1 files changed, 42 insertions, 0 deletions
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 6b370750c5b..63de981034d 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -1009,6 +1009,17 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
  * of initplans: we don't run the subplan until/unless we need its output.
  * Note that this routine MUST clear the execPlan fields of the plan's
  * output parameters after evaluating them!
+ *
+ * The results of this function are stored in the EState associated with the
+ * ExprContext (particularly, its ecxt_param_exec_vals); any pass-by-ref
+ * result Datums are allocated in the EState's per-query memory.  The passed
+ * econtext can be any ExprContext belonging to that EState; which one is
+ * important only to the extent that the ExprContext's per-tuple memory
+ * context is used to evaluate any parameters passed down to the subplan.
+ * (Thus in principle, the shorter-lived the ExprContext the better, since
+ * that data isn't needed after we return.  In practice, because initplan
+ * parameters are never more complex than Vars, Aggrefs, etc, evaluating them
+ * currently never leaks any memory anyway.)
  * ----------------------------------------------------------------
  */
 void
@@ -1196,6 +1207,37 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 }
 
 /*
+ * ExecSetParamPlanMulti
+ *
+ * Apply ExecSetParamPlan to evaluate any not-yet-evaluated initplan output
+ * parameters whose ParamIDs are listed in "params".  Any listed params that
+ * are not initplan outputs are ignored.
+ *
+ * As with ExecSetParamPlan, any ExprContext belonging to the current EState
+ * can be used, but in principle a shorter-lived ExprContext is better than a
+ * longer-lived one.
+ */
+void
+ExecSetParamPlanMulti(const Bitmapset *params, ExprContext *econtext)
+{
+	int			paramid;
+
+	paramid = -1;
+	while ((paramid = bms_next_member(params, paramid)) >= 0)
+	{
+		ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
+
+		if (prm->execPlan != NULL)
+		{
+			/* Parameter not evaluated yet, so go do it */
+			ExecSetParamPlan(prm->execPlan, econtext);
+			/* ExecSetParamPlan should have processed this param... */
+			Assert(prm->execPlan == NULL);
+		}
+	}
+}
+
+/*
  * Mark an initplan as needing recalculation
  */
 void