RE: speeding up planning with partitions

Amit-san,

On Thu, Feb 7, 2019 at 10:22 AM, Amit Langote wrote:
> Rebased over bdd9a99aac.

I did code review of 0001 and I have some suggestions. Could you check them?

1.
0001: line 418
+ * add_inherit_target_child_root() would've added only those that are

add_inherit_target_child_root() doesn't exist now, so an above comment needs to be modified.

2.
0001: line 508-510

In set_inherit_target_rel_pathlists():
+ /* Nothing to do if all the children were excluded. */
+ if (IS_DUMMY_REL(rel))
+ return;

These codes aren't needed or can be replaced by Assert because set_inherit_target_rel_pathlists is only called from set_rel_pathlist which excutes IS_DUMMY_REL(rel) before calling set_inherit_target_rel_pathlists, as follows.

set_rel_pathlist(...)
{
...
if (IS_DUMMY_REL(rel))
{
/* We already proved the relation empty, so nothing more to do */
}
else if (rte->inh)
{
/*
* If it's a target relation, set the pathlists of children instead.
* Otherwise, we'll append the outputs of children, so process it as
* an "append relation".
*/
if (root->inherited_update && root->parse->resultRelation == rti)
{
inherited_update = true;
set_inherit_target_rel_pathlists(root, rel, rti, rte);

3.
0001: line 1919-1920

- case CONSTRAINT_EXCLUSION_ON:
- break; /* always try to exclude */

CONSTRAINT_EXCLUSION_ON is no longer used, so should we remove it also from guc parameters?

4.
0001:

Can we remove enum InheritanceKind which is no longer used?

I also see the patch from a perspective of separating codes from 0001 which are not essential of Overhaul inheritance update/delete planning. Although almost all of codes are related each other, but I found below two things can be moved to another patch.

---
0001: line 550-608

This section seems to be just refinement of set_append_rel_size().
So can we separate this from 0001 to another patch?

---
0001: line 812-841, 940-947, 1525-1536, 1938-1947

These codes are related to removement of InheritanceKind from relation_excluded_by_constraints(), so I think it is something like cleaning of unneeded codes. Can we separate this to patch as some-code-clearnups-of-0001.patch? Of course, we can do that only if removing of these codes from 0001 would not bother success of "make check" of 0001.
I also think that what I pointed out at above 3. and 4. can also be included in some-code-clearnups-of-0001.patch.

What do you think?

--
Yoshikazu Imai