diff --git a/src/backend/utils/time/sharedsnapshot.c b/src/backend/utils/time/sharedsnapshot.c
index e89dfe2136b3382c48a4de55979ab36c16273223..7d83d98ef8aae78b6be43d24e60f0911e797f374 100644
--- a/src/backend/utils/time/sharedsnapshot.c
+++ b/src/backend/utils/time/sharedsnapshot.c
@@ -226,10 +226,16 @@ SharedSnapshotShmemSize(void)
 	slotSize = MAXALIGN(slotSize);
 
 	/*
-	 * We only really need max_prepared_xacts; but for safety we
-	 * multiply that by two (to account for slow de-allocation on
-	 * cleanup, for instance).
+	 * We only really need MaxBackends; but for safety we multiply that by two
+	 * (to account for slow de-allocation on cleanup, for instance).
+	 *
+	 * MaxBackends is only somewhat right.  What we really want here is the
+	 * MaxBackends value from the QD.  But this is at least safe since we know
+	 * we dont need *MORE* than MaxBackends.  But in general MaxBackends on a
+	 * QE is going to be bigger than on a QE by a good bit.  or at least it
+	 * should be.
 	 */
+
 	slotCount = NUM_SHARED_SNAPSHOT_SLOTS;
 
 	size = offsetof(SharedSnapshotStruct, xips);
@@ -263,18 +269,7 @@ CreateSharedSnapshotArray(void)
 		 */
 		sharedSnapshotArray->numSlots = 0;
 
-		/* TODO:  MaxBackends is only somewhat right.  What we really want here
-		 *        is the MaxBackends value from the QD.  But this is at least
-		 *		  safe since we know we dont need *MORE* than MaxBackends.  But
-		 *        in general MaxBackends on a QE is going to be bigger than on a
-		 *		  QE by a good bit.  or at least it should be.
-		 *
-		 * But really, max_prepared_transactions *is* what we want (it
-		 * corresponds to the number of connections allowed on the
-		 * master).
-		 *
-		 * slotCount is initialized in SharedSnapshotShmemSize().
-		 */
+		/* slotCount is initialized in SharedSnapshotShmemSize(). */
 		sharedSnapshotArray->maxSlots = slotCount;
 		sharedSnapshotArray->nextSlot = 0;
 
diff --git a/src/backend/utils/time/test/sharedsnapshot_test.c b/src/backend/utils/time/test/sharedsnapshot_test.c
index 29d6a9f936dcb8070143f8dbcbce4fadb281aefc..259899684a0b7d49db486ad479ed4bd3270aa5e2 100644
--- a/src/backend/utils/time/test/sharedsnapshot_test.c
+++ b/src/backend/utils/time/test/sharedsnapshot_test.c
@@ -100,10 +100,10 @@ static void
 test_boundaries_of_CreateSharedSnapshotArray(void **state)
 {
 	/*
-	 * max_prepared_xacts is used to calculate NUM_SHARED_SNAPSHOT_SLOTS. Make
+	 * MaxBackends is used to calculate NUM_SHARED_SNAPSHOT_SLOTS. Make
 	 * it non-zero so that we actually allocate some local snapshot slots.
 	 */
-	max_prepared_xacts = 2;
+	MaxBackends = 2;
 
 	SharedSnapshotStruct *fakeSharedSnapshotArray = NULL;
 
diff --git a/src/include/utils/sharedsnapshot.h b/src/include/utils/sharedsnapshot.h
index 58fda9cf85b3822d469598c7023fd332b89b2471..22f7c378fb40643b7a1983e587d2f0b1a9f421fe 100644
--- a/src/include/utils/sharedsnapshot.h
+++ b/src/include/utils/sharedsnapshot.h
@@ -53,6 +53,6 @@ extern void readSharedLocalSnapshot_forCursor(Snapshot snapshot, DtxContext dist
 
 extern void AtEOXact_SharedSnapshot(void);
 
-#define NUM_SHARED_SNAPSHOT_SLOTS (2 * max_prepared_xacts)
+#define NUM_SHARED_SNAPSHOT_SLOTS (2 * MaxBackends)
 
 #endif   /* SHAREDSNAPSHOT_H */