diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index 49d1c9d2bb9..c861226fbcd 100644
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -577,7 +577,7 @@ getNextNearest(IndexScanDesc scan)
 					if (!scan->xs_orderbynulls[i])
 						pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
 #endif
-					scan->xs_orderbyvals[i] = item->distances[i].value;
+					scan->xs_orderbyvals[i] = Float8GetDatum(item->distances[i].value);
 					scan->xs_orderbynulls[i] = item->distances[i].isnull;
 				}
 				else if (so->orderByTypes[i] == FLOAT4OID)