SERVER-37837 Get rid of TransactionReaper (Part 1)

This change gets rid of the TransactionReaper's usage of the
ReplicationCoordinator for checking whether it is primary or not and
makes the LogicalSessionCache joinable on shutdown.

It also removes the TransactionReaper's grouping per-shard optimization
and moves it all under SessionCollectionSharded.

1 files changed, 4 insertions, 20 deletions

diff --git a/src/mongo/db/logical_session_cache_factory_mongod.cpp b/src/mongo/db/logical_session_cache_factory_mongod.cpp
index 6610702c1ca..2d9870e258a 100644
--- a/src/mongo/db/logical_session_cache_factory_mongod.cpp
+++ b/src/mongo/db/logical_session_cache_factory_mongod.cpp
@@ -31,8 +31,6 @@
 
 #include "mongo/platform/basic.h"
 
-#include <memory>
-
 #include "mongo/db/logical_session_cache_factory_mongod.h"
 
 #include "mongo/db/logical_session_cache_impl.h"
@@ -41,14 +39,14 @@
 #include "mongo/db/sessions_collection_rs.h"
 #include "mongo/db/sessions_collection_sharded.h"
 #include "mongo/db/sessions_collection_standalone.h"
-#include "mongo/db/transaction_reaper.h"
+#include "mongo/db/transaction_reaper_d.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
 
 std::unique_ptr<LogicalSessionCache> makeLogicalSessionCacheD(LogicalSessionCacheServer state) {
-    auto liaison = stdx::make_unique<ServiceLiaisonMongod>();
+    auto liaison = std::make_unique<ServiceLiaisonMongod>();
 
     auto sessionsColl = [&]() -> std::shared_ptr<SessionsCollection> {
         switch (state) {
@@ -65,22 +63,8 @@ std::unique_ptr<LogicalSessionCache> makeLogicalSessionCacheD(LogicalSessionCach
         MONGO_UNREACHABLE;
     }();
 
-    auto reaper = [&]() -> std::shared_ptr<TransactionReaper> {
-        switch (state) {
-            case LogicalSessionCacheServer::kSharded:
-                return TransactionReaper::make(TransactionReaper::Type::kSharded, sessionsColl);
-            case LogicalSessionCacheServer::kReplicaSet:
-                return TransactionReaper::make(TransactionReaper::Type::kReplicaSet, sessionsColl);
-            case LogicalSessionCacheServer::kConfigServer:
-            case LogicalSessionCacheServer::kStandalone:
-                return nullptr;
-        }
-
-        MONGO_UNREACHABLE;
-    }();
-
-    return stdx::make_unique<LogicalSessionCacheImpl>(
-        std::move(liaison), std::move(sessionsColl), std::move(reaper));
+    return std::make_unique<LogicalSessionCacheImpl>(
+        std::move(liaison), std::move(sessionsColl), TransactionReaperD::reapSessionsOlderThan);
 }
 
 }  // namespace mongo