SERVER-61505 Remove WireVersion::RESUMABLE_INITIAL_SYNC

9 files changed, 30 insertions, 405 deletions

diff --git a/src/mongo/db/repl/all_database_cloner.cpp b/src/mongo/db/repl/all_database_cloner.cpp
index d18f67cc39f..b5856b7aef0 100644
--- a/src/mongo/db/repl/all_database_cloner.cpp
+++ b/src/mongo/db/repl/all_database_cloner.cpp
@@ -122,15 +122,6 @@ BaseCloner::AfterStageBehavior AllDatabaseCloner::connectStage() {
 }
 
 BaseCloner::AfterStageBehavior AllDatabaseCloner::getInitialSyncIdStage() {
-    auto wireVersion = static_cast<WireVersion>(getClient()->getMaxWireVersion());
-    {
-        stdx::lock_guard<InitialSyncSharedData> lk(*getSharedData());
-        getSharedData()->setSyncSourceWireVersion(lk, wireVersion);
-    }
-
-    // Wire versions prior to resumable initial sync don't have a sync source id.
-    if (wireVersion < WireVersion::RESUMABLE_INITIAL_SYNC)
-        return kContinueNormally;
     auto initialSyncId = getClient()->findOne(
         NamespaceString{ReplicationConsistencyMarkersImpl::kDefaultInitialSyncIdNamespace},
         BSONObj{});
diff --git a/src/mongo/db/repl/all_database_cloner_test.cpp b/src/mongo/db/repl/all_database_cloner_test.cpp
index b77caa19e47..ad8aa737c78 100644
--- a/src/mongo/db/repl/all_database_cloner_test.cpp
+++ b/src/mongo/db/repl/all_database_cloner_test.cpp
@@ -295,59 +295,7 @@ TEST_F(AllDatabaseClonerTest, RetriesListDatabasesButRollBackIdChanges) {
     ASSERT_EQ(Minutes(60), getSharedData()->getTotalTimeUnreachable(WithLock::withoutLock()));
 }
 
-TEST_F(AllDatabaseClonerTest, RetriesListDatabasesButSourceNodeIsDowngraded) {
-    _mockClient->setWireVersions(WireVersion::RESUMABLE_INITIAL_SYNC,
-                                 WireVersion::RESUMABLE_INITIAL_SYNC);
-    auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
-    _mockServer->setCommandReply("replSetGetRBID", fromjson("{ok:1, rbid:1}"));
-    _mockServer->setCommandReply("listDatabases", fromjson("{ok:1, databases:[]}"));
-
-    // Stop at the listDatabases stage.
-    auto timesEnteredBeforeStage = beforeStageFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'AllDatabaseCloner', stage: 'listDatabases'}"));
-
-    auto cloner = makeAllDatabaseCloner();
-
-    // Run the cloner in a separate thread.
-    stdx::thread clonerThread([&] {
-        Client::initThread("ClonerRunner");
-        ASSERT_NOT_OK(cloner->run());
-    });
-
-    // Wait until we get to the listDatabases stage.
-    beforeStageFailPoint->waitForTimesEntered(timesEnteredBeforeStage + 1);
-
-    // Bring the server down.
-    _mockServer->shutdown();
-
-    auto beforeRBIDFailPoint =
-        globalFailPointRegistry().find("hangBeforeCheckingRollBackIdClonerStage");
-    auto timesEnteredRBID = beforeRBIDFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'AllDatabaseCloner', stage: 'listDatabases'}"));
-    beforeStageFailPoint->setMode(FailPoint::off, 0);
-    beforeRBIDFailPoint->waitForTimesEntered(timesEnteredRBID + 1);
-    _clock.advance(Minutes(60));
-
-    // Bring the server up, but change the wire version to an older one.
-    LOGV2(21053, "Bringing mock server back up.");
-    _mockClient->setWireVersions(WireVersion::SHARDED_TRANSACTIONS,
-                                 WireVersion::SHARDED_TRANSACTIONS);
-    _mockServer->reboot();
-
-    // Allow the cloner to finish.
-    beforeRBIDFailPoint->setMode(FailPoint::off, 0);
-    clonerThread.join();
-
-    // Total retries and outage time should be available.
-    ASSERT_EQ(0, getSharedData()->getRetryingOperationsCount(WithLock::withoutLock()));
-    ASSERT_EQ(1, getSharedData()->getTotalRetries(WithLock::withoutLock()));
-    ASSERT_EQ(Minutes(60), getSharedData()->getTotalTimeUnreachable(WithLock::withoutLock()));
-}
-
 TEST_F(AllDatabaseClonerTest, RetriesListDatabasesButInitialSyncIdChanges) {
-    // Initial Sync Ids are not checked before wire version RESUMABLE_INITIAL_SYNC.
-    _mockClient->setWireVersions(WireVersion::RESUMABLE_INITIAL_SYNC,
-                                 WireVersion::RESUMABLE_INITIAL_SYNC);
     auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
     _mockServer->setCommandReply("replSetGetRBID", fromjson("{ok:1, rbid:1}"));
     _mockServer->setCommandReply("listDatabases", fromjson("{ok:1, databases:[]}"));
diff --git a/src/mongo/db/repl/collection_cloner.cpp b/src/mongo/db/repl/collection_cloner.cpp
index 08701e697f6..f38cb4e64c6 100644
--- a/src/mongo/db/repl/collection_cloner.cpp
+++ b/src/mongo/db/repl/collection_cloner.cpp
@@ -103,9 +103,6 @@ CollectionCloner::CollectionCloner(const NamespaceString& sourceNss,
     invariant(collectionOptions.uuid);
     _sourceDbAndUuid = NamespaceStringOrUUID(sourceNss.db().toString(), *collectionOptions.uuid);
     _stats.ns = _sourceNss.ns();
-
-    // Find out whether the sync source supports resumable queries.
-    _resumeSupported = (getClient()->getMaxWireVersion() >= WireVersion::RESUMABLE_INITIAL_SYNC);
 }
 
 BaseCloner::ClonerStages CollectionCloner::getStages() {
@@ -320,72 +317,32 @@ void CollectionCloner::runQuery() {
     // Non-resumable query.
     Query query;
 
-    if (_resumeSupported) {
-        if (_resumeToken) {
-            // Resume the query from where we left off.
-            LOGV2_DEBUG(21133, 1, "Collection cloner will resume the last successful query");
-            query.requestResumeToken(true).resumeAfter(_resumeToken.get());
-        } else {
-            // New attempt at a resumable query.
-            LOGV2_DEBUG(21134, 1, "Collection cloner will run a new query");
-            query.requestResumeToken(true);
-        }
-        query.hint(BSON("$natural" << 1));
+    if (_resumeToken) {
+        // Resume the query from where we left off.
+        LOGV2_DEBUG(21133, 1, "Collection cloner will resume the last successful query");
+        query.requestResumeToken(true).resumeAfter(_resumeToken.get());
+    } else {
+        // New attempt at a resumable query.
+        LOGV2_DEBUG(21134, 1, "Collection cloner will run a new query");
+        query.requestResumeToken(true);
     }
+    query.hint(BSON("$natural" << 1));
 
     // We reset this every time we retry or resume a query.
     // We distinguish the first batch from the rest so that we only store the remote cursor id
     // the first time we get it.
     _firstBatchOfQueryRound = true;
 
-    try {
-        getClient()->query_DEPRECATED(
-            [this](DBClientCursorBatchIterator& iter) { handleNextBatch(iter); },
-            _sourceDbAndUuid,
-            BSONObj{},
-            query,
-            nullptr /* fieldsToReturn */,
-            QueryOption_NoCursorTimeout | QueryOption_SecondaryOk |
-                (collectionClonerUsesExhaust ? QueryOption_Exhaust : 0),
-            _collectionClonerBatchSize,
-            ReadConcernArgs::kImplicitDefault);
-    } catch (...) {
-        auto status = exceptionToStatus();
-
-        // If the collection was dropped at any point, we can just move on to the next cloner.
-        // This applies to both resumable (4.4) and non-resumable (4.2) queries.
-        if (status == ErrorCodes::NamespaceNotFound) {
-            throw;  // This will re-throw the NamespaceNotFound, resulting in a clean exit.
-        }
-
-        // Wire version 4.2 only.
-        if (!_resumeSupported) {
-            // If we lost our cursor last round, the only time we can can continue is if we find out
-            // this round that the collection was dropped on the source (that scenario is covered
-            // right above). If that is not the case, then the cloner would have more work to do,
-            // but since we cannot resume the query, we must abort initial sync.
-            if (_lostNonResumableCursor) {
-                abortNonResumableClone(status);
-            }
-
-            // Collection has changed upstream. This will trigger the code block above next round,
-            // (unless we find out the collection was dropped via getting a NamespaceNotFound).
-            if (_queryStage.isCursorError(status)) {
-                LOGV2(21135,
-                      "Lost cursor during non-resumable query: {error}",
-                      "Lost cursor during non-resumable query",
-                      "error"_attr = status);
-                _lostNonResumableCursor = true;
-                throw;
-            }
-            // Any other errors (including network errors, but excluding NamespaceNotFound) result
-            // in immediate failure.
-            abortNonResumableClone(status);
-        }
-
-        // Re-throw all query errors for resumable (4.4) queries.
-        throw;
-    }
+    getClient()->query_DEPRECATED(
+        [this](DBClientCursorBatchIterator& iter) { handleNextBatch(iter); },
+        _sourceDbAndUuid,
+        BSONObj{},
+        query,
+        nullptr /* fieldsToReturn */,
+        QueryOption_NoCursorTimeout | QueryOption_SecondaryOk |
+            (collectionClonerUsesExhaust ? QueryOption_Exhaust : 0),
+        _collectionClonerBatchSize,
+        ReadConcernArgs::kImplicitDefault);
 }
 
 void CollectionCloner::handleNextBatch(DBClientCursorBatchIterator& iter) {
@@ -408,7 +365,7 @@ void CollectionCloner::handleNextBatch(DBClientCursorBatchIterator& iter) {
         uasserted(ErrorCodes::InitialSyncFailure, "Lost remote cursor");
     }
 
-    if (_firstBatchOfQueryRound && _resumeSupported) {
+    if (_firstBatchOfQueryRound) {
         // Store the cursorId of the remote cursor.
         _remoteCursorId = iter.getCursorId();
     }
@@ -433,10 +390,8 @@ void CollectionCloner::handleNextBatch(DBClientCursorBatchIterator& iter) {
         uassertStatusOK(newStatus);
     }
 
-    if (_resumeSupported) {
-        // Store the resume token for this batch.
-        _resumeToken = iter.getPostBatchResumeToken();
-    }
+    // Store the resume token for this batch.
+    _resumeToken = iter.getPostBatchResumeToken();
 
     initialSyncHangCollectionClonerAfterHandlingBatchResponse.executeIf(
         [&](const BSONObj&) {
@@ -511,18 +466,6 @@ void CollectionCloner::waitForDatabaseWorkToComplete() {
     _dbWorkTaskRunner.join();
 }
 
-// Throws.
-void CollectionCloner::abortNonResumableClone(const Status& status) {
-    invariant(!_resumeSupported);
-    LOGV2(21141,
-          "Error during non-resumable clone: {error}",
-          "Error during non-resumable clone",
-          "error"_attr = status);
-    std::string message = str::stream()
-        << "Collection clone failed and is not resumable. nss: " << _sourceNss;
-    uasserted(ErrorCodes::InitialSyncFailure, message);
-}
-
 CollectionCloner::Stats CollectionCloner::getStats() const {
     stdx::lock_guard<Latch> lk(_mutex);
     return _stats;
diff --git a/src/mongo/db/repl/collection_cloner.h b/src/mongo/db/repl/collection_cloner.h
index 5ca0057fba1..80d8a9d72bc 100644
--- a/src/mongo/db/repl/collection_cloner.h
+++ b/src/mongo/db/repl/collection_cloner.h
@@ -226,12 +226,6 @@ private:
      */
     void runQuery();
 
-    /**
-     * Used to terminate the clone when we encounter a fatal error during a non-resumable query.
-     * Throws.
-     */
-    void abortNonResumableClone(const Status& status);
-
     // All member variables are labeled with one of the following codes indicating the
     // synchronization rules for accessing them.
     //
@@ -266,9 +260,6 @@ private:
     // like _documentsToInsert, is destroyed after those threads exit.
     TaskRunner _dbWorkTaskRunner;  // (R)
 
-    // Does the sync source support resumable queries? (wire version 4.4+)
-    bool _resumeSupported = false;  // (X)
-
     // The resumeToken used to resume after network error.
     boost::optional<BSONObj> _resumeToken;  // (X)
 
diff --git a/src/mongo/db/repl/collection_cloner_test.cpp b/src/mongo/db/repl/collection_cloner_test.cpp
index 99bec69d0c2..64db34fd042 100644
--- a/src/mongo/db/repl/collection_cloner_test.cpp
+++ b/src/mongo/db/repl/collection_cloner_test.cpp
@@ -79,9 +79,6 @@ protected:
         };
         _storageInterface.createCollectionForBulkFn = _standardCreateCollectionFn;
 
-
-        _mockClient->setWireVersions(WireVersion::RESUMABLE_INITIAL_SYNC,
-                                     WireVersion::RESUMABLE_INITIAL_SYNC);
         _mockServer->assignCollectionUuid(_nss.ns(), _collUuid);
         _mockServer->setCommandReply("replSetGetRBID",
                                      BSON("ok" << 1 << "rbid" << getSharedData()->getRollBackId()));
@@ -146,17 +143,6 @@ class CollectionClonerTestResumable : public CollectionClonerTest {
     }
 };
 
-class CollectionClonerTestNonResumable : public CollectionClonerTest {
-    void setUp() final {
-        CollectionClonerTest::setUp();
-        // Set client wireVersion to 4.2, where we do not yet support resumable cloning.
-        _mockClient->setWireVersions(WireVersion::SHARDED_TRANSACTIONS,
-                                     WireVersion::SHARDED_TRANSACTIONS);
-        stdx::lock_guard<InitialSyncSharedData> lk(*getSharedData());
-        getSharedData()->setSyncSourceWireVersion(lk, WireVersion::SHARDED_TRANSACTIONS);
-    }
-};
-
 TEST_F(CollectionClonerTestResumable, CollectionClonerPassesThroughErrorFromCollStatsCommand) {
     auto cloner = makeCollectionCloner();
     cloner->setStopAfterStage_forTest("count");
@@ -581,73 +567,6 @@ TEST_F(CollectionClonerTestResumable, DoNotCreateIDIndexIfAutoIndexIdUsed) {
     ASSERT_EQ(collNss, _nss);
 }
 
-TEST_F(CollectionClonerTestNonResumable, NonResumableQuerySuccess) {
-    // Set client wireVersion to 4.2, where we do not yet support resumable cloning.
-    // Set up data for preliminary stages
-    auto idIndexSpec = BSON("v" << 1 << "key" << BSON("_id" << 1) << "name"
-                                << "_id_");
-    // The collection cloner pre-stage makes a remote call to collStats to store in-progress
-    // metrics.
-    setMockServerReplies(BSON("size" << 10),
-                         createCountResponse(3),
-                         createCursorResponse(_nss.ns(), BSON_ARRAY(_idIndexSpec)));
-
-    // Set up documents to be returned from upstream node.
-    _mockServer->insert(_nss.ns(), BSON("_id" << 1));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 2));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 3));
-
-    auto cloner = makeCollectionCloner();
-
-    ASSERT_OK(cloner->run());
-
-    ASSERT_EQUALS(3, _collectionStats->insertCount);
-    ASSERT_TRUE(_collectionStats->commitCalled);
-    auto stats = cloner->getStats();
-    ASSERT_EQUALS(3u, stats.documentsCopied);
-}
-
-TEST_F(CollectionClonerTestNonResumable, NonResumableQueryFailure) {
-    // Set up data for preliminary stages
-    auto idIndexSpec = BSON("v" << 1 << "key" << BSON("_id" << 1) << "name"
-                                << "_id_");
-    // The collection cloner pre-stage makes a remote call to collStats to store in-progress
-    // metrics.
-    setMockServerReplies(BSON("size" << 10),
-                         createCountResponse(3),
-                         createCursorResponse(_nss.ns(), BSON_ARRAY(_idIndexSpec)));
-
-    auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
-    auto timesEnteredBeforeStage = beforeStageFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    // Set up documents to be returned from upstream node.
-    _mockServer->insert(_nss.ns(), BSON("_id" << 1));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 2));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 3));
-
-    auto cloner = makeCollectionCloner();
-
-    // Run the cloner in a separate thread.
-    stdx::thread clonerThread([&] {
-        Client::initThread("ClonerRunner");
-        auto status = cloner->run();
-        ASSERT_EQUALS(ErrorCodes::InitialSyncFailure, status);
-        ASSERT_STRING_CONTAINS(status.reason(), "Collection clone failed and is not resumable");
-    });
-
-    // Wait until we get to the query stage.
-    beforeStageFailPoint->waitForTimesEntered(timesEnteredBeforeStage + 1);
-
-    // Bring the server down.
-    _mockServer->shutdown();
-
-    // Let us begin with the query stage.
-    beforeStageFailPoint->setMode(FailPoint::off, 0);
-
-    clonerThread.join();
-}
-
 // We will retry our query without having yet obtained a resume token.
 TEST_F(CollectionClonerTestResumable, ResumableQueryFailTransientlyBeforeFirstBatchRetrySuccess) {
     _mockServer->setCommandReply("replSetGetRBID", fromjson("{ok:1, rbid:1}"));
@@ -1087,147 +1006,6 @@ TEST_F(CollectionClonerTestResumable, ResumableQueryTwoResumes) {
     ASSERT_EQUALS(7u, stats.documentsCopied);
 }
 
-// We receive a QueryPlanKilled error, then a NamespaceNotFound error, indicating that the
-// collection no longer exists in the database.
-TEST_F(CollectionClonerTestNonResumable, NonResumableCursorErrorDropOK) {
-    // Set up data for preliminary stages
-    auto idIndexSpec = BSON("v" << 1 << "key" << BSON("_id" << 1) << "name"
-                                << "_id_");
-    setMockServerReplies(BSON("size" << 10),
-                         createCountResponse(3),
-                         createCursorResponse(_nss.ns(), BSON_ARRAY(idIndexSpec)));
-
-    auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
-    auto timesEnteredBeforeStage = beforeStageFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    auto beforeRetryFailPoint = globalFailPointRegistry().find("hangBeforeRetryingClonerStage");
-    auto timesEnteredBeforeRetry = beforeRetryFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    // Set up documents to be returned from upstream node.
-    _mockServer->insert(_nss.ns(), BSON("_id" << 1));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 2));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 3));
-
-    auto cloner = makeCollectionCloner();
-
-    // Run the cloner in a separate thread.
-    stdx::thread clonerThread([&] {
-        Client::initThread("ClonerRunner");
-        ASSERT_OK(cloner->run());
-    });
-
-    // Wait until we get to the query stage.
-    beforeStageFailPoint->waitForTimesEntered(timesEnteredBeforeStage + 1);
-
-    // This will cause the next batch to fail once (transiently), but we do not support resume.
-    auto failNextBatch = globalFailPointRegistry().find("mockCursorThrowErrorOnGetMore");
-    failNextBatch->setMode(FailPoint::nTimes, 1, fromjson("{errorType: 'QueryPlanKilled'}"));
-
-    // Let us begin with the query stage.
-    beforeStageFailPoint->setMode(FailPoint::off, 0);
-    beforeRetryFailPoint->waitForTimesEntered(timesEnteredBeforeRetry + 1);
-
-    // Follow-up the QueryPlanKilled error with a NamespaceNotFound.
-    failNextBatch->setMode(FailPoint::nTimes, 1, fromjson("{errorType: 'NamespaceNotFound'}"));
-
-    beforeRetryFailPoint->setMode(FailPoint::off, 0);
-    clonerThread.join();
-}
-
-// We receive an OperationFailed error, but the next error we receive is _not_ NamespaceNotFound,
-// which means the collection still exists in the database, but we cannot resume the query.
-TEST_F(CollectionClonerTestNonResumable, NonResumableCursorErrorThenOtherError) {
-    // Set up data for preliminary stages
-    auto idIndexSpec = BSON("v" << 1 << "key" << BSON("_id" << 1) << "name"
-                                << "_id_");
-    setMockServerReplies(BSON("size" << 10),
-                         createCountResponse(3),
-                         createCursorResponse(_nss.ns(), BSON_ARRAY(idIndexSpec)));
-
-    auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
-    auto timesEnteredBeforeStage = beforeStageFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    auto beforeRetryFailPoint = globalFailPointRegistry().find("hangBeforeRetryingClonerStage");
-    auto timesEnteredBeforeRetry = beforeRetryFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    // Set up documents to be returned from upstream node.
-    _mockServer->insert(_nss.ns(), BSON("_id" << 1));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 2));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 3));
-
-    auto cloner = makeCollectionCloner();
-
-    // Run the cloner in a separate thread.
-    stdx::thread clonerThread([&] {
-        Client::initThread("ClonerRunner");
-        auto status = cloner->run();
-        ASSERT_EQUALS(ErrorCodes::InitialSyncFailure, status);
-        ASSERT_STRING_CONTAINS(status.reason(), "Collection clone failed and is not resumable");
-    });
-
-    // Wait until we get to the query stage.
-    beforeStageFailPoint->waitForTimesEntered(timesEnteredBeforeStage + 1);
-
-    // This will cause the next batch to fail once (transiently), but we do not support resume.
-    auto failNextBatch = globalFailPointRegistry().find("mockCursorThrowErrorOnGetMore");
-    failNextBatch->setMode(FailPoint::nTimes, 1, fromjson("{errorType: 'OperationFailed'}"));
-
-    // Let us begin with the query stage.
-    beforeStageFailPoint->setMode(FailPoint::off, 0);
-    beforeRetryFailPoint->waitForTimesEntered(timesEnteredBeforeRetry + 1);
-
-    // Follow-up the QueryPlanKilled error with a NamespaceNotFound.
-    failNextBatch->setMode(FailPoint::nTimes, 1, fromjson("{errorType: 'UnknownError'}"));
-
-    beforeRetryFailPoint->setMode(FailPoint::off, 0);
-    clonerThread.join();
-}
-
-// We receive a CursorNotFound error, but the next query succeeds, indicating that the
-// collection still exists in the database, but we cannot resume the query.
-TEST_F(CollectionClonerTestNonResumable, NonResumableCursorErrorThenSuccessEqualsFailure) {
-    // Set up data for preliminary stages
-    auto idIndexSpec = BSON("v" << 1 << "key" << BSON("_id" << 1) << "name"
-                                << "_id_");
-    setMockServerReplies(BSON("size" << 10),
-                         createCountResponse(3),
-                         createCursorResponse(_nss.ns(), BSON_ARRAY(idIndexSpec)));
-
-    auto beforeStageFailPoint = globalFailPointRegistry().find("hangBeforeClonerStage");
-    auto timesEnteredBeforeStage = beforeStageFailPoint->setMode(
-        FailPoint::alwaysOn, 0, fromjson("{cloner: 'CollectionCloner', stage: 'query'}"));
-
-    // Set up documents to be returned from upstream node.
-    _mockServer->insert(_nss.ns(), BSON("_id" << 1));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 2));
-    _mockServer->insert(_nss.ns(), BSON("_id" << 3));
-
-    auto cloner = makeCollectionCloner();
-    cloner->setBatchSize_forTest(2);
-
-    // Run the cloner in a separate thread.
-    stdx::thread clonerThread([&] {
-        Client::initThread("ClonerRunner");
-        auto status = cloner->run();
-        ASSERT_EQUALS(ErrorCodes::InitialSyncFailure, status);
-        ASSERT_STRING_CONTAINS(status.reason(), "Collection clone failed and is not resumable");
-    });
-
-    // Wait until we get to the query stage.
-    beforeStageFailPoint->waitForTimesEntered(timesEnteredBeforeStage + 1);
-
-    // This will cause the next batch to fail once (transiently), but we do not support resume.
-    auto failNextBatch = globalFailPointRegistry().find("mockCursorThrowErrorOnGetMore");
-    failNextBatch->setMode(FailPoint::nTimes, 1, fromjson("{errorType: 'CursorNotFound'}"));
-
-    // Let us begin with the query stage. We let the next retry succeed this time.
-    beforeStageFailPoint->setMode(FailPoint::off, 0);
-    clonerThread.join();
-}
 
 }  // namespace repl
 }  // namespace mongo
diff --git a/src/mongo/db/repl/initial_sync_base_cloner.cpp b/src/mongo/db/repl/initial_sync_base_cloner.cpp
index c08d102ca9c..f91c75aa92d 100644
--- a/src/mongo/db/repl/initial_sync_base_cloner.cpp
+++ b/src/mongo/db/repl/initial_sync_base_cloner.cpp
@@ -104,27 +104,14 @@ void InitialSyncBaseCloner::handleStageAttemptFailed(BaseClonerStage* stage, Sta
 }
 
 Status InitialSyncBaseCloner::checkSyncSourceIsStillValid() {
+    auto status = checkInitialSyncIdIsUnchanged();
+    if (!status.isOK())
+        return status;
 
-    WireVersion wireVersion;
-    {
-        stdx::lock_guard<ReplSyncSharedData> lk(*getSharedData());
-        auto wireVersionOpt = getSharedData()->getSyncSourceWireVersion(lk);
-        // The wire version should always have been set by the time this is called.
-        invariant(wireVersionOpt);
-        wireVersion = *wireVersionOpt;
-    }
-    if (wireVersion >= WireVersion::RESUMABLE_INITIAL_SYNC) {
-        auto status = checkInitialSyncIdIsUnchanged();
-        if (!status.isOK())
-            return status;
-    }
     return checkRollBackIdIsUnchanged();
 }
 
 Status InitialSyncBaseCloner::checkInitialSyncIdIsUnchanged() {
-    uassert(ErrorCodes::InitialSyncFailure,
-            "Sync source was downgraded and no longer supports resumable initial sync",
-            getClient()->getMaxWireVersion() >= WireVersion::RESUMABLE_INITIAL_SYNC);
     BSONObj initialSyncId;
     try {
         initialSyncId = getClient()->findOne(
diff --git a/src/mongo/db/repl/initial_sync_cloner_test_fixture.cpp b/src/mongo/db/repl/initial_sync_cloner_test_fixture.cpp
index c0c407f3bc3..60142aa7ba2 100644
--- a/src/mongo/db/repl/initial_sync_cloner_test_fixture.cpp
+++ b/src/mongo/db/repl/initial_sync_cloner_test_fixture.cpp
@@ -53,7 +53,6 @@ InitialSyncSharedData* InitialSyncClonerTestFixture::getSharedData() {
 
 void InitialSyncClonerTestFixture::setInitialSyncId() {
     stdx::lock_guard<InitialSyncSharedData> lk(*getSharedData());
-    getSharedData()->setSyncSourceWireVersion(lk, WireVersion::RESUMABLE_INITIAL_SYNC);
     getSharedData()->setInitialSyncSourceId(lk, _initialSyncId);
 }
 
diff --git a/src/mongo/db/repl/initial_sync_shared_data.h b/src/mongo/db/repl/initial_sync_shared_data.h
index 0644f151997..e8d6a9d1722 100644
--- a/src/mongo/db/repl/initial_sync_shared_data.h
+++ b/src/mongo/db/repl/initial_sync_shared_data.h
@@ -61,20 +61,6 @@ public:
     }
 
     /**
-     * Sets the wire version of the sync source.
-     */
-    void setSyncSourceWireVersion(WithLock, WireVersion wireVersion) {
-        _syncSourceWireVersion = wireVersion;
-    }
-
-    /**
-     * Returns the wire version of the sync source, if previously set.
-     */
-    boost::optional<WireVersion> getSyncSourceWireVersion(WithLock) {
-        return _syncSourceWireVersion;
-    }
-
-    /**
      * Sets the initial sync ID of the sync source.
      */
     void setInitialSyncSourceId(WithLock, boost::optional<UUID> syncSourceId) {
@@ -209,9 +195,6 @@ private:
     // Operation that may currently be retrying.
     RetryableOperation _retryableOp;
 
-    // The sync source wire version at the start of data cloning.
-    boost::optional<WireVersion> _syncSourceWireVersion;
-
     // The initial sync ID on the source at the start of data cloning.
     boost::optional<UUID> _initialSyncSourceId;
 };
diff --git a/src/mongo/db/repl/initial_syncer_test.cpp b/src/mongo/db/repl/initial_syncer_test.cpp
index 8d304ba1ebf..3875c64ef9b 100644
--- a/src/mongo/db/repl/initial_syncer_test.cpp
+++ b/src/mongo/db/repl/initial_syncer_test.cpp
@@ -51,6 +51,7 @@
 #include "mongo/db/repl/oplog_fetcher_mock.h"
 #include "mongo/db/repl/optime.h"
 #include "mongo/db/repl/repl_server_parameters_gen.h"
+#include "mongo/db/repl/replication_consistency_markers_impl.h"
 #include "mongo/db/repl/replication_consistency_markers_mock.h"
 #include "mongo/db/repl/replication_process.h"
 #include "mongo/db/repl/replication_recovery_mock.h"
@@ -385,6 +386,10 @@ protected:
         _mockServer->setCommandReply("listDatabases", makeListDatabasesResponse({}));
         _options1.uuid = UUID::gen();
 
+        _mockServer->insert(
+            ReplicationConsistencyMarkersImpl::kDefaultInitialSyncIdNamespace.toString(),
+            BSON("_id" << UUID::gen()));
+
         reset();
 
         launchExecutorThread();