SERVER-29270 Oplog query for first/last entry should not use a blocking sort

(cherry picked from commit 3e8b9c599f3027778b48e8c3235d676134eef9bb)

1 files changed, 1 insertions, 1 deletions

diff --git a/jstests/noPassthroughWithMongod/initial_sync_oplog_rollover.js b/jstests/noPassthroughWithMongod/initial_sync_oplog_rollover.js
index 3a47e14447c..d186a8f59ec 100644
--- a/jstests/noPassthroughWithMongod/initial_sync_oplog_rollover.js
+++ b/jstests/noPassthroughWithMongod/initial_sync_oplog_rollover.js
@@ -34,7 +34,7 @@
     assert.writeOK(coll.insert({a: 1}));
 
     function getFirstOplogEntry(conn) {
-        return conn.getDB('local').oplog.rs.find().sort({ts: 1}).limit(1)[0];
+        return conn.getDB('local').oplog.rs.find().sort({$natural: 1}).limit(1)[0];
     }
 
     var firstOplogEntry = getFirstOplogEntry(primary);