diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 4f60b85..2886219 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -23,6 +23,7 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_proc.h"
 #include "foreign/fdwapi.h"
+#include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
 #ifdef OPTIMIZER_DEBUG
@@ -678,7 +679,7 @@ create_parallel_paths(PlannerInfo *root, RelOptInfo *rel)
 	 * need something here for now.
 	 */
 	while (rel->pages > parallel_threshold * 3 &&
-		   parallel_degree < max_parallel_degree)
+		   parallel_degree < Min(max_parallel_degree, max_worker_processes))
 	{
 		parallel_degree++;
 		parallel_threshold *= 3;
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 773b4e8..00368bb 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -163,7 +163,8 @@
 # - Asynchronous Behavior -

 #effective_io_concurrency = 1		# 1-1000; 0 disables prefetching
-#max_worker_processes = 8
+#max_worker_processes = 8       # max number of background workers
+                    #(change requires restart)
 #max_parallel_degree = 0		# max number of worker processes per node