Function ExecParallelEstimate

src/backend/executor/execParallel.c:232–308

* Parallel-aware plan nodes (and occasionally others) may need some state * which is shared across all parallel workers. Before we size the DSM, give * them a chance to call shm_toc_estimate_chunk or shm_toc_estimate_keys on * &pcxt->estimator. * * While we're at it, count the number of PlanState nodes in the tree, so * we know how many Instrumentation structures we need. */

 * we know how many Instrumentation structures we need.
 */
static bool
ExecParallelEstimate(PlanState *planstate, ExecParallelEstimateContext *e)
{
	if (planstate == NULL)
		return false;

	/* Count this node. */
	e->nnodes++;

	switch (nodeTag(planstate))
	{
		case T_SeqScanState:
			if (planstate->plan->parallel_aware)
				ExecSeqScanEstimate((SeqScanState *) planstate,
									e->pcxt);
			break;
		case T_IndexScanState:
			if (planstate->plan->parallel_aware)
				ExecIndexScanEstimate((IndexScanState *) planstate,
									  e->pcxt);
			break;
		case T_IndexOnlyScanState:
			if (planstate->plan->parallel_aware)
				ExecIndexOnlyScanEstimate((IndexOnlyScanState *) planstate,
										  e->pcxt);
			break;
		case T_ForeignScanState:
			if (planstate->plan->parallel_aware)
				ExecForeignScanEstimate((ForeignScanState *) planstate,
										e->pcxt);
			break;
		case T_AppendState:
			if (planstate->plan->parallel_aware)
				ExecAppendEstimate((AppendState *) planstate,
								   e->pcxt);
			break;
		case T_CustomScanState:
			if (planstate->plan->parallel_aware)
				ExecCustomScanEstimate((CustomScanState *) planstate,
									   e->pcxt);
			break;
		case T_BitmapHeapScanState:
			if (planstate->plan->parallel_aware)
				ExecBitmapHeapEstimate((BitmapHeapScanState *) planstate,
									   e->pcxt);
			break;
		case T_HashJoinState:
			if (planstate->plan->parallel_aware)
				ExecHashJoinEstimate((HashJoinState *) planstate,
									 e->pcxt);
			break;
		case T_HashState:
			/* even when not parallel-aware, for EXPLAIN ANALYZE */
			ExecHashEstimate((HashState *) planstate, e->pcxt);
			break;
		case T_SortState:
			/* even when not parallel-aware, for EXPLAIN ANALYZE */
			ExecSortEstimate((SortState *) planstate, e->pcxt);