RE: Hybrid Hash/Nested Loop joins and caching results from subplans

[houzj.f...@fujitsu.com]

> I've attached the updated patch.  I'll let the CFbot grab this to ensure it's
> happy with it before I go looking to push it again.

Hi,

I took a look into the patch and noticed some minor things.

1.
+               case T_ResultCache:
+                       ptype = "ResultCache";
+                       subpath = ((ResultCachePath *) path)->subpath;
+                       break;
                case T_UniquePath:
                        ptype = "Unique";
                        subpath = ((UniquePath *) path)->subpath;
should we use "case T_ResultCachePath" here?

2.
Is it better to add ResultCache's info to " src/backend/optimizer/README " ?
Something like:
  NestPath      - nested-loop joins
  MergePath     - merge joins
  HashPath      - hash joins
+ ResultCachePath - Result cache

Best regards,
Hou zhijie