Revert "SERVER-33248 Allow choosing a sync source that we are up to date with if it has a higher lastOpCommitted"

This reverts commit 5df9e94b0c4840680d1d17fcf2f04412cf6d70cf.

17 files changed, 150 insertions, 319 deletions

diff --git a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
index 6ada79e5ca0..8eaa08c3f36 100644
--- a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
@@ -136,6 +136,10 @@ selector:
   - jstests/core/explain_upsert.js
   # The `dbstats` command builds in-memory structures that are not causally consistent.
   - jstests/core/dbstats.js
+  # TODO SERVER-33248: Remove this test from the blacklist. The secondary can get stuck without a
+  # sync source if the RestartCatalog command kills its oplog fetching cursor, which blocks
+  # secondary majority reads.
+  - jstests/core/restart_catalog.js
   exclude_with_any_tags:
   - assumes_against_mongod_not_mongos
   ##
diff --git a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
index 1a94d618226..bbe744b2286 100644
--- a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
+++ b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
@@ -154,6 +154,10 @@ selector:
   - jstests/core/explain_upsert.js
   # The `dbstats` command builds in-memory structures that are not causally consistent.
   - jstests/core/dbstats.js
+  # TODO SERVER-33248: Remove this test from the blacklist. The secondary can get stuck without a
+  # sync source if the RestartCatalog command kills its oplog fetching cursor, which blocks
+  # secondary majority reads.
+  - jstests/core/restart_catalog.js
 
   # These include operations the root user auth'd on the test database is not authorized to perform,
   # e.g. dropping or creating system collections.
diff --git a/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
index b3ae37b1873..aa24ddbc2ef 100644
--- a/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
@@ -176,6 +176,10 @@ selector:
   - jstests/core/orf.js #explain.executionStats is not CC
   # The `dbstats` command builds in-memory structures that are not causally consistent.
   - jstests/core/dbstats.js
+  # TODO SERVER-33248: Remove this test from the blacklist. The secondary can get stuck without a
+  # sync source if the RestartCatalog command kills its oplog fetching cursor, which blocks
+  # secondary majority reads.
+  - jstests/core/restart_catalog.js
   exclude_with_any_tags:
   # Tests tagged with the following will fail because they assume collections are not sharded.
   - assumes_no_implicit_collection_creation_after_drop
diff --git a/buildscripts/resmokelib/testing/fixtures/replicaset.py b/buildscripts/resmokelib/testing/fixtures/replicaset.py
index 5f5e1568e4a..eaaf7463594 100644
--- a/buildscripts/resmokelib/testing/fixtures/replicaset.py
+++ b/buildscripts/resmokelib/testing/fixtures/replicaset.py
@@ -273,13 +273,21 @@ class ReplicaSetFixture(interface.ReplFixture):  # pylint: disable=too-many-inst
         primary_client = self.nodes[0].mongo_client()
         self.auth(primary_client, self.auth_options)
 
-        # All nodes must be in primary/secondary state prior to this point. Perform a majority
-        # write to ensure there is a committed operation on the set. The commit point will
-        # propagate to all members and trigger a stable checkpoint on all persisted storage engines
-        # nodes.
+        # Algorithm precondition: All nodes must be in primary/secondary state.
+        #
+        # 1) Perform a majority write. This will guarantee the primary updates its commit point
+        #    to the value of this write.
+        #
+        # 2) Perform a second write. This will guarantee that all nodes will update their commit
+        #    point to a time that is >= the previous write. That will trigger a stable checkpoint
+        #    on all nodes.
+        # TODO(SERVER-33248): Remove this block. We should not need to prod the replica set to
+        # advance the commit point if the commit point being lagged is sufficient to choose a
+        # sync source.
         admin = primary_client.get_database(
             "admin", write_concern=pymongo.write_concern.WriteConcern(w="majority"))
-        admin.command("appendOplogNote", data={"await_stable_recovery_timestamp": 1})
+        admin.command("appendOplogNote", data={"await_stable_checkpoint": 1})
+        admin.command("appendOplogNote", data={"await_stable_checkpoint": 2})
 
         for node in self.nodes:
             self.logger.info("Waiting for node on port %d to have a stable checkpoint.", node.port)
diff --git a/jstests/libs/override_methods/check_uuids_consistent_across_cluster.js b/jstests/libs/override_methods/check_uuids_consistent_across_cluster.js
index 6412b894ebd..0a05e19b25c 100644
--- a/jstests/libs/override_methods/check_uuids_consistent_across_cluster.js
+++ b/jstests/libs/override_methods/check_uuids_consistent_across_cluster.js
@@ -47,6 +47,11 @@ ShardingTest.prototype.checkUUIDsConsistentAcrossCluster = function() {
                 continue;
             }
             var rs = this._rs[i].test;
+            // The noop writer needs to be enabled in case a sync source isn't set, so that
+            // awaitLastOpCommitted() is guaranteed to finish.
+            // SERVER-33248 for reference.
+            rs.getPrimary().adminCommand({setParameter: 1, periodicNoopIntervalSecs: 1});
+            rs.getPrimary().adminCommand({setParameter: 1, writePeriodicNoops: true});
             var keyFile = this._otherParams.keyFile;
             if (keyFile) {
                 authutil.asCluster(rs.nodes, keyFile, function() {
diff --git a/jstests/noPassthrough/readConcern_atClusterTime_snapshot_selection.js b/jstests/noPassthrough/readConcern_atClusterTime_snapshot_selection.js
index a9a5bc022b7..7bcb38f93a0 100644
--- a/jstests/noPassthrough/readConcern_atClusterTime_snapshot_selection.js
+++ b/jstests/noPassthrough/readConcern_atClusterTime_snapshot_selection.js
@@ -29,10 +29,20 @@
     // Create the collection and insert one document. Get the op time of the write.
     let res = assert.commandWorked(primaryDB.runCommand(
         {insert: collName, documents: [{_id: "before"}], writeConcern: {w: "majority"}}));
-    const clusterTimePrimaryBefore = res.opTime.ts;
+    let clusterTimePrimaryBefore;
 
     // Wait for the majority commit point on 'secondaryDB0' to include the {_id: "before"} write.
     assert.soonNoExcept(function() {
+        // Without a consistent stream of writes, secondary majority reads are not guaranteed
+        // to complete, since the commit point being stale is not sufficient to establish a sync
+        // source.
+        // TODO (SERVER-33248): Remove this write and increase the maxTimeMS on the read.
+        res = assert.commandWorked(primaryDB.runCommand(
+            {insert: "otherColl", documents: [{a: 1}], writeConcern: {w: "majority"}}));
+        assert(res.hasOwnProperty("opTime"), tojson(res));
+        assert(res.opTime.hasOwnProperty("ts"), tojson(res));
+        clusterTimePrimaryBefore = res.opTime.ts;
+
         return assert
                    .commandWorked(secondaryDB0.runCommand(
                        {find: collName, readConcern: {level: "majority"}, maxTimeMS: 10000}))
diff --git a/jstests/replsets/dbhash_at_cluster_time.js b/jstests/replsets/dbhash_at_cluster_time.js
index 8c52ab741db..27f4e0f79db 100644
--- a/jstests/replsets/dbhash_at_cluster_time.js
+++ b/jstests/replsets/dbhash_at_cluster_time.js
@@ -19,6 +19,17 @@
     const db = session.getDatabase("test");
     let txnNumber = 0;
 
+    // We force 'secondary' to sync from 'primary' using the "forceSyncSourceCandidate" failpoint to
+    // ensure that an intermittent connectivity issue doesn't lead to the secondary not advancing
+    // its belief of the majority commit point. This avoids any complications that would arise due
+    // to SERVER-33248.
+    assert.commandWorked(secondary.adminCommand({
+        configureFailPoint: "forceSyncSourceCandidate",
+        mode: "alwaysOn",
+        data: {hostAndPort: primary.host}
+    }));
+    rst.awaitSyncSource(secondary, primary);
+
     // We also prevent all nodes in the replica set from advancing oldest_timestamp. This ensures
     // that the snapshot associated with 'clusterTime' is retained for the duration of this test.
     rst.nodes.forEach(conn => {
diff --git a/jstests/replsets/libs/secondary_reads_test.js b/jstests/replsets/libs/secondary_reads_test.js
index da22f9b73b5..2ca1117b6ed 100644
--- a/jstests/replsets/libs/secondary_reads_test.js
+++ b/jstests/replsets/libs/secondary_reads_test.js
@@ -24,7 +24,9 @@ function SecondaryReadsTest(name = "secondary_reads_test") {
      * two-node replica set running with the latest version.
      */
     function performStandardSetup() {
-        let replSet = new ReplSetTest({name, nodes: 2});
+        // TODO: Periodic noop writes can be removed once SERVER-33248 is complete.
+        let replSet = new ReplSetTest(
+            {name, nodes: 2, nodeOptions: {setParameter: {writePeriodicNoops: true}}});
         replSet.startSet();
 
         const nodes = replSet.nodeList();
diff --git a/src/mongo/db/repl/member_data.cpp b/src/mongo/db/repl/member_data.cpp
index 83890cc2a51..50e2725ca81 100644
--- a/src/mongo/db/repl/member_data.cpp
+++ b/src/mongo/db/repl/member_data.cpp
@@ -47,9 +47,7 @@ MemberData::MemberData() : _health(-1), _authIssue(false), _configIndex(-1), _is
     _lastResponse.setAppliedOpTime(OpTime());
 }
 
-bool MemberData::setUpValues(Date_t now,
-                             ReplSetHeartbeatResponse&& hbResponse,
-                             OpTime lastOpCommitted) {
+bool MemberData::setUpValues(Date_t now, ReplSetHeartbeatResponse&& hbResponse) {
     _health = 1;
     if (_upSince == Date_t()) {
         _upSince = now;
@@ -60,10 +58,6 @@ bool MemberData::setUpValues(Date_t now,
     _lastUpdateStale = false;
     _updatedSinceRestart = true;
 
-    if (!lastOpCommitted.isNull()) {
-        _lastOpCommitted = lastOpCommitted;
-    }
-
     if (!hbResponse.hasState()) {
         hbResponse.setState(MemberState::RS_UNKNOWN);
     }
diff --git a/src/mongo/db/repl/member_data.h b/src/mongo/db/repl/member_data.h
index ab4352704bb..5e1af9ac22e 100644
--- a/src/mongo/db/repl/member_data.h
+++ b/src/mongo/db/repl/member_data.h
@@ -76,9 +76,6 @@ public:
     OpTime getHeartbeatDurableOpTime() const {
         return _lastResponse.hasDurableOpTime() ? _lastResponse.getDurableOpTime() : OpTime();
     }
-    OpTime getHeartbeatLastOpCommitted() const {
-        return _lastOpCommitted;
-    }
     int getConfigVersion() const {
         return _lastResponse.getConfigVersion();
     }
@@ -146,10 +143,9 @@ public:
 
     /**
      * Sets values in this object from the results of a successful heartbeat command.
-     * 'lastOpCommitted' should be extracted from the heartbeat metadata.
      * Returns whether or not the optimes advanced as a result of this heartbeat response.
      */
-    bool setUpValues(Date_t now, ReplSetHeartbeatResponse&& hbResponse, OpTime lastOpCommitted);
+    bool setUpValues(Date_t now, ReplSetHeartbeatResponse&& hbResponse);
 
     /**
      * Sets values in this object from the results of a erroring/failed heartbeat command.
@@ -265,11 +261,6 @@ private:
     // Last known OpTime that the replica has applied, whether journaled or unjournaled.
     OpTime _lastAppliedOpTime;
 
-    // OpTime of the most recently committed op of which the node was aware, extracted from the
-    // heartbeat metadata. Note that only arbiters should update their knowledge of the commit point
-    // from heartbeat data.
-    OpTime _lastOpCommitted;
-
     // TODO(russotto): Since memberData is kept in config order, _configIndex
     // and _isSelf may not be necessary.
     // Index of this member in the replica set configuration.
diff --git a/src/mongo/db/repl/oplog_fetcher.cpp b/src/mongo/db/repl/oplog_fetcher.cpp
index 73808edf3b8..ce499fd0c89 100644
--- a/src/mongo/db/repl/oplog_fetcher.cpp
+++ b/src/mongo/db/repl/oplog_fetcher.cpp
@@ -119,11 +119,8 @@ BSONObj makeMetadataObject(bool isV1ElectionProtocol) {
  * Checks the first batch of results from query.
  * 'documents' are the first batch of results returned from tailing the remote oplog.
  * 'lastFetched' optime and hash should be consistent with the predicate in the query.
- * 'lastOpCommitted' is the OpTime of the most recently committed op of which this node is aware.
  * 'remoteLastOpApplied' is the last OpTime applied on the sync source. This is optional for
  * compatibility with 3.4 servers that do not send OplogQueryMetadata.
- * 'remoteLastOpCommitted' is the OpTime of the most recently committed op of which the sync source
- * is aware.
  * 'requiredRBID' is a RollbackID received when we chose the sync source that we use here to
  * guarantee we have not rolled back since we confirmed the sync source had our minValid.
  * 'remoteRBID' is a RollbackId for the sync source returned in this oplog query. This is optional
@@ -132,17 +129,14 @@ BSONObj makeMetadataObject(bool isV1ElectionProtocol) {
  * oplog to be ahead of ours. If false, the sync source's oplog is allowed to be at the same point
  * as ours, but still cannot be behind ours.
  *
- * TODO (SERVER-27668): Make remoteLastOpApplied, remoteLastOpCommitted, and remoteRBID
- * non-optional.
+ * TODO (SERVER-27668): Make remoteLastOpApplied and remoteRBID non-optional in mongodb 3.8.
  *
  * Returns OplogStartMissing if we cannot find the optime of the last fetched operation in
  * the remote oplog.
  */
 Status checkRemoteOplogStart(const Fetcher::Documents& documents,
                              OpTimeWithHash lastFetched,
-                             OpTime lastOpCommitted,
                              boost::optional<OpTime> remoteLastOpApplied,
-                             boost::optional<OpTime> remoteLastOpCommitted,
                              int requiredRBID,
                              boost::optional<int> remoteRBID,
                              bool requireFresherSyncSource) {
@@ -166,49 +160,34 @@ Status checkRemoteOplogStart(const Fetcher::Documents& documents,
         }
     }
 
-    // The sync source could be behind us if it rolled back after we selected it. We could have
-    // failed to detect the rollback if it occurred between sync source selection (when we check the
-    // candidate is ahead of us) and sync source resolution (when we got 'requiredRBID'). If the
-    // sync source is now behind us, choose a new sync source to prevent going into rollback.
-    if (remoteLastOpApplied && (*remoteLastOpApplied < lastFetched.opTime)) {
+    // The SyncSourceResolver never checks that the sync source candidate is actually ahead of
+    // us. Rather than have it check there with an extra network roundtrip, we check here.
+    if (requireFresherSyncSource && remoteLastOpApplied &&
+        (*remoteLastOpApplied <= lastFetched.opTime)) {
         return Status(ErrorCodes::InvalidSyncSource,
                       str::stream() << "Sync source's last applied OpTime "
                                     << remoteLastOpApplied->toString()
-                                    << " is older than our last fetched OpTime "
+                                    << " is not greater than our last fetched OpTime "
                                     << lastFetched.opTime.toString()
                                     << ". Choosing new sync source.");
-    }
-
-    // If 'requireFresherSyncSource' is true, we must check that the sync source's
-    // lastApplied/lastOpCommitted is ahead of us to prevent forming a cycle. Although we check for
-    // this condition in sync source selection, if an undetected rollback occurred between sync
-    // source selection and sync source resolution, this condition may no longer hold.
-    // 'requireFresherSyncSource' is false for initial sync, since no other node can sync off an
-    // initial syncing node, so we do not need to check for cycles. In addition, it would be
-    // problematic to check this condition for initial sync, since the 'lastFetched' OpTime will
-    // almost always equal the 'remoteLastApplied', since we fetch the sync source's last applied
-    // OpTime to determine where to start our OplogFetcher.
-    if (requireFresherSyncSource && remoteLastOpApplied && remoteLastOpCommitted &&
-        std::tie(*remoteLastOpApplied, *remoteLastOpCommitted) <=
-            std::tie(lastFetched.opTime, lastOpCommitted)) {
+    } else if (remoteLastOpApplied && (*remoteLastOpApplied < lastFetched.opTime)) {
+        // In initial sync, the lastFetched OpTime will almost always equal the remoteLastOpApplied
+        // since we fetch the sync source's last applied OpTime to determine where to start our
+        // OplogFetcher. This is fine since no other node can sync off of an initial syncing node
+        // and thus cannot form a sync source cycle. To account for this, we must relax the
+        // constraint on our sync source being fresher.
         return Status(ErrorCodes::InvalidSyncSource,
-                      str::stream()
-                          << "Sync source cannot be behind me, and if I am up-to-date with the "
-                             "sync source, it must have a higher lastOpCommitted. "
-                          << "My last fetched oplog optime: "
-                          << lastFetched.opTime.toString()
-                          << ", latest oplog optime of sync source: "
-                          << remoteLastOpApplied->toString()
-                          << ", my lastOpCommitted: "
-                          << lastOpCommitted.toString()
-                          << ", lastOpCommitted of sync source: "
-                          << remoteLastOpCommitted->toString());
+                      str::stream() << "Sync source's last applied OpTime "
+                                    << remoteLastOpApplied->toString()
+                                    << " is older than our last fetched OpTime "
+                                    << lastFetched.opTime.toString()
+                                    << ". Choosing new sync source.");
     }
 
-    // At this point we know that our sync source has our minValid and is not behind us, so if our
+    // At this point we know that our sync source has our minValid and is ahead of us, so if our
     // history diverges from our sync source's we should prefer its history and roll back ours.
 
-    // Since we checked for rollback and our sync source is not behind us, an empty batch means that
+    // Since we checked for rollback and our sync source is ahead of us, an empty batch means that
     // we have a higher timestamp on our last fetched OpTime than our sync source's last applied
     // OpTime, but a lower term. When this occurs, we must roll back our inconsistent oplog entry.
     if (documents.empty()) {
@@ -450,17 +429,12 @@ StatusWith<BSONObj> OplogFetcher::_onSuccessfulBatch(const Fetcher::QueryRespons
         auto remoteRBID = oqMetadata ? boost::make_optional(oqMetadata->getRBID()) : boost::none;
         auto remoteLastApplied =
             oqMetadata ? boost::make_optional(oqMetadata->getLastOpApplied()) : boost::none;
-        auto remoteLastOpCommitted =
-            oqMetadata ? boost::make_optional(oqMetadata->getLastOpCommitted()) : boost::none;
-        auto status = checkRemoteOplogStart(
-            documents,
-            lastFetched,
-            _dataReplicatorExternalState->getCurrentTermAndLastCommittedOpTime().opTime,
-            remoteLastApplied,
-            remoteLastOpCommitted,
-            _requiredRBID,
-            remoteRBID,
-            _requireFresherSyncSource);
+        auto status = checkRemoteOplogStart(documents,
+                                            lastFetched,
+                                            remoteLastApplied,
+                                            _requiredRBID,
+                                            remoteRBID,
+                                            _requireFresherSyncSource);
         if (!status.isOK()) {
             // Stop oplog fetcher and execute rollback if necessary.
             return status;
diff --git a/src/mongo/db/repl/oplog_fetcher_test.cpp b/src/mongo/db/repl/oplog_fetcher_test.cpp
index b4d9a5ccbae..ce93a2b0e4a 100644
--- a/src/mongo/db/repl/oplog_fetcher_test.cpp
+++ b/src/mongo/db/repl/oplog_fetcher_test.cpp
@@ -361,22 +361,6 @@ TEST_F(OplogFetcherTest, MetadataAndBatchAreNotProcessedWhenSyncSourceIsNotAhead
 }
 
 TEST_F(OplogFetcherTest,
-       MetadataAndBatchAreProcessedWhenSyncSourceIsNotAheadButHasHigherLastOpCommitted) {
-    rpc::ReplSetMetadata replMetadata(1, OpTime(), OpTime(), 1, OID::gen(), -1, -1);
-    rpc::OplogQueryMetadata oqMetadata(remoteNewerOpTime, lastFetched.opTime, rbid, 2, 2);
-    BSONObjBuilder bob;
-    ASSERT_OK(replMetadata.writeToMetadata(&bob));
-    ASSERT_OK(oqMetadata.writeToMetadata(&bob));
-    auto metadataObj = bob.obj();
-
-    auto entry = makeNoopOplogEntry(lastFetched);
-    auto shutdownState =
-        processSingleBatch({makeCursorResponse(0, {entry}), metadataObj, Milliseconds(0)}, false);
-    ASSERT_OK(shutdownState->getStatus());
-    ASSERT(dataReplicatorExternalState->metadataWasProcessed);
-}
-
-TEST_F(OplogFetcherTest,
        MetadataAndBatchAreNotProcessedWhenSyncSourceIsBehindWithoutRequiringFresherSyncSource) {
     rpc::ReplSetMetadata replMetadata(1, OpTime(), OpTime(), 1, OID::gen(), -1, -1);
     rpc::OplogQueryMetadata oqMetadata(staleOpTime, staleOpTime, rbid, 2, 2);
diff --git a/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp b/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
index 5e63283a129..01af85ca544 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_heartbeat.cpp
@@ -154,7 +154,6 @@ void ReplicationCoordinatorImpl::_handleHeartbeatResponse(
     }
 
     ReplSetHeartbeatResponse hbResponse;
-    OpTime lastOpCommitted;
     BSONObj resp;
     if (responseStatus.isOK()) {
         resp = cbData.response.data;
@@ -183,11 +182,9 @@ void ReplicationCoordinatorImpl::_handleHeartbeatResponse(
             replMetadata = responseStatus;
         }
         if (replMetadata.isOK()) {
-            lastOpCommitted = replMetadata.getValue().getLastOpCommitted();
-
             // Arbiters are the only nodes allowed to advance their commit point via heartbeats.
             if (_getMemberState_inlock().arbiter()) {
-                _advanceCommitPoint_inlock(lastOpCommitted);
+                _advanceCommitPoint_inlock(replMetadata.getValue().getLastOpCommitted());
             }
             // Asynchronous stepdown could happen, but it will wait for _mutex and execute
             // after this function, so we cannot and don't need to wait for it to finish.
@@ -216,8 +213,8 @@ void ReplicationCoordinatorImpl::_handleHeartbeatResponse(
         hbStatusResponse = StatusWith<ReplSetHeartbeatResponse>(responseStatus);
     }
 
-    HeartbeatResponseAction action = _topCoord->processHeartbeatResponse(
-        now, networkTime, target, hbStatusResponse, lastOpCommitted);
+    HeartbeatResponseAction action =
+        _topCoord->processHeartbeatResponse(now, networkTime, target, hbStatusResponse);
 
     if (action.getAction() == HeartbeatResponseAction::NoAction && hbStatusResponse.isOK() &&
         hbStatusResponse.getValue().hasState() &&
diff --git a/src/mongo/db/repl/topology_coordinator.cpp b/src/mongo/db/repl/topology_coordinator.cpp
index 9fbf9dcfa51..1d1d242ed14 100644
--- a/src/mongo/db/repl/topology_coordinator.cpp
+++ b/src/mongo/db/repl/topology_coordinator.cpp
@@ -387,21 +387,13 @@ HostAndPort TopologyCoordinator::chooseNewSyncSource(Date_t now,
                     continue;
                 }
             }
-            // Do not select a candidate that is behind me. If I am up to date with the candidate,
-            // only select them if they have a higher lastOpCommitted.
-            if (std::tuple<OpTime, OpTime>(it->getHeartbeatAppliedOpTime(),
-                                           it->getHeartbeatLastOpCommitted()) <=
-                std::tie(lastOpTimeFetched, _lastCommittedOpTime)) {
-                LOG(1) << "Cannot select this sync source. Sync source cannot be behind me, and if "
-                          "I am up-to-date with the sync source, it must have a higher "
-                          "lastOpCommitted. "
-                       << "Sync candidate: " << itMemberConfig.getHostAndPort()
-                       << ", my last fetched oplog optime: " << lastOpTimeFetched.toBSON()
-                       << ", latest oplog optime of sync candidate: "
-                       << it->getHeartbeatAppliedOpTime().toBSON()
-                       << ", my lastOpCommitted: " << _lastCommittedOpTime
-                       << ", lastOpCommitted of sync candidate: "
-                       << it->getHeartbeatLastOpCommitted();
+            // only consider candidates that are ahead of where we are
+            if (it->getHeartbeatAppliedOpTime() <= lastOpTimeFetched) {
+                LOG(1) << "Cannot select sync source equal to or behind our last fetched optime. "
+                       << "My last fetched oplog optime: " << lastOpTimeFetched.toBSON()
+                       << ", latest oplog optime of sync candidate "
+                       << itMemberConfig.getHostAndPort() << ": "
+                       << it->getHeartbeatAppliedOpTime().toBSON();
                 continue;
             }
             // Candidate cannot be more latent than anything we've already considered.
@@ -1035,8 +1027,7 @@ HeartbeatResponseAction TopologyCoordinator::processHeartbeatResponse(
     Date_t now,
     Milliseconds networkRoundTripTime,
     const HostAndPort& target,
-    const StatusWith<ReplSetHeartbeatResponse>& hbResponse,
-    OpTime lastOpCommitted) {
+    const StatusWith<ReplSetHeartbeatResponse>& hbResponse) {
     const MemberState originalState = getMemberState();
     PingStats& hbStats = _pings[target];
     invariant(hbStats.getLastHeartbeatStartDate() != Date_t());
@@ -1157,7 +1148,7 @@ HeartbeatResponseAction TopologyCoordinator::processHeartbeatResponse(
         ReplSetHeartbeatResponse hbr = std::move(hbResponse.getValue());
         LOG(3) << "setUpValues: heartbeat response good for member _id:" << member.getId()
                << ", msg:  " << hbr.getHbMsg();
-        advancedOpTime = hbData.setUpValues(now, std::move(hbr), lastOpCommitted);
+        advancedOpTime = hbData.setUpValues(now, std::move(hbr));
     }
 
     HeartbeatResponseAction nextAction;
@@ -1995,8 +1986,7 @@ void TopologyCoordinator::setCurrentPrimary_forTest(int primaryIndex,
             hbResponse.setHbMsg("");
             _memberData.at(primaryIndex)
                 .setUpValues(_memberData.at(primaryIndex).getLastHeartbeat(),
-                             std::move(hbResponse),
-                             _memberData.at(primaryIndex).getHeartbeatLastOpCommitted());
+                             std::move(hbResponse));
         }
         _currentPrimaryIndex = primaryIndex;
     }
@@ -2263,10 +2253,6 @@ void TopologyCoordinator::fillMemberData(BSONObjBuilder* result) {
                 entry.append("optime", lastDurableOpTime.getTimestamp());
             }
             entry.append("host", memberData.getHostAndPort().toString());
-
-            const auto lastOpCommitted = memberData.getHeartbeatLastOpCommitted();
-            entry.append("heartbeatLastOpCommitted", lastOpCommitted.toBSON());
-
             if (_selfIndex >= 0) {
                 const int memberId = memberData.getMemberId();
                 invariant(memberId >= 0);
@@ -3234,25 +3220,18 @@ bool TopologyCoordinator::shouldChangeSyncSource(
     // If OplogQueryMetadata was provided, use its values, otherwise use the ones in
     // ReplSetMetadata.
     OpTime currentSourceOpTime;
-    OpTime currentSourceLastOpCommitted;
     int syncSourceIndex = -1;
     int primaryIndex = -1;
     if (oqMetadata) {
         currentSourceOpTime =
             std::max(oqMetadata->getLastOpApplied(),
                      _memberData.at(currentSourceIndex).getHeartbeatAppliedOpTime());
-        currentSourceLastOpCommitted =
-            std::max(oqMetadata->getLastOpCommitted(),
-                     _memberData.at(currentSourceIndex).getHeartbeatLastOpCommitted());
         syncSourceIndex = oqMetadata->getSyncSourceIndex();
         primaryIndex = oqMetadata->getPrimaryIndex();
     } else {
         currentSourceOpTime =
             std::max(replMetadata.getLastOpVisible(),
                      _memberData.at(currentSourceIndex).getHeartbeatAppliedOpTime());
-        currentSourceLastOpCommitted =
-            std::max(replMetadata.getLastOpCommitted(),
-                     _memberData.at(currentSourceIndex).getHeartbeatLastOpCommitted());
         syncSourceIndex = replMetadata.getSyncSourceIndex();
         primaryIndex = replMetadata.getPrimaryIndex();
     }
@@ -3267,20 +3246,12 @@ bool TopologyCoordinator::shouldChangeSyncSource(
     // unless they are primary.
     const OpTime myLastOpTime = getMyLastAppliedOpTime();
     if (_rsConfig.getProtocolVersion() == 1 && syncSourceIndex == -1 &&
-        std::tie(currentSourceOpTime, currentSourceLastOpCommitted) <=
-            std::tie(myLastOpTime, _lastCommittedOpTime) &&
-        primaryIndex != currentSourceIndex) {
+        currentSourceOpTime <= myLastOpTime && primaryIndex != currentSourceIndex) {
         std::stringstream logMessage;
-
-        logMessage << "Choosing new sync source. Our current sync source is not primary and does "
-                      "not have a sync source, so we require that it is not behind us, and that if "
-                      "we are up-to-date with it, it has a higher lastOpCommitted. "
-                   << "Current sync source: " << currentSource.toString()
-                   << ", my last fetched oplog optime: " << myLastOpTime
-                   << ", latest oplog optime of sync source: " << currentSourceOpTime
-                   << ", my lastOpCommitted: " << _lastCommittedOpTime
-                   << ", lastOpCommitted of sync source: " << currentSourceLastOpCommitted;
-
+        logMessage << "Choosing new sync source because our current sync source, "
+                   << currentSource.toString() << ", has an OpTime (" << currentSourceOpTime
+                   << ") which is not ahead of ours (" << myLastOpTime
+                   << "), it does not have a sync source, and it's not the primary";
         if (primaryIndex >= 0) {
             logMessage << " (" << _rsConfig.getMemberAt(primaryIndex).getHostAndPort() << " is)";
         } else {
diff --git a/src/mongo/db/repl/topology_coordinator.h b/src/mongo/db/repl/topology_coordinator.h
index 55cc38292f6..feb1c351c43 100644
--- a/src/mongo/db/repl/topology_coordinator.h
+++ b/src/mongo/db/repl/topology_coordinator.h
@@ -392,8 +392,8 @@ public:
         Date_t now, const std::string& ourSetName, const HostAndPort& target);
 
     /**
-     * Processes a heartbeat response from "target" that arrived around "now" with "lastOpCommitted"
-     * in the metadata, having spent "networkRoundTripTime" millis on the network.
+     * Processes a heartbeat response from "target" that arrived around "now", having
+     * spent "networkRoundTripTime" millis on the network.
      *
      * Updates internal topology coordinator state, and returns instructions about what action
      * to take next.
@@ -422,8 +422,7 @@ public:
         Date_t now,
         Milliseconds networkRoundTripTime,
         const HostAndPort& target,
-        const StatusWith<ReplSetHeartbeatResponse>& hbResponse,
-        OpTime lastOpCommitted);
+        const StatusWith<ReplSetHeartbeatResponse>& hbResponse);
 
     /**
      *  Returns whether or not at least 'numNodes' have reached the given opTime.
diff --git a/src/mongo/db/repl/topology_coordinator_v1_test.cpp b/src/mongo/db/repl/topology_coordinator_v1_test.cpp
index e60d324dd5d..a45f54805da 100644
--- a/src/mongo/db/repl/topology_coordinator_v1_test.cpp
+++ b/src/mongo/db/repl/topology_coordinator_v1_test.cpp
@@ -172,10 +172,9 @@ protected:
     // Only set visibleOpTime, primaryIndex and syncSourceIndex
     ReplSetMetadata makeReplSetMetadata(OpTime visibleOpTime = OpTime(),
                                         int primaryIndex = -1,
-                                        int syncSourceIndex = -1,
-                                        OpTime committedOpTime = OpTime()) {
+                                        int syncSourceIndex = -1) {
         return ReplSetMetadata(_topo->getTerm(),
-                               committedOpTime,
+                               OpTime(),
                                visibleOpTime,
                                _currentConfig.getConfigVersion(),
                                OID(),
@@ -187,10 +186,8 @@ protected:
     // Only set lastAppliedOpTime, primaryIndex and syncSourceIndex
     OplogQueryMetadata makeOplogQueryMetadata(OpTime lastAppliedOpTime = OpTime(),
                                               int primaryIndex = -1,
-                                              int syncSourceIndex = -1,
-                                              OpTime committedOpTime = OpTime()) {
-        return OplogQueryMetadata(
-            committedOpTime, lastAppliedOpTime, -1, primaryIndex, syncSourceIndex);
+                                              int syncSourceIndex = -1) {
+        return OplogQueryMetadata(OpTime(), lastAppliedOpTime, -1, primaryIndex, syncSourceIndex);
     }
 
     HeartbeatResponseAction receiveUpHeartbeat(const HostAndPort& member,
@@ -198,15 +195,13 @@ protected:
                                                MemberState memberState,
                                                const OpTime& electionTime,
                                                const OpTime& lastOpTimeSender,
-                                               const HostAndPort& syncingTo = HostAndPort(),
-                                               const OpTime& lastOpCommittedSender = OpTime()) {
+                                               const HostAndPort& syncingTo = HostAndPort()) {
         return _receiveHeartbeatHelper(Status::OK(),
                                        member,
                                        setName,
                                        memberState,
                                        electionTime.getTimestamp(),
                                        lastOpTimeSender,
-                                       lastOpCommittedSender,
                                        Milliseconds(1),
                                        syncingTo);
     }
@@ -224,7 +219,6 @@ protected:
                                        MemberState::RS_UNKNOWN,
                                        Timestamp(),
                                        OpTime(),
-                                       OpTime(),
                                        roundTripTime,
                                        HostAndPort());
     }
@@ -233,15 +227,13 @@ protected:
                                                 const std::string& setName,
                                                 MemberState memberState,
                                                 const OpTime& lastOpTimeSender,
-                                                Milliseconds roundTripTime = Milliseconds(1),
-                                                const OpTime& lastOpCommittedSender = OpTime()) {
+                                                Milliseconds roundTripTime = Milliseconds(1)) {
         return _receiveHeartbeatHelper(Status::OK(),
                                        member,
                                        setName,
                                        memberState,
                                        Timestamp(),
                                        lastOpTimeSender,
-                                       lastOpCommittedSender,
                                        roundTripTime,
                                        HostAndPort());
     }
@@ -253,7 +245,6 @@ private:
                                                     MemberState memberState,
                                                     Timestamp electionTime,
                                                     const OpTime& lastOpTimeSender,
-                                                    const OpTime& lastOpCommittedSender,
                                                     Milliseconds roundTripTime,
                                                     const HostAndPort& syncingTo) {
         ReplSetHeartbeatResponse hb;
@@ -271,8 +262,7 @@ private:
 
         getTopoCoord().prepareHeartbeatRequestV1(now(), setName, member);
         now() += roundTripTime;
-        return getTopoCoord().processHeartbeatResponse(
-            now(), roundTripTime, member, hbResponse, lastOpCommittedSender);
+        return getTopoCoord().processHeartbeatResponse(now(), roundTripTime, member, hbResponse);
     }
 
 private:
@@ -587,80 +577,6 @@ TEST_F(TopoCoordTest, NodeWontChooseSyncSourceFromOlderTerm) {
     ASSERT(getTopoCoord().getSyncSourceAddress().empty());
 }
 
-TEST_F(TopoCoordTest, NodeCanChooseSyncSourceWithSameLastAppliedAndHigherLastOpCommitted) {
-    updateConfig(BSON("_id"
-                      << "rs0"
-                      << "version"
-                      << 1
-                      << "members"
-                      << BSON_ARRAY(BSON("_id" << 1 << "host"
-                                               << "hself")
-                                    << BSON("_id" << 10 << "host"
-                                                  << "h1"))),
-                 0);
-
-    setSelfMemberState(MemberState::RS_SECONDARY);
-    OpTime lastApplied = OpTime(Timestamp(100, 3), 3);
-    OpTime ourLastOpCommitted = OpTime(Timestamp(100, 1), 3);
-    OpTime lastOpCommittedSyncSource = OpTime(Timestamp(100, 2), 3);
-
-    heartbeatFromMember(HostAndPort("h1"),
-                        "rs0",
-                        MemberState::RS_SECONDARY,
-                        lastApplied,
-                        Milliseconds(100),
-                        lastOpCommittedSyncSource);
-
-    // Record 2nd round of pings to allow choosing a new sync source.
-    heartbeatFromMember(HostAndPort("h1"),
-                        "rs0",
-                        MemberState::RS_SECONDARY,
-                        lastApplied,
-                        Milliseconds(100),
-                        lastOpCommittedSyncSource);
-
-    ASSERT(getTopoCoord().advanceLastCommittedOpTime(ourLastOpCommitted));
-    getTopoCoord().chooseNewSyncSource(
-        now()++, lastApplied, TopologyCoordinator::ChainingPreference::kUseConfiguration);
-    ASSERT_EQUALS(HostAndPort("h1"), getTopoCoord().getSyncSourceAddress());
-}
-
-TEST_F(TopoCoordTest, NodeCannotChooseSyncSourceWithSameLastAppliedAndSameLastOpCommitted) {
-    updateConfig(BSON("_id"
-                      << "rs0"
-                      << "version"
-                      << 1
-                      << "members"
-                      << BSON_ARRAY(BSON("_id" << 1 << "host"
-                                               << "hself")
-                                    << BSON("_id" << 10 << "host"
-                                                  << "h1"))),
-                 0);
-
-    setSelfMemberState(MemberState::RS_SECONDARY);
-    OpTime lastApplied = OpTime(Timestamp(100, 3), 3);
-    OpTime lastOpCommitted = OpTime(Timestamp(100, 1), 3);
-
-    heartbeatFromMember(HostAndPort("h1"),
-                        "rs0",
-                        MemberState::RS_SECONDARY,
-                        lastApplied,
-                        Milliseconds(100),
-                        lastOpCommitted);
-
-    // Record 2nd round of pings to allow choosing a new sync source.
-    heartbeatFromMember(HostAndPort("h1"),
-                        "rs0",
-                        MemberState::RS_SECONDARY,
-                        lastApplied,
-                        Milliseconds(100),
-                        lastOpCommitted);
-
-    ASSERT(getTopoCoord().advanceLastCommittedOpTime(lastOpCommitted));
-    getTopoCoord().chooseNewSyncSource(
-        now()++, lastApplied, TopologyCoordinator::ChainingPreference::kUseConfiguration);
-    ASSERT(getTopoCoord().getSyncSourceAddress().empty());
-}
 
 TEST_F(TopoCoordTest, ChooseOnlyPrimaryAsSyncSourceWhenChainingIsDisallowed) {
     updateConfig(BSON("_id"
@@ -1700,7 +1616,7 @@ TEST_F(TopoCoordTest, ReplSetGetStatus) {
     HostAndPort member = HostAndPort("test0:1234");
     getTopoCoord().prepareHeartbeatRequestV1(startupTime + Milliseconds(1), setName, member);
     getTopoCoord().processHeartbeatResponse(
-        startupTime + Milliseconds(2), Milliseconds(1), member, hbResponseGood, OpTime());
+        startupTime + Milliseconds(2), Milliseconds(1), member, hbResponseGood);
     getTopoCoord().prepareHeartbeatRequestV1(startupTime + Milliseconds(3), setName, member);
     Date_t timeoutTime =
         startupTime + Milliseconds(3) + ReplSetConfig::kDefaultHeartbeatTimeoutPeriod;
@@ -1709,12 +1625,12 @@ TEST_F(TopoCoordTest, ReplSetGetStatus) {
         StatusWith<ReplSetHeartbeatResponse>(Status(ErrorCodes::HostUnreachable, ""));
 
     getTopoCoord().processHeartbeatResponse(
-        timeoutTime, Milliseconds(5000), member, hbResponseDown, OpTime());
+        timeoutTime, Milliseconds(5000), member, hbResponseDown);
 
     member = HostAndPort("test1:1234");
     getTopoCoord().prepareHeartbeatRequestV1(startupTime + Milliseconds(2), setName, member);
     getTopoCoord().processHeartbeatResponse(
-        heartbeatTime, Milliseconds(4000), member, hbResponseGood, OpTime());
+        heartbeatTime, Milliseconds(4000), member, hbResponseGood);
     makeSelfPrimary(electionTime);
     getTopoCoord().setMyLastAppliedOpTime(oplogProgress, startupTime, false);
     getTopoCoord().setMyLastDurableOpTime(oplogDurable, startupTime, false);
@@ -1894,7 +1810,7 @@ TEST_F(TopoCoordTest, HeartbeatFrequencyShouldBeHalfElectionTimeoutWhenArbiter)
     std::pair<ReplSetHeartbeatArgsV1, Milliseconds> uppingRequest =
         getTopoCoord().prepareHeartbeatRequestV1(requestDate, "myset", target);
     auto action = getTopoCoord().processHeartbeatResponse(
-        requestDate, Milliseconds(0), target, makeStatusWith<ReplSetHeartbeatResponse>(), OpTime());
+        requestDate, Milliseconds(0), target, makeStatusWith<ReplSetHeartbeatResponse>());
     Date_t expected(now() + Milliseconds(2500));
     ASSERT_EQUALS(expected, action.getNextHeartbeatStartDate());
 }
@@ -3554,31 +3470,6 @@ TEST_F(HeartbeatResponseTestV1,
                                               now()));
     ASSERT_FALSE(getTopoCoord().shouldChangeSyncSource(
         HostAndPort("host2"), makeReplSetMetadata(newerThanLastOpTimeApplied), boost::none, now()));
-
-    // If we are as up-to-date as this sync source, but it has a higher lastOpCommitted, we will not
-    // change sync sources.
-    OpTime lastOpCommitted = OpTime(Timestamp(100, 0), 0);
-    OpTime newerLastOpCommitted = OpTime(Timestamp(200, 0), 0);
-    ASSERT(getTopoCoord().advanceLastCommittedOpTime(lastOpCommitted));
-    nextAction = receiveUpHeartbeat(HostAndPort("host2"),
-                                    "rs0",
-                                    MemberState::RS_SECONDARY,
-                                    election,
-                                    lastOpTimeApplied,
-                                    HostAndPort(),
-                                    newerLastOpCommitted);
-    ASSERT_NO_ACTION(nextAction.getAction());
-    ASSERT_FALSE(getTopoCoord().shouldChangeSyncSource(
-        HostAndPort("host2"),
-        makeReplSetMetadata(),
-        makeOplogQueryMetadata(lastOpTimeApplied, -1, -1, newerLastOpCommitted),
-        now()));
-
-    ASSERT_FALSE(getTopoCoord().shouldChangeSyncSource(
-        HostAndPort("host2"),
-        makeReplSetMetadata(lastOpTimeApplied, -1, -1, newerLastOpCommitted),
-        boost::none,
-        now()));
 }
 
 TEST_F(HeartbeatResponseTestV1, ShouldNotChangeSyncSourceWhenFresherMemberIsDown) {
@@ -3835,7 +3726,7 @@ TEST_F(HeartbeatResponseTestV1, ReconfigNodeRemovedBetweenHeartbeatRequestAndRep
     hb.setElectionTime(election.getTimestamp());
     StatusWith<ReplSetHeartbeatResponse> hbResponse = StatusWith<ReplSetHeartbeatResponse>(hb);
     HeartbeatResponseAction action = getTopoCoord().processHeartbeatResponse(
-        now()++, Milliseconds(0), HostAndPort("host3"), hbResponse, OpTime());
+        now()++, Milliseconds(0), HostAndPort("host3"), hbResponse);
 
     // primary should not be set and we should perform NoAction in response
     ASSERT_EQUALS(-1, getCurrentPrimaryIndex());
@@ -3883,7 +3774,7 @@ TEST_F(HeartbeatResponseTestV1, ReconfigBetweenHeartbeatRequestAndRepsonse) {
     StatusWith<ReplSetHeartbeatResponse> hbResponse = StatusWith<ReplSetHeartbeatResponse>(hb);
     getTopoCoord().setMyLastAppliedOpTime(lastOpTimeApplied, Date_t(), false);
     HeartbeatResponseAction action = getTopoCoord().processHeartbeatResponse(
-        now()++, Milliseconds(0), HostAndPort("host3"), hbResponse, OpTime());
+        now()++, Milliseconds(0), HostAndPort("host3"), hbResponse);
 
     // now primary should be host3, index 1, and we should perform NoAction in response
     ASSERT_EQUALS(1, getCurrentPrimaryIndex());
@@ -4059,15 +3950,13 @@ TEST_F(TopoCoordTest, FreshestNodeDoesCatchupTakeover) {
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host3:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     hbResp.setAppliedOpTime(behindOptime);
     hbResp.setState(MemberState::RS_PRIMARY);
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host2:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     getTopoCoord().updateTerm(1, Date_t());
 
     ASSERT_OK(getTopoCoord().becomeCandidateIfElectable(
@@ -4114,15 +4003,13 @@ TEST_F(TopoCoordTest, StaleNodeDoesntDoCatchupTakeover) {
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host3:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     hbResp.setAppliedOpTime(behindOptime);
     hbResp.setState(MemberState::RS_PRIMARY);
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host2:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     getTopoCoord().updateTerm(1, Date_t());
 
     Status result = getTopoCoord().becomeCandidateIfElectable(
@@ -4172,14 +4059,12 @@ TEST_F(TopoCoordTest, NodeDoesntDoCatchupTakeoverHeartbeatSaysPrimaryCaughtUp) {
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host3:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     hbResp.setState(MemberState::RS_PRIMARY);
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host2:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     getTopoCoord().updateTerm(1, Date_t());
 
     Status result = getTopoCoord().becomeCandidateIfElectable(
@@ -4232,15 +4117,13 @@ TEST_F(TopoCoordTest, NodeDoesntDoCatchupTakeoverIfTermNumbersSayPrimaryCaughtUp
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host3:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     hbResp.setAppliedOpTime(behindOptime);
     hbResp.setState(MemberState::RS_PRIMARY);
     getTopoCoord().processHeartbeatResponse(firstRequestDate + Milliseconds(1000),
                                             Milliseconds(999),
                                             HostAndPort("host2:27017"),
-                                            StatusWith<ReplSetHeartbeatResponse>(hbResp),
-                                            OpTime());
+                                            StatusWith<ReplSetHeartbeatResponse>(hbResp));
     getTopoCoord().updateTerm(1, Date_t());
 
     Status result = getTopoCoord().becomeCandidateIfElectable(
@@ -5805,8 +5688,7 @@ TEST_F(HeartbeatResponseTestV1, NodeDoesNotRetryHeartbeatIfTheFirstFailureTakesT
                                                 // no retry allowed.
         Milliseconds(4990),                     // Spent 4.99 of the 5 seconds in the network.
         target,
-        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::ExceededTimeLimit, "Took too long"),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::ExceededTimeLimit, "Took too long"));
 
     ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
     ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
@@ -5906,12 +5788,8 @@ public:
         Date_t _upRequestDate = unittest::assertGet(dateFromISOString("2014-08-29T12:55Z"));
         std::pair<ReplSetHeartbeatArgsV1, Milliseconds> uppingRequest =
             getTopoCoord().prepareHeartbeatRequestV1(_upRequestDate, "rs0", _target);
-        HeartbeatResponseAction upAction =
-            getTopoCoord().processHeartbeatResponse(_upRequestDate,
-                                                    Milliseconds(0),
-                                                    _target,
-                                                    makeStatusWith<ReplSetHeartbeatResponse>(),
-                                                    OpTime());
+        HeartbeatResponseAction upAction = getTopoCoord().processHeartbeatResponse(
+            _upRequestDate, Milliseconds(0), _target, makeStatusWith<ReplSetHeartbeatResponse>());
         ASSERT_EQUALS(HeartbeatResponseAction::NoAction, upAction.getAction());
         ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
 
@@ -5930,8 +5808,8 @@ public:
             _firstRequestDate + Seconds(4),  // 4 seconds elapsed, retry allowed.
             Milliseconds(3990),              // Spent 3.99 of the 4 seconds in the network.
             _target,
-            StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::ExceededTimeLimit, "Took too long"),
-            OpTime());  // We've never applied anything.
+            StatusWith<ReplSetHeartbeatResponse>(
+                ErrorCodes::ExceededTimeLimit, "Took too long"));  // We've never applied anything.
 
         ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
         ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
@@ -5988,8 +5866,8 @@ TEST_F(HeartbeatResponseTestOneRetryV1,
                                                   // no retry allowed.
         Milliseconds(1000),                       // Spent 1 of the 1.01 seconds in the network.
         target(),
-        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::ExceededTimeLimit, "Took too long"),
-        OpTime());  // We've never applied anything.
+        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::ExceededTimeLimit,
+                                             "Took too long"));  // We've never applied anything.
 
     ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
     ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
@@ -6009,8 +5887,7 @@ public:
                                                       // could retry.
             Milliseconds(400),  // Spent 0.4 of the 0.5 seconds in the network.
             target(),
-            StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::NodeNotFound, "Bad DNS?"),
-            OpTime());
+            StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::NodeNotFound, "Bad DNS?"));
         ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
         ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
         // Because the first retry failed without timing out, we expect to retry immediately.
@@ -6057,8 +5934,7 @@ TEST_F(HeartbeatResponseTestTwoRetriesV1, NodeDoesNotRetryHeartbeatsAfterFailing
                                                   // could still retry.
         Milliseconds(100),                        // Spent 0.1 of the 0.3 seconds in the network.
         target(),
-        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::NodeNotFound, "Bad DNS?"),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(ErrorCodes::NodeNotFound, "Bad DNS?"));
     ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
     ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
     // Because this is the second retry, rather than retry again, we expect to wait for a quarter
@@ -6099,8 +5975,7 @@ TEST_F(HeartbeatResponseTestTwoRetriesV1, HeartbeatThreeNonconsecutiveFailures)
         getTopoCoord().processHeartbeatResponse(firstRequestDate() + Milliseconds(4500),
                                                 Milliseconds(400),
                                                 target(),
-                                                StatusWith<ReplSetHeartbeatResponse>(response),
-                                                OpTime());
+                                                StatusWith<ReplSetHeartbeatResponse>(response));
 
     ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
     ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
@@ -6117,8 +5992,7 @@ TEST_F(HeartbeatResponseTestTwoRetriesV1, HeartbeatThreeNonconsecutiveFailures)
         firstRequestDate() + Milliseconds(7100),
         Milliseconds(400),
         target(),
-        StatusWith<ReplSetHeartbeatResponse>(Status{ErrorCodes::HostUnreachable, ""}),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(Status{ErrorCodes::HostUnreachable, ""}));
 
     ASSERT_EQUALS(HeartbeatResponseAction::NoAction, action.getAction());
     ASSERT_TRUE(TopologyCoordinator::Role::kFollower == getTopoCoord().getRole());
@@ -6174,8 +6048,7 @@ TEST_F(HeartbeatResponseHighVerbosityTestV1, UpdateHeartbeatDataOldConfig) {
         now()++,            // Time is left.
         Milliseconds(400),  // Spent 0.4 of the 0.5 second in the network.
         HostAndPort("host2"),
-        StatusWith<ReplSetHeartbeatResponse>(believesWeAreDownResponse),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(believesWeAreDownResponse));
     stopCapturingLogMessages();
     ASSERT_NO_ACTION(action.getAction());
     ASSERT_EQUALS(1, countLogLinesContaining("host2:27017 thinks that we are down"));
@@ -6224,8 +6097,7 @@ TEST_F(HeartbeatResponseHighVerbosityTestV1, UpdateHeartbeatDataSameConfig) {
         now()++,            // Time is left.
         Milliseconds(400),  // Spent 0.4 of the 0.5 second in the network.
         HostAndPort("host2"),
-        StatusWith<ReplSetHeartbeatResponse>(sameConfigResponse),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(sameConfigResponse));
     stopCapturingLogMessages();
     ASSERT_NO_ACTION(action.getAction());
     ASSERT_EQUALS(1,
@@ -6253,8 +6125,7 @@ TEST_F(HeartbeatResponseHighVerbosityTestV1,
         now()++,            // Time is left.
         Milliseconds(400),  // Spent 0.4 of the 0.5 second in the network.
         HostAndPort("host5"),
-        StatusWith<ReplSetHeartbeatResponse>(memberMissingResponse),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(memberMissingResponse));
     stopCapturingLogMessages();
     ASSERT_NO_ACTION(action.getAction());
     ASSERT_EQUALS(1, countLogLinesContaining("Could not find host5:27017 in current config"));
@@ -6280,8 +6151,7 @@ TEST_F(HeartbeatResponseHighVerbosityTestV1,
         now()++,            // Time is left.
         Milliseconds(400),  // Spent 0.4 of the 0.5 second in the network.
         HostAndPort("host2"),
-        StatusWith<ReplSetHeartbeatResponse>(believesWeAreDownResponse),
-        OpTime());
+        StatusWith<ReplSetHeartbeatResponse>(believesWeAreDownResponse));
     stopCapturingLogMessages();
     ASSERT_NO_ACTION(action.getAction());
     ASSERT_EQUALS(1, countLogLinesContaining("host2:27017 thinks that we are down"));
diff --git a/src/mongo/shell/replsettest.js b/src/mongo/shell/replsettest.js
index 5848b2f288e..3df3c69cc0e 100644
--- a/src/mongo/shell/replsettest.js
+++ b/src/mongo/shell/replsettest.js
@@ -1241,10 +1241,17 @@ var ReplSetTest = function(opts) {
         let master = rst.getPrimary();
         let id = tojson(rst.nodeList());
 
-        // All nodes must be in primary/secondary state prior to this point. Perform a majority
-        // write to ensure there is a committed operation on the set. The commit point will
-        // propagate to all members and trigger a stable checkpoint on all persisted storage engines
-        // nodes.
+        // Algorithm precondition: All nodes must be in primary/secondary state.
+        //
+        // 1) Perform a majority write. This will guarantee the primary updates its commit point
+        //    to the value of this write.
+        //
+        // 2) Perform a second write. This will guarantee that all nodes will update their commit
+        //    point to a time that is >= the previous write. That will trigger a stable checkpoint
+        //    on all nodes.
+        // TODO(SERVER-33248): Remove this block. We should not need to prod the replica set to
+        // advance the commit point if the commit point being lagged is sufficient to choose a
+        // sync source.
         function advanceCommitPoint(master) {
             // Shadow 'db' so that we can call 'advanceCommitPoint' directly on the primary node.
             let db = master.getDB('admin');
@@ -1254,10 +1261,6 @@ var ReplSetTest = function(opts) {
                     "data": {"awaitLastStableCheckpointTimestamp": 1},
                     "writeConcern": {"w": "majority", "wtimeout": ReplSetTest.kDefaultTimeoutMS}
                 }));
-
-                // TODO(SERVER-36758): Remove the second write. We should not need to prod the
-                // replica set to advance the commit point once all nodes are running a version with
-                // SERVER-33248. This can be removed once the last stable version includes the fix.
                 assert.commandWorked(db.adminCommand(
                     {"appendOplogNote": 1, "data": {"awaitLastStableCheckpointTimestamp": 2}}));
             };