diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6098f6b020..a7281c8e73 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1893,6 +1893,11 @@ include_dir 'conf.d'
         too high.  It may be useful to control for this by separately
         setting <xref linkend="guc-autovacuum-work-mem"/>.
        </para>
+       <para>
+        Additionally, <command>VACUUM</command> is only able to utilize up to
+        a maximum of 1GB of memory, so <varname>maintenance_work_mem</varname>
+        values higher than this have no effect on <command>VACUUM</command>.
+       </para>
       </listitem>
      </varlistentry>
 
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 480e8cd199..bb76baa72d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3340,7 +3340,8 @@ static struct config_int ConfigureNamesInt[] =
 			GUC_UNIT_KB
 		},
 		&autovacuum_work_mem,
-		-1, -1, MAX_KILOBYTES,
+		/* see compute_max_dead_tuples if you need to change the max value */
+		-1, -1, 1024 * 1024,
 		check_autovacuum_work_mem, NULL, NULL
 	},