Function InventorySliceTree

src/backend/executor/execUtils.c:1911–1935

* Helper for AssignGangs takes a simple inventory of the gangs required * by a slice tree. Recursive. Closely coupled with AssignGangs. Not * generally useful. */

 * generally useful.
 */
static void
InventorySliceTree(CdbDispatcherState *ds, SliceTable *sliceTable, int sliceIndex)
{
	ExecSlice *slice = &sliceTable->slices[sliceIndex];
	ListCell *cell;

	if (slice->gangType == GANGTYPE_UNALLOCATED)
	{
		slice->primaryGang = NULL;
		slice->primaryProcesses = getCdbProcessesForQD(true);
	}
	else if (!slice->primaryGang)
	{
		Assert(slice->segments != NIL);
		slice->primaryGang = AllocateGang(ds, slice->gangType, slice->segments);
		setupCdbProcessList(slice);
	}

	foreach(cell, slice->children)
	{
		int			childIndex = lfirst_int(cell);

		InventorySliceTree(ds, sliceTable, childIndex);
	}
}

/*
 * Choose the execution identity (who does this executor serve?).