Re: Partitioned tables and relfilenode

On Fri, Mar 17, 2017 at 4:57 AM, Amit Langote
<Langote_Amit_f8@lab.ntt.co.jp> wrote:
>> Yes, but on the flip side, you're having to add code in a lot of
>> places -- I think I counted 7 -- where you turn around and ignore
>> those AppendRelInfos.
>
> Perhaps you were looking at the previous version with "minimal" appinfos
> containing the child_is_partitioned field?

Yes, I think I was.  I think this version looks a lot better.

     /*
+     * Close the root partitioned rel if we opened it above, but keep the
+     * lock.
+     */
+    if (rel != mtstate->resultRelInfo->ri_RelationDesc)
+        heap_close(rel, NoLock);

We didn't take a lock above, though, so drop everything in the comment
from "but" onward.

-    add_paths_to_append_rel(root, rel, live_childrels);
+    add_paths_to_append_rel(root, rel, live_childrels, partitioned_rels);

I think it would make more sense to put the new logic into
add_paths_to_append_rel, instead of passing this down as an additional
parameter.

+     * do not appear anywhere else in the plan.  Situation is exactly the

The situation is...

+    if (parent_rte->relkind == RELKIND_PARTITIONED_TABLE)
+    {
+        foreach(lc, root->pcinfo_list)
+        {
+            PartitionedChildRelInfo *pc = lfirst(lc);
+
+            if (pc->parent_relid == parentRTindex)
+            {
+                partitioned_rels = pc->child_rels;
+                break;
+            }
+        }
+    }

You seem to have a few copies of this logic.  I think it would be
worth factoring it out into a separate function.

+                root->glob->nonleafResultRelations =
+                    list_concat(root->glob->nonleafResultRelations,
+                                list_copy(splan->partitioned_rels));

Please add a brief comment.  One line is fine.

+            newrc->isParent = childrte->relkind == RELKIND_PARTITIONED_TABLE;

I'm not sure what project style is, but I personally find these kinds
of assignments easier to read with an extra set of parantheses:

            newrc->isParent = (childrte->relkind == RELKIND_PARTITIONED_TABLE);

+    if (partitioned_rels == NIL)
+        return;
+
+    foreach(lc, partitioned_rels)

I think the if-test is pointless; the foreach loop is going to start
by comparing the initial value with NIL.

Why doesn't ExecSerializePlan() need to transfer a proper value for
nonleafResultRelations to workers?  Seems like it should.

-- 
Robert Haas
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