested upthread, I created a block in
> adjust_appendrel_attrs_mutator that creates a translated copy of a
> given EC containing wherein the parent expression in the original
> ec_members list is replaced by the corresponding child expression.
> With that in place, we no longer need the changes to
> add_child_rel_equivalences(). Instead there's just:
> subroot->eq_classes = adjust_appendrel_attrs(root, root->eq_classes,
> ...), just as David described upthread.

Rebased over bdd9a99aac.

That commit fixes the bug that lateral_relids were not propagated to
grandchildren of an appendrel in some cases due to the way parent rels
were mapped to child rels in a nested loop over root->simple_rel_array and
root->append_rel_list. The problem that was fixed with that commit was
not present with the patches here to begin with. With the patch 0002
here, lateral_relids are propagated from parent rel to child rel directly
when the latter's RelOptInfo is built, so lateral_relids are properly
propagated from the (possibly RTE_SUBQUERY) top-most parent rel to all the
child rels.

Thanks,
Amit