SERVER-19375 choose new sync source based on last fetched op rather than last applied op

also change chooseNewSyncSource to take a Timestamp rather than an OpTime

1 files changed, 3 insertions, 2 deletions

diff --git a/src/mongo/db/repl/oplogreader.cpp b/src/mongo/db/repl/oplogreader.cpp
index 950517d6192..e363767ec05 100644
--- a/src/mongo/db/repl/oplogreader.cpp
+++ b/src/mongo/db/repl/oplogreader.cpp
@@ -147,7 +147,7 @@ void OplogReader::connectToSyncSource(OperationContext* txn,
     invariant(conn() == NULL);
 
     while (true) {
-        HostAndPort candidate = replCoord->chooseNewSyncSource();
+        HostAndPort candidate = replCoord->chooseNewSyncSource(lastOpTimeFetched.getTimestamp());
 
         if (candidate.empty()) {
             if (oldestOpTimeSeen == sentinel) {
@@ -186,7 +186,8 @@ void OplogReader::connectToSyncSource(OperationContext* txn,
         OpTime remoteOldOpTime = extractOpTime(remoteOldestOp);
 
         // remoteOldOpTime may come from a very old config, so we cannot compare their terms.
-        if (lastOpTimeFetched.getTimestamp() < remoteOldOpTime.getTimestamp()) {
+        if (!lastOpTimeFetched.isNull() &&
+            lastOpTimeFetched.getTimestamp() < remoteOldOpTime.getTimestamp()) {
             // We're too stale to use this sync source.
             resetConnection();
             replCoord->blacklistSyncSource(candidate, Date_t::now() + Minutes(10));