diff options
Diffstat (limited to 'src/backend/optimizer/plan/subselect.c')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index 0849b1d5634..a46cc108203 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -2187,7 +2187,7 @@ SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel) * * Attach any initplans created in the current query level to the specified * plan node, which should normally be the topmost node for the query level. - * (The initPlans could actually go in any node at or above where they're + * (In principle the initPlans could go in any node at or above where they're * referenced; but there seems no reason to put them any lower than the * topmost node, so we don't bother to track exactly where they came from.) * We do not touch the plan node's cost; the initplans should have been @@ -2226,9 +2226,22 @@ SS_finalize_plan(PlannerInfo *root, Plan *plan) * recursion. * * The return value is the computed allParam set for the given Plan node. - * This is just an internal notational convenience. + * This is just an internal notational convenience: we can add a child + * plan's allParams to the set of param IDs of interest to this level + * in the same statement that recurses to that child. * * Do not scribble on caller's values of valid_params or scan_params! + * + * Note: although we attempt to deal with initPlans anywhere in the tree, the + * logic is not really right. The problem is that a plan node might return an + * output Param of its initPlan as a targetlist item, in which case it's valid + * for the parent plan level to reference that same Param; the parent's usage + * will be converted into a Var referencing the child plan node by setrefs.c. + * But this function would see the parent's reference as out of scope and + * complain about it. For now, this does not matter because the planner only + * attaches initPlans to the topmost plan node in a query level, so the case + * doesn't arise. If we ever merge this processing into setrefs.c, maybe it + * can be handled more cleanly. */ static Bitmapset * finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params, |