diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 4e4a0ccbefb..7d0877c95ec 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -3339,12 +3339,12 @@ check_autovacuum_work_mem(int *newval, void **extra, GucSource source)
 		return true;
 
 	/*
-	 * We clamp manually-set values to at least 1MB.  Since
+	 * We clamp manually-set values to at least 64kB.  Since
 	 * maintenance_work_mem is always set to at least this value, do the same
 	 * here.
 	 */
-	if (*newval < 1024)
-		*newval = 1024;
+	if (*newval < 64)
+		*newval = 64;
 
 	return true;
 }
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index c0a52cdcc3e..289dea7878a 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -2510,6 +2510,11 @@ struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+	/*
+	 * Dynamic shared memory has a higher overhead than local memory contexts,
+	 * so when testing low-memory scenarios that could use shared memory, the
+	 * recommended minimum is 1MB.
+	 */
 	{
 		{"maintenance_work_mem", PGC_USERSET, RESOURCES_MEM,
 			gettext_noop("Sets the maximum memory to be used for maintenance operations."),
@@ -2517,7 +2522,7 @@ struct config_int ConfigureNamesInt[] =
 			GUC_UNIT_KB
 		},
 		&maintenance_work_mem,
-		65536, 1024, MAX_KILOBYTES,
+		65536, 64, MAX_KILOBYTES,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 9ec9f97e926..667e0dc40a2 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -139,8 +139,8 @@
 # you actively intend to use prepared transactions.
 #work_mem = 4MB				# min 64kB
 #hash_mem_multiplier = 2.0		# 1-1000.0 multiplier on hash table work_mem
-#maintenance_work_mem = 64MB		# min 1MB
-#autovacuum_work_mem = -1		# min 1MB, or -1 to use maintenance_work_mem
+#maintenance_work_mem = 64MB		# min 64kB
+#autovacuum_work_mem = -1		# min 64kB, or -1 to use maintenance_work_mem
 #logical_decoding_work_mem = 64MB	# min 64kB
 #max_stack_depth = 2MB			# min 100kB
 #shared_memory_type = mmap		# the default is the first option