diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/nodes/relation.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h index 6e003765e04..c2274bf48ce 100644 --- a/src/include/nodes/relation.h +++ b/src/include/nodes/relation.h @@ -1318,12 +1318,17 @@ typedef struct PlaceHolderInfo * * Each paramlist item shows the absolute query level it is associated with, * where the outermost query is level 1 and nested subqueries have higher - * numbers. The item the parameter slot represents can be one of three kinds: + * numbers. The item the parameter slot represents can be one of four kinds: * * A Var: the slot represents a variable of that level that must be passed * down because subqueries have outer references to it. The varlevelsup * value in the Var will always be zero. * + * A PlaceHolderVar: this works much like the Var case, except that the + * entry is a PlaceHolderVar node with a contained expression. The PHV + * will have phlevelsup = 0, and the contained expression is adjusted + * to match in level. + * * An Aggref (with an expression tree representing its argument): the slot * represents an aggregate expression that is an outer reference for some * subquery. The Aggref itself has agglevelsup = 0, and its argument tree @@ -1333,14 +1338,14 @@ typedef struct PlaceHolderInfo * for that subplan). The absolute level shown for such items corresponds * to the parent query of the subplan. * - * Note: we detect duplicate Var parameters and coalesce them into one slot, - * but we do not do this for Aggref or Param slots. + * Note: we detect duplicate Var and PlaceHolderVar parameters and coalesce + * them into one slot, but we do not do this for Aggref or Param slots. */ typedef struct PlannerParamItem { NodeTag type; - Node *item; /* the Var, Aggref, or Param */ + Node *item; /* the Var, PlaceHolderVar, Aggref, or Param */ Index abslevel; /* its absolute query level */ } PlannerParamItem; |