On 2017/08/02 15:21, Amit Langote wrote:
Thanks Fuita-san and Amit for reviewing.

On 2017/08/02 1:33, Amit Khandekar wrote:
On 1 August 2017 at 15:11, Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote:
On 2017/07/31 18:56, Amit Langote wrote:
Yes, that's what's needed here.  So we need to teach
map_variable_attnos_mutator() to convert whole-row vars just like it's
done in adjust_appendrel_attrs_mutator().

Seems reasonable.  (Though I think it might be better to do this kind of
conversion in the planner, not the executor, because that would increase the
efficiency of cached plans.)

That's a good point, although it sounds like a bigger project that, IMHO,
should be undertaken separately, because that would involve designing for
considerations of expanding inheritance even in the INSERT case.

Agreed.  I think that would be definitely a material for PG11.

I think the work of shifting to planner should be taken as a different
task when we shift the preparation of DispatchInfo to the planner.

Yeah, I think it'd be a good idea to do those projects together.  That is,
doing what Fujita-san suggested and expanding partitioned tables in
partition bound order in the planner.



Few more comments :

@@ -1240,7 +1247,7 @@ map_variable_attnos_mutator(Node *node,
  var->varlevelsup == context->sublevels_up)
  /* Found a matching variable, make the substitution */

- Var                *newvar = (Var *) palloc(sizeof(Var));
+ Var                *newvar = copyObject(var);
   int                     attno = var->varattno;

  *newvar = *var;

Here, "*newvar = *var" should be removed.


I'm not sure this change is a good idea, because the copy by "*newvar = *var" would be more efficient than the copyObject(). (We have this optimization in other places as well. See eg, copyVar() in setrefs.c.)

Here are some other comments:

+                               /* If the callers expects us to convert the 
same, do so. */
+                               if (OidIsValid(context->to_rowtype))
+                               {
+                                       ConvertRowtypeExpr *r;
+                                       /* Var itself is converted to the 
requested rowtype. */
+                                       newvar->vartype = context->to_rowtype;
+                                       /*
+                                        * And a conversion step on top to 
convert back to the
+                                        * original type.
+                                        */
+                                       r = makeNode(ConvertRowtypeExpr);
+                                       r->arg = (Expr *) newvar;
+                                       r->resulttype = var->vartype;
+                                       r->convertformat = COERCE_IMPLICIT_CAST;
+                                       r->location = -1;
+                                       return (Node *) r;
+                               }

Why not do this conversion if to_rowtype is valid and it's different from the rowtype of the original whole-row Var like the previous patch? Also, I think it's better to add an assertion that the rowtype of the original whole-row Var is a named one. So, what I have in mind is:

  if (OidIsValid(context->to_rowtype))
    Assert(var->vartype != RECORDOID)
    if (var->vartype != context->to_rowtype)
      ConvertRowtypeExpr *r;

      /* Var itself is converted to the requested rowtype. */
      /* And a conversion step on top to convert back to the ... */
      return (Node *) r;

Here is the modification to the map_variable_attnos()'s API:

 map_variable_attnos(Node *node,
                                        int target_varno, int sublevels_up,
const AttrNumber *attno_map, int map_length,
-                                       bool *found_whole_row)
+ bool *found_whole_row, Oid to_rowtype)

This is nitpicking, but I think it would be better to put the new argument to_rowtype right before the output argument found_whole_row.

+ * RelationGetRelType
+ *             Returns the rel's pg_type OID.
+ */
+#define RelationGetRelType(relation) \
+       ((relation)->rd_rel->reltype)

This macro is used in only one place. Do we really need that? (This macro would be useful for other places such as expand_inherited_rtentry, but I think it's better to introduce this in a separate patch, maybe for PG11.)

+-- check that wholerow vars in the RETUNING list work with partitioned tables


Sorry for the delay.

Best regards,
Etsuro Fujita

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