SERVER-24784 syncDoInitialSync maintains its own instance of BackgroundSync

3 files changed, 29 insertions, 27 deletions

diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index ef5fe93d4f4..58a83b41cb6 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -151,22 +151,8 @@ bool ReplicationCoordinatorExternalStateImpl::isInitialSyncFlagSet(OperationCont
 void ReplicationCoordinatorExternalStateImpl::startInitialSync(OnInitialSyncFinishedFn finished) {
     _initialSyncThread.reset(new stdx::thread{[finished, this]() {
         Client::initThreadIfNotAlready("initial sync");
-
-        // "_bgSync" should not be initialized before this.
-        invariant(!_bgSync);
-        {
-            auto txn = cc().makeOperationContext();
-            invariant(txn);
-            invariant(txn->getClient());
-            log() << "Starting replication fetcher thread";
-
-            // Start bgsync.
-            _bgSync.reset(new BackgroundSync(this, makeSteadyStateOplogBuffer(txn.get())));
-            _bgSync->startup(txn.get());
-        }
-
         // Do initial sync.
-        syncDoInitialSync(_bgSync.get());
+        syncDoInitialSync(this);
         finished();
     }});
 }
@@ -183,11 +169,11 @@ void ReplicationCoordinatorExternalStateImpl::runOnInitialSyncThread(
 }
 
 void ReplicationCoordinatorExternalStateImpl::startSteadyStateReplication(OperationContext* txn) {
-    if (!_bgSync) {
-        log() << "Starting replication fetcher thread";
-        _bgSync.reset(new BackgroundSync(this, makeSteadyStateOplogBuffer(txn)));
-        _bgSync->startup(txn);
-    }
+    invariant(!_bgSync);
+    log() << "Starting replication fetcher thread";
+    _bgSync = stdx::make_unique<BackgroundSync>(this, makeSteadyStateOplogBuffer(txn));
+    _bgSync->startup(txn);
+
     log() << "Starting replication applier threads";
     invariant(!_applierThread);
     _applierThread.reset(new stdx::thread(stdx::bind(&runSyncThread, _bgSync.get())));
diff --git a/src/mongo/db/repl/rs_initialsync.cpp b/src/mongo/db/repl/rs_initialsync.cpp
index 4a3f3e721a1..387a7f9a391 100644
--- a/src/mongo/db/repl/rs_initialsync.cpp
+++ b/src/mongo/db/repl/rs_initialsync.cpp
@@ -32,6 +32,8 @@
 
 #include "mongo/db/repl/rs_initialsync.h"
 
+#include <memory>
+
 #include "mongo/bson/timestamp.h"
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/auth/authorization_manager.h"
@@ -50,14 +52,17 @@
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/oplogreader.h"
 #include "mongo/db/repl/repl_client_info.h"
+#include "mongo/db/repl/replication_coordinator_external_state.h"
 #include "mongo/db/repl/replication_coordinator_global.h"
 #include "mongo/db/repl/storage_interface.h"
 #include "mongo/db/service_context.h"
+#include "mongo/stdx/memory.h"
 #include "mongo/util/exit.h"
 #include "mongo/util/fail_point_service.h"
 #include "mongo/util/log.h"
 #include "mongo/util/mongoutils/str.h"
 #include "mongo/util/net/socket_exception.h"
+#include "mongo/util/scopeguard.h"
 
 namespace mongo {
 namespace repl {
@@ -513,23 +518,34 @@ Status checkAdminDatabase(OperationContext* txn, Database* adminDb) {
     return Status::OK();
 }
 
-void syncDoInitialSync(BackgroundSync* bgsync) {
+void syncDoInitialSync(ReplicationCoordinatorExternalState* replicationCoordinatorExternalState) {
     stdx::unique_lock<stdx::mutex> lk(_initialSyncMutex, stdx::defer_lock);
     if (!lk.try_lock()) {
         uasserted(34474, "Initial Sync Already Active.");
     }
 
+    std::unique_ptr<BackgroundSync> bgsync;
     {
-        const ServiceContext::UniqueOperationContext txnPtr = cc().makeOperationContext();
-        OperationContext& txn = *txnPtr;
-        createOplog(&txn);
+        log() << "Starting replication fetcher thread for initial sync";
+        auto txn = cc().makeOperationContext();
+        bgsync = stdx::make_unique<BackgroundSync>(
+            replicationCoordinatorExternalState,
+            replicationCoordinatorExternalState->makeInitialSyncOplogBuffer(txn.get()));
+        bgsync->startup(txn.get());
+        createOplog(txn.get());
     }
+    ON_BLOCK_EXIT([&bgsync]() {
+        log() << "Stopping replication fetcher thread for initial sync";
+        auto txn = cc().makeOperationContext();
+        bgsync->shutdown(txn.get());
+        bgsync->join(txn.get());
+    });
 
     int failedAttempts = 0;
     while (failedAttempts < kMaxFailedAttempts) {
         try {
             // leave loop when successful
-            Status status = _initialSync(bgsync);
+            Status status = _initialSync(bgsync.get());
             if (status.isOK()) {
                 break;
             } else {
diff --git a/src/mongo/db/repl/rs_initialsync.h b/src/mongo/db/repl/rs_initialsync.h
index 4f8cd5e5017..204f492ef0d 100644
--- a/src/mongo/db/repl/rs_initialsync.h
+++ b/src/mongo/db/repl/rs_initialsync.h
@@ -35,13 +35,13 @@ class OperationContext;
 class Database;
 
 namespace repl {
-class BackgroundSync;
+class ReplicationCoordinatorExternalState;
 
 /**
  * Begins an initial sync of a node.  This drops all data, chooses a sync source,
  * and runs the cloner from that sync source.  The node's state is not changed.
  */
-void syncDoInitialSync(BackgroundSync* bgsync);
+void syncDoInitialSync(ReplicationCoordinatorExternalState* replicationCoordinatorExternalState);
 
 /**
  * Checks that the "admin" database contains a supported version of the auth data schema.