diff --git a/dbsim/CMakeLists.txt b/dbsim/CMakeLists.txt
index b0cd756..30245e5 100644
--- a/dbsim/CMakeLists.txt
+++ b/dbsim/CMakeLists.txt
@@ -5,6 +5,7 @@
 add_executable(dbsim
   db_client.cpp
   db_client_service.cpp
+  db_high_priority_service.cpp
   db_params.cpp
   db_server.cpp
   db_server_service.cpp
diff --git a/dbsim/db_client.hpp b/dbsim/db_client.hpp
index b331e29..2057d9c 100644
--- a/dbsim/db_client.hpp
+++ b/dbsim/db_client.hpp
@@ -11,7 +11,7 @@
 #include "db_storage_engine.hpp"
 #include "db_client_state.hpp"
 #include "db_client_service.hpp"
-
+#include "db_high_priority_service.hpp"
 
 namespace db
 {
@@ -47,6 +47,7 @@ namespace db
     private:
         friend class db::server_state;
         friend class db::client_service;
+        friend class db::high_priority_service;
         template <class F> int client_command(F f);
         void run_one_transaction();
         void reset_error();
diff --git a/dbsim/db_client_service.cpp b/dbsim/db_client_service.cpp
index fa4c4f4..24aa0d4 100644
--- a/dbsim/db_client_service.cpp
+++ b/dbsim/db_client_service.cpp
@@ -3,20 +3,9 @@
 //
 
 #include "db_client_service.hpp"
+#include "db_high_priority_service.hpp"
 #include "db_client.hpp"
 
-int db::client_service::apply_write_set(const wsrep::const_buffer&)
-{
-    db::client* client(client_state_.client());
-    client->se_trx_.start(client);
-    client->se_trx_.apply(client_state_.transaction());
-    return 0;
-}
-
-int db::client_service::apply_toi(const wsrep::const_buffer&)
-{
-    return 0;
-}
 
 int db::client_service::commit(const wsrep::ws_handle&,
                                const wsrep::ws_meta&)
@@ -44,9 +33,11 @@ enum wsrep::provider::status
 db::client_service::replay()
 {
     wsrep::high_priority_context high_priority_context(client_state_);
+    db::high_priority_service high_priority_service(
+        client_state_.client()->server_, client_state_.client());
     auto ret(client_state_.provider().replay(
                  client_state_.transaction().ws_handle(),
-                 &client_state_));
+                 &high_priority_service));
     if (ret == wsrep::provider::success)
     {
         ++client_state_.client()->stats_.replays;
diff --git a/dbsim/db_client_service.hpp b/dbsim/db_client_service.hpp
index ecf174a..72b72c4 100644
--- a/dbsim/db_client_service.hpp
+++ b/dbsim/db_client_service.hpp
@@ -69,9 +69,9 @@ namespace db
         void remove_fragments() override
         { }
 
-        int apply_write_set(const wsrep::const_buffer&) override;
+        // int apply_write_set(const wsrep::const_buffer&) override;
 
-        int apply_toi(const wsrep::const_buffer&) override;
+        // int apply_toi(const wsrep::const_buffer&) override;
 
         int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) override;
 
diff --git a/dbsim/db_high_priority_service.cpp b/dbsim/db_high_priority_service.cpp
new file mode 100644
index 0000000..df64295
--- /dev/null
+++ b/dbsim/db_high_priority_service.cpp
@@ -0,0 +1,67 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#include "db_high_priority_service.hpp"
+#include "db_server.hpp"
+#include "db_client.hpp"
+
+int db::high_priority_service::apply(const wsrep::ws_handle& ws_handle,
+                                     const wsrep::ws_meta& ws_meta,
+                                     const wsrep::const_buffer& data)
+{
+    return server_.server_state().on_apply(*this, ws_handle, ws_meta, data);
+}
+
+int db::high_priority_service::start_transaction(
+    const wsrep::ws_handle& ws_handle,
+    const wsrep::ws_meta& ws_meta)
+{
+    return client_->client_state().start_transaction(ws_handle, ws_meta);
+}
+
+void db::high_priority_service::adopt_transaction(const wsrep::transaction&)
+{
+    throw wsrep::not_implemented_error();
+}
+
+int db::high_priority_service::apply_write_set(const wsrep::const_buffer&)
+{
+    client_->se_trx_.start(client_);
+    client_->se_trx_.apply(client_->client_state().transaction());
+    return 0;
+}
+
+int db::high_priority_service::apply_toi(const wsrep::const_buffer&)
+{
+    throw wsrep::not_implemented_error();
+}
+
+int db::high_priority_service::commit()
+{
+    int ret(client_->client_state_.before_commit());
+    if (ret == 0) client_->se_trx_.commit();
+    ret = ret || client_->client_state_.ordered_commit();
+    ret = ret || client_->client_state_.after_commit();
+    return ret;
+}
+
+int db::high_priority_service::rollback()
+{
+    int ret(client_->client_state_.before_rollback());
+    assert(ret == 0);
+    client_->se_trx_.rollback();
+    ret = client_->client_state_.after_rollback();
+    assert(ret == 0);
+    return ret;
+}
+
+void db::high_priority_service::after_apply()
+{
+    client_->client_state_.after_statement();
+}
+
+bool db::high_priority_service::is_replaying() const
+{
+    return (client_->client_state_.transaction().state() == wsrep::transaction::s_replaying);
+}
diff --git a/dbsim/db_high_priority_service.hpp b/dbsim/db_high_priority_service.hpp
new file mode 100644
index 0000000..e250729
--- /dev/null
+++ b/dbsim/db_high_priority_service.hpp
@@ -0,0 +1,46 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#ifndef WSREP_DB_HIGH_PRIORITY_SERVICE_HPP
+#define WSREP_DB_HIGH_PRIORITY_SERVICE_HPP
+
+#include "wsrep/high_priority_service.hpp"
+
+namespace db
+{
+    class server;
+    class client;
+    class high_priority_service : wsrep::high_priority_service
+    {
+    public:
+        high_priority_service(db::server& server, db::client* client)
+            : server_(server)
+            , client_(client)
+        { }
+
+        int apply(const wsrep::ws_handle&, const wsrep::ws_meta&,
+                  const wsrep::const_buffer&) override;
+        int start_transaction(const wsrep::ws_handle&,
+                              const wsrep::ws_meta&) override;
+        void adopt_transaction(const wsrep::transaction&) override;
+        int apply_write_set(const wsrep::const_buffer&) override;
+        int commit() override;
+        int rollback() override;
+        int apply_toi(const wsrep::const_buffer&) override;
+        void after_apply() override;
+        void store_globals() override { }
+        void reset_globals() override { }
+        int log_dummy_write_set(const wsrep::ws_handle&,
+                                const wsrep::ws_meta&)
+        { return 0; }
+        bool is_replaying() const;
+    private:
+        high_priority_service(const high_priority_service&);
+        high_priority_service& operator=(const high_priority_service&);
+        db::server& server_;
+        db::client* client_;
+    };
+}
+
+#endif // WSREP_DB_HIGH_PRIORITY_SERVICE_HPP
diff --git a/dbsim/db_server.cpp b/dbsim/db_server.cpp
index 002f253..b9cae18 100644
--- a/dbsim/db_server.cpp
+++ b/dbsim/db_server.cpp
@@ -4,6 +4,7 @@
 
 #include "db_server.hpp"
 #include "db_server_service.hpp"
+#include "db_high_priority_service.hpp"
 #include "db_client.hpp"
 #include "db_simulator.hpp"
 
@@ -34,11 +35,17 @@ void db::server::applier_thread()
                        wsrep::client_state::m_high_priority,
                        simulator_.params());
     wsrep::client_state* cc(static_cast<wsrep::client_state*>(
-                                  &applier.client_state()));
+                                &applier.client_state()));
+    db::high_priority_service hps(*this, &applier);
     cc->open(cc->id());
+    cc->before_command();
     enum wsrep::provider::status ret(
-        server_state_.provider().run_applier(cc));
+        server_state_.provider().run_applier(&hps));
     wsrep::log_info() << "Applier thread exited with error code " << ret;
+    cc->after_command_before_result();
+    cc->after_command_after_result();
+    cc->close();
+    cc->cleanup();
 }
 
 void db::server::start_applier()
@@ -112,15 +119,15 @@ wsrep::client_state* db::server::local_client_state()
                                       simulator_.params()));
     return &client->client_state();
 }
-
-wsrep::client_state* db::server::streaming_applier_client_state()
-{
-    throw wsrep::not_implemented_error();
-}
-
 void db::server::release_client_state(wsrep::client_state* client_state)
 {
     db::client_state* db_client_state(
         dynamic_cast<db::client_state*>(client_state));
     delete db_client_state->client();
 }
+
+wsrep::high_priority_service* db::server::streaming_applier_service()
+{
+    throw wsrep::not_implemented_error();
+}
+
diff --git a/dbsim/db_server.hpp b/dbsim/db_server.hpp
index ad89a9d..24e10bc 100644
--- a/dbsim/db_server.hpp
+++ b/dbsim/db_server.hpp
@@ -42,9 +42,8 @@ namespace db
         }
         void donate_sst(const std::string&, const  wsrep::gtid&, bool);
         wsrep::client_state* local_client_state();
-        wsrep::client_state* streaming_applier_client_state();
         void release_client_state(wsrep::client_state*);
-
+        wsrep::high_priority_service* streaming_applier_service();
     private:
         void start_client(size_t id);
 
diff --git a/dbsim/db_server_service.cpp b/dbsim/db_server_service.cpp
index bedef53..18116f3 100644
--- a/dbsim/db_server_service.cpp
+++ b/dbsim/db_server_service.cpp
@@ -6,6 +6,7 @@
 #include "db_server.hpp"
 
 #include "wsrep/logger.hpp"
+#include "wsrep/high_priority_service.hpp"
 
 db::server_service::server_service(db::server& server)
     : server_(server)
@@ -16,17 +17,23 @@ wsrep::client_state* db::server_service::local_client_state()
     return server_.local_client_state();
 }
 
-wsrep::client_state* db::server_service::streaming_applier_client_state()
-{
-    return server_.streaming_applier_client_state();
-}
-
 void db::server_service::release_client_state(
     wsrep::client_state* client_state)
 {
     server_.release_client_state(client_state);
 }
 
+wsrep::high_priority_service* db::server_service::streaming_applier_service()
+{
+    return server_.streaming_applier_service();
+}
+
+void db::server_service::release_high_priority_service(
+    wsrep::high_priority_service *high_priority_service)
+{
+    delete high_priority_service;
+}
+
 bool db::server_service::sst_before_init() const
 {
     return true;
diff --git a/dbsim/db_server_service.hpp b/dbsim/db_server_service.hpp
index 19c1ca8..4274b73 100644
--- a/dbsim/db_server_service.hpp
+++ b/dbsim/db_server_service.hpp
@@ -16,8 +16,10 @@ namespace db
     public:
         server_service(db::server& server);
         wsrep::client_state* local_client_state() override;
-        wsrep::client_state* streaming_applier_client_state() override;
         void release_client_state(wsrep::client_state*) override;
+        wsrep::high_priority_service* streaming_applier_service() override;
+        void release_high_priority_service(wsrep::high_priority_service*) override;
+
         bool sst_before_init() const override;
         int start_sst(const std::string&, const wsrep::gtid&, bool) override;
         std::string sst_request() override;
diff --git a/include/wsrep/client_service.hpp b/include/wsrep/client_service.hpp
index f97f791..64823cc 100644
--- a/include/wsrep/client_service.hpp
+++ b/include/wsrep/client_service.hpp
@@ -6,16 +6,12 @@
  *
  * This file will define a `callback` abstract interface for a
  * DBMS client session service. The interface will define methods
- * which will be called by the wsrep-lib under certain circumstances,
- * for example when a transaction rollback is required by internal
- * wsrep-lib operation or applier client needs to apply a write set.
+ * which will be called by the wsrep-lib.
  */
 
 #ifndef WSREP_CLIENT_SERVICE_HPP
 #define WSREP_CLIENT_SERVICE_HPP
 
-#include "transaction_termination_service.hpp"
-
 #include "buffer.hpp"
 #include "provider.hpp"
 #include "mutex.hpp"
@@ -24,7 +20,7 @@
 namespace wsrep
 {
     class transaction;
-    class client_service : public wsrep::transaction_termination_service
+    class client_service
     {
     public:
         client_service() { }
@@ -80,28 +76,15 @@ namespace wsrep
         virtual int prepare_fragment_for_replication(wsrep::mutable_buffer&) = 0;
         virtual void remove_fragments() = 0;
 
+        virtual int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) = 0;
         //
-        // Applying interface
+        // Rollback
         //
-
         /**
-         * Apply a write set.
-         *
-         * A write set applying happens always
-         * as a part of the transaction. The caller must start a
-         * new transaction before applying a write set and must
-         * either commit to make changes persistent or roll back.
+         * Roll back all transactions which are currently active
+         * in the client session.
          */
-        virtual int apply_write_set(const wsrep::const_buffer&) = 0;
-
-        /**
-         * Apply a TOI operation.
-         *
-         * TOI operation is a standalone operation and should not
-         * be executed as a part of a transaction.
-         */
-        virtual int apply_toi(const wsrep::const_buffer&) = 0;
-
+        virtual int rollback() = 0;
 
         //
         // Interface to global server state
diff --git a/include/wsrep/client_state.hpp b/include/wsrep/client_state.hpp
index 560ea61..2773c5e 100644
--- a/include/wsrep/client_state.hpp
+++ b/include/wsrep/client_state.hpp
@@ -391,7 +391,7 @@ namespace wsrep
             return transaction_.start_replaying(ws_meta);
         }
 
-        void adopt_transaction(wsrep::transaction& transaction)
+        void adopt_transaction(const wsrep::transaction& transaction)
         {
             assert(mode_ == m_high_priority);
             transaction_.start_transaction(transaction.id());
diff --git a/include/wsrep/high_priority_service.hpp b/include/wsrep/high_priority_service.hpp
new file mode 100644
index 0000000..4953de7
--- /dev/null
+++ b/include/wsrep/high_priority_service.hpp
@@ -0,0 +1,99 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+/** @file high_priority_service.hpp
+ *
+ * Interface for services for applying high priority transactions.
+ */
+#ifndef WSREP_HIGH_PRIORITY_SERVICE_HPP
+#define WSREP_HIGH_PRIORITY_SERVICE_HPP
+
+namespace wsrep
+{
+    class ws_handle;
+    class ws_meta;
+    class const_buffer;
+    class transaction;
+    class high_priority_service
+    {
+    public:
+        virtual ~high_priority_service() { }
+
+        virtual int apply(const ws_handle&, const ws_meta&,
+                          const const_buffer&) = 0;
+        /**
+         * Start a new transaction
+         */
+        virtual int start_transaction(const wsrep::ws_handle&,
+                                      const wsrep::ws_meta&) = 0;
+
+        /**
+         * Adopt a transaction.
+         */
+        virtual void adopt_transaction(const wsrep::transaction&) = 0;
+        /**
+         * Apply a write set.
+         *
+         * A write set applying happens always
+         * as a part of the transaction. The caller must start a
+         * new transaction before applying a write set and must
+         * either commit to make changes persistent or roll back.
+         */
+        virtual int apply_write_set(const wsrep::const_buffer&) = 0;
+
+        /**
+         * Commit a transaction.
+         */
+        virtual int commit() = 0;
+
+        /**
+         * Roll back a transaction
+         */
+        virtual int rollback() = 0;
+
+        /**
+         * Apply a TOI operation.
+         *
+         * TOI operation is a standalone operation and should not
+         * be executed as a part of a transaction.
+         */
+        virtual int apply_toi(const wsrep::const_buffer&) = 0;
+
+        /**
+         * Actions to take after applying a write set was completed.
+         */
+        virtual void after_apply() = 0;
+
+        virtual void store_globals() = 0;
+        virtual void reset_globals() = 0;
+
+        virtual int log_dummy_write_set(const ws_handle&, const ws_meta&) = 0;
+
+        virtual bool is_replaying() const = 0;
+    private:
+    };
+
+    class high_priority_switch
+    {
+    public:
+        high_priority_switch(high_priority_service& orig_service,
+                             high_priority_service& current_service)
+            : orig_service_(orig_service)
+            , current_service_(current_service)
+        {
+            orig_service_.reset_globals();
+            current_service_.store_globals();
+        }
+        ~high_priority_switch()
+        {
+            current_service_.reset_globals();
+            orig_service_.store_globals();
+        }
+    private:
+        high_priority_service& orig_service_;
+        high_priority_service& current_service_;
+    };
+}
+
+#endif // WSREP_HIGH_PRIORITY_SERVICE_HPP
diff --git a/include/wsrep/server_service.hpp b/include/wsrep/server_service.hpp
index d7ca9b8..c5deb3b 100644
--- a/include/wsrep/server_service.hpp
+++ b/include/wsrep/server_service.hpp
@@ -20,6 +20,7 @@
 namespace wsrep
 {
     class client_state;
+    class high_priority_service;
     class ws_meta;
     class gtid;
     class view;
@@ -36,19 +37,21 @@ namespace wsrep
          * @return Pointer to Client State.
          */
         virtual wsrep::client_state* local_client_state() = 0;
-
+        virtual void release_client_state(wsrep::client_state*) = 0;
         /**
          * Create an applier state for streaming transaction applying.
          *
          * @return Pointer to streaming applier client state.
          */
-        virtual wsrep::client_state* streaming_applier_client_state() = 0;
+        virtual wsrep::high_priority_service*
+        streaming_applier_service() = 0;
 
         /**
          * Release a client state allocated by either local_client_state()
          * or streaming_applier_client_state().
          */
-        virtual void release_client_state(wsrep::client_state*) = 0;
+        virtual void release_high_priority_service(
+            wsrep::high_priority_service*) = 0;
 
         /**
          * Perform a background rollback for a transaction.
diff --git a/include/wsrep/server_state.hpp b/include/wsrep/server_state.hpp
index dd78bd5..7a7036b 100644
--- a/include/wsrep/server_state.hpp
+++ b/include/wsrep/server_state.hpp
@@ -215,15 +215,16 @@ namespace wsrep
         void start_streaming_applier(
             const wsrep::id&,
             const wsrep::transaction_id&,
-            wsrep::client_state* client_state);
+            wsrep::high_priority_service*);
 
         void stop_streaming_applier(
             const wsrep::id&, const wsrep::transaction_id&);
         /**
          * Return reference to streaming applier.
          */
-        client_state* find_streaming_applier(const wsrep::id&,
-                                             const wsrep::transaction_id&) const;
+        wsrep::high_priority_service* find_streaming_applier(
+            const wsrep::id&,
+            const wsrep::transaction_id&) const;
         /**
          * Load WSRep provider.
          *
@@ -429,13 +430,13 @@ namespace wsrep
          *
          * @todo Make this private, allow calls for provider implementations
          *       only.
-         * @param client_state Applier client context.
+         * @param high_priority_service High priority applier service.
          * @param transaction Transaction context.
          * @param data Write set data
          *
          * @return Zero on success, non-zero on failure.
          */
-        int on_apply(wsrep::client_state& client_state,
+        int on_apply(wsrep::high_priority_service& high_priority_service,
                      const wsrep::ws_handle& ws_handle,
                      const wsrep::ws_meta& ws_meta,
                      const wsrep::const_buffer& data);
@@ -555,7 +556,7 @@ namespace wsrep
         size_t pause_count_;
         wsrep::seqno pause_seqno_;
         bool desynced_on_pause_;
-        typedef std::map<std::pair<wsrep::id, wsrep::transaction_id>, wsrep::client_state*> streaming_appliers_map;
+        typedef std::map<std::pair<wsrep::id, wsrep::transaction_id>, wsrep::high_priority_service*> streaming_appliers_map;
         streaming_appliers_map streaming_appliers_;
         wsrep::provider* provider_;
         std::string name_;
diff --git a/include/wsrep/transaction_termination_service.hpp b/include/wsrep/transaction_termination_service.hpp
deleted file mode 100644
index 886a377..0000000
--- a/include/wsrep/transaction_termination_service.hpp
+++ /dev/null
@@ -1,21 +0,0 @@
-//
-// Copyright (C) 2018 Codership Oy <info@codership.com>
-//
-
-
-#ifndef WSREP_TRANSACTION_TERMINATION_SERVICE_HPP
-#define WSREP_TRANSACTION_TERMINATION_SERVICE_HPP
-
-namespace wsrep
-{
-    class ws_handle;
-    class ws_meta;
-    class transaction_termination_service
-    {
-    public:
-        virtual int commit(const wsrep::ws_handle&, const wsrep::ws_meta&) = 0;
-        virtual int rollback() = 0;
-    };
-}
-
-#endif // WSREP_TRANSACTION_TERMINATION_SERVICE_HPP
diff --git a/src/server_state.cpp b/src/server_state.cpp
index 620c7bf..6b89562 100644
--- a/src/server_state.cpp
+++ b/src/server_state.cpp
@@ -3,7 +3,7 @@
 //
 
 #include "wsrep/server_state.hpp"
-#include "wsrep/client_state.hpp"
+#include "wsrep/high_priority_service.hpp"
 #include "wsrep/transaction.hpp"
 #include "wsrep/view.hpp"
 #include "wsrep/logger.hpp"
@@ -56,126 +56,95 @@ namespace
     }
 
     int apply_write_set(wsrep::server_state& server_state,
-                        wsrep::client_state& client_state,
+                        wsrep::high_priority_service& high_priority_service,
                         const wsrep::ws_handle& ws_handle,
                         const wsrep::ws_meta& ws_meta,
                         const wsrep::const_buffer& data)
     {
         int ret(0);
-        const wsrep::transaction& txc(client_state.transaction());
-        assert(client_state.mode() == wsrep::client_state::m_high_priority);
-
-        bool not_replaying(txc.state() !=
-                           wsrep::transaction::s_replaying);
-
         if (wsrep::starts_transaction(ws_meta.flags()) &&
             wsrep::commits_transaction(ws_meta.flags()))
         {
-            if (not_replaying)
-            {
-                client_state.before_command();
-                client_state.before_statement();
-                assert(txc.active() == false);
-                client_state.start_transaction(ws_handle, ws_meta);
-            }
-            else
-            {
-                client_state.start_replaying(ws_meta);
-            }
-
-            if (client_state.client_service().apply_write_set(data))
+            if (high_priority_service.start_transaction(ws_handle, ws_meta))
             {
                 ret = 1;
             }
-            else if (client_state.client_service().commit(ws_handle, ws_meta))
+            else if (high_priority_service.apply_write_set(data))
+            {
+                ret = 1;
+            }
+            else if (high_priority_service.commit())
             {
                 ret = 1;
             }
-
             if (ret)
             {
-                client_state.client_service().rollback();
+                high_priority_service.rollback();
             }
-
-            if (not_replaying)
-            {
-                client_state.after_statement();
-                client_state.after_command_before_result();
-                client_state.after_command_after_result();
-            }
-            assert(ret ||
-                   txc.state() == wsrep::transaction::s_committed);
+            high_priority_service.after_apply();
         }
         else if (wsrep::starts_transaction(ws_meta.flags()))
         {
-            assert(not_replaying);
             assert(server_state.find_streaming_applier(
                        ws_meta.server_id(), ws_meta.transaction_id()) == 0);
-            wsrep::client_state* sac(
-                server_state.server_service().streaming_applier_client_state());
+            wsrep::high_priority_service* sa(
+                server_state.server_service().streaming_applier_service());
             server_state.start_streaming_applier(
-                ws_meta.server_id(), ws_meta.transaction_id(), sac);
-            sac->start_transaction(ws_handle, ws_meta);
+                ws_meta.server_id(), ws_meta.transaction_id(), sa);
+            sa->start_transaction(ws_handle, ws_meta);
             {
-                // TODO: Client context switch will be ultimately
-                // implemented by the application. Therefore need to
-                // introduce a virtual method call which takes
-                // both original and sac client contexts as argument
-                // and a functor which does the applying.
-                wsrep::client_state_switch sw(client_state, *sac);
-                sac->before_command();
-                sac->before_statement();
-                sac->client_service().apply_write_set(data);
-                sac->after_statement();
-                sac->after_command_before_result();
-                sac->after_command_after_result();
+                wsrep::high_priority_switch sw(high_priority_service, *sa);
+                sa->apply_write_set(data);
+                sa->after_apply();
             }
-            server_state.server_service().log_dummy_write_set(client_state, ws_meta);
+            high_priority_service.log_dummy_write_set(ws_handle, ws_meta);
         }
         else if (ws_meta.flags() == 0)
         {
-            wsrep::client_state* sac(
+            wsrep::high_priority_service* sa(
                 server_state.find_streaming_applier(
                     ws_meta.server_id(), ws_meta.transaction_id()));
-            if (sac == 0)
+            if (sa == 0)
             {
                 // It is possible that rapid group membership changes
                 // may cause streaming transaction be rolled back before
                 // commit fragment comes in. Although this is a valid
                 // situation, log a warning if a sac cannot be found as
                 // it may be an indication of  a bug too.
+                assert(0);
                 wsrep::log_warning() << "Could not find applier context for "
                                      << ws_meta.server_id()
                                      << ": " << ws_meta.transaction_id();
             }
             else
             {
-                wsrep::client_state_switch(client_state, *sac);
-                sac->before_command();
-                sac->before_statement();
-                ret = sac->client_service().apply_write_set(data);
-                sac->after_statement();
-                sac->after_command_before_result();
-                sac->after_command_after_result();
+                wsrep::high_priority_switch(high_priority_service, *sa);
+                ret = sa->apply_write_set(data);
+                sa->after_apply();
             }
-            server_state.server_service().log_dummy_write_set(
-                client_state, ws_meta);
+            high_priority_service.log_dummy_write_set(
+                ws_handle, ws_meta);
         }
         else if (wsrep::commits_transaction(ws_meta.flags()))
         {
-            if (not_replaying)
+            if (high_priority_service.is_replaying())
             {
-                wsrep::client_state* sac(
+                ret = high_priority_service.apply_write_set(data) ||
+                    high_priority_service.commit();
+            }
+            else
+            {
+                wsrep::high_priority_service* sa(
                     server_state.find_streaming_applier(
                         ws_meta.server_id(), ws_meta.transaction_id()));
-                assert(sac);
-                if (sac == 0)
+                if (sa == 0)
                 {
                     // It is possible that rapid group membership changes
                     // may cause streaming transaction be rolled back before
                     // commit fragment comes in. Although this is a valid
                     // situation, log a warning if a sac cannot be found as
                     // it may be an indication of  a bug too.
+                    assert(0);
                     wsrep::log_warning()
                         << "Could not find applier context for "
                         << ws_meta.server_id()
@@ -183,40 +152,25 @@ namespace
                 }
                 else
                 {
-                    wsrep::client_state_switch(client_state, *sac);
-                    sac->before_command();
-                    sac->before_statement();
-                    ret = sac->client_service().commit(ws_handle, ws_meta);
-                    sac->after_statement();
-                    sac->after_command_before_result();
-                    sac->after_command_after_result();
+                    wsrep::high_priority_switch(high_priority_service, *sa);
+                    ret = sa->commit();
+                    sa->after_apply();
                     server_state.stop_streaming_applier(
                         ws_meta.server_id(), ws_meta.transaction_id());
-                    server_state.server_service().release_client_state(sac);
+                    server_state.server_service().release_high_priority_service(sa);
                 }
             }
-            else
-            {
-                ret = client_state.start_replaying(ws_meta) ||
-                    client_state.client_service().apply_write_set(
-                        wsrep::const_buffer()) ||
-                    client_state.client_service().commit(ws_handle, ws_meta);
-            }
         }
         else
         {
             // SR fragment applying not implemented yet
             assert(0);
         }
-        if (not_replaying)
-        {
-            assert(txc.active() == false);
-        }
         return ret;
     }
 
     int apply_toi(wsrep::provider& provider,
-                  wsrep::client_state& client_state,
+                  wsrep::high_priority_service& high_priority_service,
                   const wsrep::ws_handle& ws_handle,
                   const wsrep::ws_meta& ws_meta,
                   const wsrep::const_buffer& data)
@@ -226,9 +180,7 @@ namespace
         {
             // Regular toi
             provider.commit_order_enter(ws_handle, ws_meta);
-            client_state.enter_toi(ws_meta);
-            int ret(client_state.client_service().apply_toi(data));
-            client_state.leave_toi();
+            int ret(high_priority_service.apply_toi(data));
             provider.commit_order_leave(ws_handle, ws_meta);
             return ret;
         }
@@ -668,7 +620,7 @@ void wsrep::server_state::on_sync()
 }
 
 int wsrep::server_state::on_apply(
-    wsrep::client_state& client_state,
+    wsrep::high_priority_service& high_priority_service,
     const wsrep::ws_handle& ws_handle,
     const wsrep::ws_meta& ws_meta,
     const wsrep::const_buffer& data)
@@ -682,7 +634,8 @@ int wsrep::server_state::on_apply(
     }
     if (is_toi(ws_meta.flags()))
     {
-        return apply_toi(provider(), client_state, ws_handle, ws_meta, data);
+        return apply_toi(provider(), high_priority_service,
+                         ws_handle, ws_meta, data);
     }
     else if (is_commutative(ws_meta.flags()) || is_native(ws_meta.flags()))
     {
@@ -692,7 +645,7 @@ int wsrep::server_state::on_apply(
     }
     else
     {
-        return apply_write_set(*this, client_state,
+        return apply_write_set(*this, high_priority_service,
                                ws_handle, ws_meta, data);
     }
 }
@@ -700,14 +653,13 @@ int wsrep::server_state::on_apply(
 void wsrep::server_state::start_streaming_applier(
     const wsrep::id& server_id,
     const wsrep::transaction_id& transaction_id,
-    wsrep::client_state* client_state)
+    wsrep::high_priority_service* sa)
 {
     if (streaming_appliers_.insert(
             std::make_pair(std::make_pair(server_id, transaction_id),
-                           client_state)).second == false)
+                           sa)).second == false)
     {
         wsrep::log_error() << "Could not insert streaming applier";
-        delete client_state;
         throw wsrep::fatal_error();
     }
 }
@@ -730,7 +682,7 @@ void wsrep::server_state::stop_streaming_applier(
     }
 }
 
-wsrep::client_state* wsrep::server_state::find_streaming_applier(
+wsrep::high_priority_service* wsrep::server_state::find_streaming_applier(
     const wsrep::id& server_id,
     const wsrep::transaction_id& transaction_id) const
 {
diff --git a/src/transaction.cpp b/src/transaction.cpp
index deecd44..ff8ab8e 100644
--- a/src/transaction.cpp
+++ b/src/transaction.cpp
@@ -5,6 +5,7 @@
 #include "wsrep/transaction.hpp"
 #include "wsrep/client_state.hpp"
 #include "wsrep/server_state.hpp"
+#include "wsrep/high_priority_service.hpp"
 #include "wsrep/key.hpp"
 #include "wsrep/logger.hpp"
 #include "wsrep/compiler.hpp"
@@ -70,15 +71,22 @@ int wsrep::transaction::start_transaction(
     const wsrep::ws_handle& ws_handle,
     const wsrep::ws_meta& ws_meta)
 {
-    assert(ws_meta.flags());
-    assert(active() == false);
-    id_ = ws_meta.transaction_id();
-    assert(client_state_.mode() == wsrep::client_state::m_high_priority);
-    state_ = s_executing;
-    state_hist_.clear();
-    ws_handle_ = ws_handle;
-    ws_meta_ = ws_meta;
-    certified_ = true;
+    if (state() != s_replaying)
+    {
+        assert(ws_meta.flags());
+        assert(active() == false);
+        id_ = ws_meta.transaction_id();
+        assert(client_state_.mode() == wsrep::client_state::m_high_priority);
+        state_ = s_executing;
+        state_hist_.clear();
+        ws_handle_ = ws_handle;
+        ws_meta_ = ws_meta;
+        certified_ = true;
+    }
+    else
+    {
+        start_replaying(ws_meta);
+    }
     return 0;
 }
 
@@ -341,7 +349,14 @@ int wsrep::transaction::ordered_commit()
     assert(state() == s_committing);
     assert(ordered());
     int ret(provider().commit_order_leave(ws_handle_, ws_meta_));
-    // Should always succeed
+    // Should always succeed:
+    // 1) If before commit before succeeds, the transaction handle
+    //    in the provider is guaranteed to exist and the commit
+    //    has been ordered
+    // 2) The transaction which has been ordered for commit cannot be BF
+    //    aborted anymore
+    // 3) The provider should always guarantee that the transactions which
+    //    have been ordered for commit can finish committing.
     assert(ret == 0);
     state(lock, s_ordered_commit);
     debug_log_state("ordered_commit_leave");
@@ -939,11 +954,11 @@ int wsrep::transaction::certify_commit(
 void wsrep::transaction::streaming_rollback()
 {
     assert(streaming_context_.rolled_back() == false);
-    wsrep::client_state* sac(
-        server_service_.streaming_applier_client_state());
+    wsrep::high_priority_service* sa(
+        server_service_.streaming_applier_service());
     client_state_.server_state().start_streaming_applier(
-        client_state_.server_state().id(), id(), sac);
-    sac->adopt_transaction(*this);
+        client_state_.server_state().id(), id(), sa);
+    sa->adopt_transaction(*this);
     streaming_context_.cleanup();
     // Replicate rollback fragment
     provider().rollback(id_.get());
diff --git a/src/wsrep_provider_v26.cpp b/src/wsrep_provider_v26.cpp
index 87d084e..870d4b2 100644
--- a/src/wsrep_provider_v26.cpp
+++ b/src/wsrep_provider_v26.cpp
@@ -5,7 +5,7 @@
 #include "wsrep_provider_v26.hpp"
 
 #include "wsrep/server_state.hpp"
-#include "wsrep/client_state.hpp"
+#include "wsrep/high_priority_service.hpp"
 #include "wsrep/view.hpp"
 #include "wsrep/exception.hpp"
 #include "wsrep/logger.hpp"
@@ -355,10 +355,9 @@ namespace
                                const wsrep_trx_meta_t* meta,
                                wsrep_bool_t* exit_loop __attribute__((unused)))
     {
-        wsrep::client_state* client_state(
-            reinterpret_cast<wsrep::client_state*>(ctx));
-        assert(client_state);
-        assert(client_state->mode() == wsrep::client_state::m_high_priority);
+        wsrep::high_priority_service* high_priority_service(
+            reinterpret_cast<wsrep::high_priority_service*>(ctx));
+        assert(high_priority_service);
 
         wsrep::const_buffer data(buf->ptr, buf->len);
         wsrep::ws_handle ws_handle(wsh->trx_id, wsh->opaque);
@@ -373,8 +372,7 @@ namespace
             map_flags_from_native(flags));
         try
         {
-            if (client_state->server_state().on_apply(
-                    *client_state, ws_handle, ws_meta, data))
+            if (high_priority_service->apply(ws_handle, ws_meta, data))
             {
                 return WSREP_CB_FAILURE;
             }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 6c37933..d34d19f 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -3,6 +3,7 @@
 #
 
 add_executable(wsrep-lib_test
+  mock_high_priority_service.cpp
   mock_client_state.cpp
   test_utils.cpp
   id_test.cpp
diff --git a/test/mock_client_state.cpp b/test/mock_client_state.cpp
index 93ca4ad..7e1a82a 100644
--- a/test/mock_client_state.cpp
+++ b/test/mock_client_state.cpp
@@ -4,24 +4,7 @@
 
 #include "wsrep/transaction.hpp"
 #include "mock_client_state.hpp"
-
-
-int wsrep::mock_client_service::apply_write_set(
-    const wsrep::const_buffer&)
-
-{
-    assert(client_state_.toi_meta().seqno().is_undefined());
-    assert(client_state_.transaction().state() == wsrep::transaction::s_executing ||
-           client_state_.transaction().state() == wsrep::transaction::s_replaying);
-    return (fail_next_applying_ ? 1 : 0);
-}
-
-int wsrep::mock_client_service::apply_toi(const wsrep::const_buffer&)
-{
-    assert(client_state_.transaction().active() == false);
-    assert(client_state_.toi_meta().seqno().is_undefined() == false);
-    return (fail_next_toi_ ? 1 : 0);
-}
+#include "mock_high_priority_service.hpp"
 
 int wsrep::mock_client_service::commit(
     const wsrep::ws_handle&, const wsrep::ws_meta&)
@@ -61,3 +44,16 @@ int wsrep::mock_client_service::rollback()
     }
     return ret;
 }
+
+enum wsrep::provider::status
+wsrep::mock_client_service::replay() WSREP_OVERRIDE
+{
+    wsrep::mock_high_priority_service hps(client_state_.server_state(),
+                                          &client_state_, true);
+    enum wsrep::provider::status ret(
+        client_state_.provider().replay(
+            client_state_.transaction().ws_handle(),
+            &hps));
+    ++replays_;
+    return ret;
+}
diff --git a/test/mock_client_state.hpp b/test/mock_client_state.hpp
index aaf701f..e091353 100644
--- a/test/mock_client_state.hpp
+++ b/test/mock_client_state.hpp
@@ -46,8 +46,8 @@ namespace wsrep
             : wsrep::client_service()
             , is_autocommit_()
             , do_2pc_()
-            , fail_next_applying_()
-            , fail_next_toi_()
+              // , fail_next_applying_()
+              // , fail_next_toi_()
             , bf_abort_during_wait_()
             , error_during_prepare_data_()
             , killed_before_certify_()
@@ -89,16 +89,7 @@ namespace wsrep
         void will_replay() WSREP_OVERRIDE { }
 
         enum wsrep::provider::status
-        replay() WSREP_OVERRIDE
-        {
-            enum wsrep::provider::status ret(
-                client_state_.provider().replay(
-                    client_state_.transaction().ws_handle(),
-                    &client_state_));
-            ++replays_;
-            return ret;
-        }
-
+        replay() WSREP_OVERRIDE;
         void wait_for_replayers(
             wsrep::unique_lock<wsrep::mutex>& lock)
             WSREP_OVERRIDE
@@ -172,8 +163,8 @@ namespace wsrep
         //
         bool is_autocommit_;
         bool do_2pc_;
-        bool fail_next_applying_;
-        bool fail_next_toi_;
+        // bool fail_next_applying_;
+        // bool fail_next_toi_;
         bool bf_abort_during_wait_;
         bool error_during_prepare_data_;
         bool killed_before_certify_;
diff --git a/test/mock_high_priority_service.cpp b/test/mock_high_priority_service.cpp
new file mode 100644
index 0000000..27adfaa
--- /dev/null
+++ b/test/mock_high_priority_service.cpp
@@ -0,0 +1,67 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#include "mock_high_priority_service.hpp"
+#include "mock_server_state.hpp"
+
+int wsrep::mock_high_priority_service::apply(
+    const wsrep::ws_handle& ws_handle,
+    const wsrep::ws_meta& ws_meta,
+    const wsrep::const_buffer& data) WSREP_OVERRIDE
+{
+    return server_state_.on_apply(*this, ws_handle, ws_meta, data);
+}
+
+int wsrep::mock_high_priority_service::start_transaction(
+    const wsrep::ws_handle& ws_handle, const wsrep::ws_meta& ws_meta)
+{
+    return client_state_->start_transaction(ws_handle, ws_meta);
+}
+
+void wsrep::mock_high_priority_service::adopt_transaction(
+    const wsrep::transaction& transaction)
+{
+    client_state_->adopt_transaction(transaction);
+}
+
+int wsrep::mock_high_priority_service::apply_write_set(
+    const wsrep::const_buffer&)
+{
+    assert(client_state_->toi_meta().seqno().is_undefined());
+    assert(client_state_->transaction().state() == wsrep::transaction::s_executing ||
+           client_state_->transaction().state() == wsrep::transaction::s_replaying);
+    return (fail_next_applying_ ? 1 : 0);
+}
+
+int wsrep::mock_high_priority_service::commit()
+{
+
+    int ret(0);
+    if (client_state_->client_service().do_2pc())
+    {
+        ret = client_state_->before_prepare() ||
+            client_state_->after_prepare();
+    }
+    return (ret || client_state_->before_commit() ||
+            client_state_->ordered_commit() ||
+            client_state_->after_commit());
+}
+
+int wsrep::mock_high_priority_service::rollback()
+{
+    return (client_state_->before_rollback() ||
+            client_state_->after_rollback());
+}
+
+int wsrep::mock_high_priority_service::apply_toi(const wsrep::const_buffer&)
+{
+    assert(client_state_->transaction().active() == false);
+    assert(client_state_->toi_meta().seqno().is_undefined() == false);
+    return (fail_next_toi_ ? 1 : 0);
+}
+
+void wsrep::mock_high_priority_service::after_apply()
+{
+    client_state_->after_statement();
+}
diff --git a/test/mock_high_priority_service.hpp b/test/mock_high_priority_service.hpp
new file mode 100644
index 0000000..604a458
--- /dev/null
+++ b/test/mock_high_priority_service.hpp
@@ -0,0 +1,62 @@
+//
+// Copyright (C) 2018 Codership Oy <info@codership.com>
+//
+
+#ifndef WSREP_MOCK_HIGH_PRIORITY_SERVICE_HPP
+#define WSREP_MOCK_HIGH_PRIORITY_SERVICE_HPP
+
+#include "wsrep/high_priority_service.hpp"
+#include "mock_client_state.hpp"
+
+namespace wsrep
+{
+    class mock_high_priority_service : public wsrep::high_priority_service
+    {
+    public:
+        mock_high_priority_service(
+            wsrep::server_state& server_state,
+            wsrep::mock_client_state* client_state,
+            bool replaying)
+            : wsrep::high_priority_service()
+            , fail_next_applying_()
+            , fail_next_toi_()
+            , server_state_(server_state)
+            , client_state_(client_state)
+            , replaying_(replaying)
+        { }
+
+        int apply(const wsrep::ws_handle&,
+                  const wsrep::ws_meta&,
+                  const wsrep::const_buffer&) WSREP_OVERRIDE;
+
+        int start_transaction(const wsrep::ws_handle&, const wsrep::ws_meta&)
+            WSREP_OVERRIDE;
+
+        void adopt_transaction(const wsrep::transaction&) WSREP_OVERRIDE;
+        int apply_write_set(const wsrep::const_buffer&) WSREP_OVERRIDE;
+        int commit() WSREP_OVERRIDE;
+        int rollback() WSREP_OVERRIDE;
+        int apply_toi(const wsrep::const_buffer&) WSREP_OVERRIDE;
+        void after_apply() WSREP_OVERRIDE;
+        void store_globals() WSREP_OVERRIDE { }
+        void reset_globals() WSREP_OVERRIDE { }
+        int log_dummy_write_set(const wsrep::ws_handle&,
+                                const wsrep::ws_meta&)
+            WSREP_OVERRIDE { return 0; }
+        bool is_replaying() const WSREP_OVERRIDE { return replaying_; }
+        wsrep::mock_client_state* client_state()
+        {
+            return client_state_;
+        }
+        bool fail_next_applying_;
+        bool fail_next_toi_;
+    private:
+        mock_high_priority_service(const mock_high_priority_service&);
+        mock_high_priority_service& operator=(const mock_high_priority_service&);
+        wsrep::server_state& server_state_;
+        wsrep::mock_client_state* client_state_;
+        bool replaying_;
+    };
+}
+
+#endif // WSREP_MOCK_HIGH_PRIORITY_SERVICE_HPP
diff --git a/test/mock_provider.hpp b/test/mock_provider.hpp
index 5de04d1..4ba2b8e 100644
--- a/test/mock_provider.hpp
+++ b/test/mock_provider.hpp
@@ -8,6 +8,7 @@
 #include "wsrep/provider.hpp"
 #include "wsrep/logger.hpp"
 #include "wsrep/buffer.hpp"
+#include "wsrep/high_priority_service.hpp"
 
 #include <cstring>
 #include <map>
@@ -159,11 +160,13 @@ namespace wsrep
             return release_result_;
         }
 
-        enum wsrep::provider::status replay(const wsrep::ws_handle&,
+        enum wsrep::provider::status replay(const wsrep::ws_handle& ws_handle,
                                             void* ctx)
         {
-            wsrep::client_state& cc(
-                *static_cast<wsrep::client_state*>(ctx));
+            wsrep::mock_high_priority_service& high_priority_service(
+                *static_cast<wsrep::mock_high_priority_service*>(ctx));
+            wsrep::mock_client_state& cc(
+                *high_priority_service.client_state());
             wsrep::high_priority_context high_priority_context(cc);
             const wsrep::transaction& tc(cc.transaction());
             wsrep::ws_meta ws_meta;
@@ -191,8 +194,8 @@ namespace wsrep
                 return replay_result_;
             }
 
-            if (server_state_.on_apply(cc, tc.ws_handle(), ws_meta,
-                                         wsrep::const_buffer()))
+            if (high_priority_service.apply(ws_handle, ws_meta,
+                                            wsrep::const_buffer()))
             {
                 return wsrep::provider::error_fatal;
             }
diff --git a/test/mock_server_state.hpp b/test/mock_server_state.hpp
index 95dfaed..861d697 100644
--- a/test/mock_server_state.hpp
+++ b/test/mock_server_state.hpp
@@ -7,6 +7,7 @@
 
 #include "wsrep/server_state.hpp"
 #include "mock_client_state.hpp"
+#include "mock_high_priority_service.hpp"
 #include "mock_provider.hpp"
 
 #include "wsrep/compiler.hpp"
@@ -41,20 +42,37 @@ namespace wsrep
             ret->open(ret->id());
             return ret;
         }
-        wsrep::client_state* streaming_applier_client_state()
-        {
-            wsrep::client_state* ret(
-                new wsrep::mock_client(
-                    *this, ++last_client_id_,
-                    wsrep::client_state::m_high_priority));
-            ret->open(ret->id());
-            return ret;
-        }
-
         void release_client_state(wsrep::client_state* client_state)
         {
             delete client_state;
         }
+
+        wsrep::high_priority_service* streaming_applier_service()
+        {
+            wsrep::mock_client* cs(new wsrep::mock_client(
+                                       *this, ++last_client_id_,
+                                       wsrep::client_state::m_high_priority));
+            wsrep::mock_high_priority_service* ret(
+                new wsrep::mock_high_priority_service(*this, cs, false));
+            cs->open(cs->id());
+            cs->before_command();
+            return ret;
+        }
+
+        void release_high_priority_service(
+            wsrep::high_priority_service *high_priority_service)
+            WSREP_OVERRIDE
+        {
+            mock_high_priority_service* mhps(
+                dynamic_cast<mock_high_priority_service*>(high_priority_service));
+            wsrep::client_state* cs(mhps->client_state());
+            cs->after_command_before_result();
+            cs->after_command_after_result();
+            cs->close();
+            cs->cleanup();
+            delete cs;
+            delete mhps;
+        }
         void bootstrap() WSREP_OVERRIDE { }
         void log_message(enum wsrep::log::level level, const char* message)
         {
diff --git a/test/server_context_test.cpp b/test/server_context_test.cpp
index 9287230..b544b3b 100644
--- a/test/server_context_test.cpp
+++ b/test/server_context_test.cpp
@@ -16,6 +16,7 @@ namespace
             , cc(ss,
                  wsrep::client_id(1),
                  wsrep::client_state::m_high_priority)
+            , hps(ss, &cc, false)
             , ws_handle(1, (void*)1)
             , ws_meta(wsrep::gtid(wsrep::id("1"), wsrep::seqno(1)),
                       wsrep::stid(wsrep::id("1"), 1, 1),
@@ -24,9 +25,11 @@ namespace
                       wsrep::provider::flag::commit)
         {
             cc.open(cc.id());
+            cc.before_command();
         }
         wsrep::mock_server_state ss;
         wsrep::mock_client cc;
+        wsrep::mock_high_priority_service hps;
         wsrep::ws_handle ws_handle;
         wsrep::ws_meta ws_meta;
     };
@@ -56,7 +59,7 @@ BOOST_FIXTURE_TEST_CASE(server_state_applying_1pc,
                         applying_server_fixture)
 {
     char buf[1] = { 1 };
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer(buf, 1)) == 0);
     const wsrep::transaction& txc(cc.transaction());
     // ::abort();
@@ -70,7 +73,7 @@ BOOST_FIXTURE_TEST_CASE(server_state_applying_2pc,
                         applying_server_fixture)
 {
     char buf[1] = { 1 };
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer(buf, 1)) == 0);
     const wsrep::transaction& txc(cc.transaction());
     BOOST_REQUIRE(txc.state() == wsrep::transaction::s_committed);
@@ -81,9 +84,9 @@ BOOST_FIXTURE_TEST_CASE(server_state_applying_2pc,
 BOOST_FIXTURE_TEST_CASE(server_state_applying_1pc_rollback,
                         applying_server_fixture)
 {
-    cc.fail_next_applying_ = true;
+    hps.fail_next_applying_ = true;
     char buf[1] = { 1 };
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer(buf, 1)) == 1);
     const wsrep::transaction& txc(cc.transaction());
     BOOST_REQUIRE(txc.state() == wsrep::transaction::s_aborted);
@@ -94,9 +97,9 @@ BOOST_FIXTURE_TEST_CASE(server_state_applying_1pc_rollback,
 BOOST_FIXTURE_TEST_CASE(server_state_applying_2pc_rollback,
                         applying_server_fixture)
 {
-    cc.fail_next_applying_ = true;
+    hps.fail_next_applying_ = true;
     char buf[1] = { 1 };
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer(buf, 1)) == 1);
     const wsrep::transaction& txc(cc.transaction());
     BOOST_REQUIRE(txc.state() == wsrep::transaction::s_aborted);
@@ -109,13 +112,16 @@ BOOST_AUTO_TEST_CASE(server_state_streaming)
     wsrep::mock_client cc(ss,
                           wsrep::client_id(1),
                           wsrep::client_state::m_high_priority);
+    cc.debug_log_level(1);
+    wsrep::mock_high_priority_service hps(ss, &cc, false);
     wsrep::ws_handle ws_handle(1, (void*)1);
     wsrep::ws_meta ws_meta(wsrep::gtid(wsrep::id("1"), wsrep::seqno(1)),
                            wsrep::stid(wsrep::id("1"), 1, 1),
                            wsrep::seqno(0),
                            wsrep::provider::flag::start_transaction);
     cc.open(cc.id());
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(cc.before_command() == 0);
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer("1", 1)) == 0);
     BOOST_REQUIRE(ss.find_streaming_applier(
                       ws_meta.server_id(), ws_meta.transaction_id()));
@@ -123,13 +129,13 @@ BOOST_AUTO_TEST_CASE(server_state_streaming)
                              wsrep::stid(wsrep::id("1"), 1, 1),
                              wsrep::seqno(1),
                              0);
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer("1", 1)) == 0);
     ws_meta = wsrep::ws_meta(wsrep::gtid(wsrep::id("1"), wsrep::seqno(2)),
                              wsrep::stid(wsrep::id("1"), 1, 1),
                              wsrep::seqno(1),
                              wsrep::provider::flag::commit);
-    BOOST_REQUIRE(ss.on_apply(cc, ws_handle, ws_meta,
+    BOOST_REQUIRE(ss.on_apply(hps, ws_handle, ws_meta,
                               wsrep::const_buffer("1", 1)) == 0);
     BOOST_REQUIRE(ss.find_streaming_applier(
                       ws_meta.server_id(), ws_meta.transaction_id()) == 0);
diff --git a/test/transaction_test.cpp b/test/transaction_test.cpp
index dc40a70..5793f81 100644
--- a/test/transaction_test.cpp
+++ b/test/transaction_test.cpp
@@ -250,7 +250,7 @@ BOOST_FIXTURE_TEST_CASE_TEMPLATE(
     // Run before commit
     BOOST_REQUIRE(cc.before_commit());
     BOOST_REQUIRE(tc.state() == wsrep::transaction::s_must_abort);
-    BOOST_REQUIRE(cc.current_error() == wsrep::e_error_during_commit);
+    BOOST_REQUIRE(cc.current_error() == wsrep::e_size_exceeded_error);
     BOOST_REQUIRE(tc.certified() == false);
     BOOST_REQUIRE(tc.ordered() == false);