Initial RSU implementation.

dbsim/db_server_service.cpp

@@ -75,6 +75,11 @@ void db::server_service::log_view(const wsrep::view&)
     wsrep::log_info() << "View";
 }
 
+int db::server_service::wait_committing_transactions(int)
+{
+    throw wsrep::not_implemented_error();
+}
+
 void db::server_service::debug_sync(const char*)
 {
 

dbsim/db_server_service.hpp

@@ -29,6 +29,7 @@ namespace db
         void log_dummy_write_set(wsrep::client_state&, const wsrep::ws_meta&)
             override;
         void log_view(const wsrep::view&) override;
+        int wait_committing_transactions(int) override;
         void debug_sync(const char*) override;
     private:
         db::server& server_;

include/wsrep/client_state.hpp

@@ -81,10 +81,12 @@ namespace wsrep
             /** High priority mode */
             m_high_priority,
             /** Client is in total order isolation mode */
-            m_toi
+            m_toi,
+            /** Client is executing rolling schema upgrade */
+            m_rsu
         };
 
-        static const int mode_max_ = m_toi + 1;
+        static const int n_modes_ = m_rsu + 1;
         /**
          * Client state enumeration.
          *
@@ -443,6 +445,19 @@ namespace wsrep
          */
         int leave_toi();
 
+        /**
+         * Begin rolling schema upgrade operation.
+         *
+         * @param timeout Timeout in seconds to wait for committing
+         *        connections to finish.
+         */
+        int begin_rsu(int timeout);
+
+        /**
+         * End rolling schema upgrade operation.
+         */
+        int end_rsu();
+
         /**
          * Begin non-blocking operation.
          */
@@ -691,6 +706,7 @@ namespace wsrep
         case wsrep::client_state::m_replicating: return "replicating";
         case wsrep::client_state::m_high_priority: return "high priority";
         case wsrep::client_state::m_toi: return "toi";
+        case wsrep::client_state::m_rsu: return "rsu";
         }
         return "unknown";
     }

include/wsrep/server_service.hpp

@@ -125,6 +125,15 @@ namespace wsrep
                               const wsrep::gtid& gtid,
                               bool bypass) = 0;
 
+
+        /**
+         * Wait until committing transactions have completed.
+         * Prior calling this method the server should have been
+         * desynced from the group to disallow further transactions
+         * to start committing.
+         */
+        virtual int wait_committing_transactions(int timeout) = 0;
+
         /**
          * Provide a server level debug sync point for a caller.
          */

src/client_state.cpp

@@ -300,6 +300,51 @@ int wsrep::client_state::leave_toi()
     return ret;
 }
 
+int wsrep::client_state::begin_rsu(int timeout)
+{
+    if (server_state_.desync())
+    {
+        wsrep::log_warning() << "Failed to desync server";
+        return 1;
+    }
+    if (server_state_.server_service().wait_committing_transactions(timeout))
+    {
+        wsrep::log_warning() << "RSU failed due to pending transactions";
+        server_state_.resync();
+        return 1;
+    }
+    wsrep::seqno pause_seqno(server_state_.pause());
+    if (pause_seqno.is_undefined())
+    {
+        wsrep::log_warning() << "Failed to pause provider";
+        server_state_.resync();
+        return 1;
+    }
+    wsrep::log_info() << "Provider paused at: " << pause_seqno;
+    wsrep::unique_lock<wsrep::mutex> lock(mutex_);
+    toi_mode_ = mode_;
+    mode(lock, m_rsu);
+    return 0;
+}
+
+int wsrep::client_state::end_rsu()
+{
+    int ret(0);
+    try
+    {
+        server_state_.resume();
+        server_state_.resync();
+    }
+    catch (const wsrep::runtime_error& e)
+    {
+        wsrep::log_warning() << "End RSU failed: " << e.what();
+        ret = 1;
+    }
+    wsrep::unique_lock<wsrep::mutex> lock(mutex_);
+    mode(lock, toi_mode_);
+    return ret;
+}
+
 int wsrep::client_state::sync_wait(int timeout)
 {
     std::pair<wsrep::gtid, enum wsrep::provider::status> result(
@@ -382,12 +427,13 @@ void wsrep::client_state::mode(
     enum mode mode)
 {
     assert(lock.owns_lock());
-    static const char allowed[mode_max_][mode_max_] =
-        {   /* l  r  h  t */
-            {  0, 0, 0, 0 }, /* local */
-            {  0, 0, 1, 1 }, /* repl */
-            {  0, 1, 0, 1 }, /* high prio */
-            {  0, 1, 1, 0 }  /* toi */
+    static const char allowed[n_modes_][n_modes_] =
+        {   /* l  r  h  t  r */
+            {  0, 0, 0, 0, 0 }, /* local */
+            {  0, 0, 1, 1, 1 }, /* repl */
+            {  0, 1, 0, 1, 0 }, /* high prio */
+            {  0, 1, 1, 0, 0 }, /* toi */
+            {  0, 1, 0, 0, 0 }  /* rsu */
         };
     if (allowed[mode_][mode])
     {

test/mock_server_state.hpp

@@ -85,10 +85,6 @@ namespace wsrep
         }
         void log_view(const wsrep::view&) { }
 
-        // void on_connect(const wsrep::gtid& ) WSREP_OVERRIDE { }
-        // void wait_until_connected() WSREP_OVERRIDE { }
-        // void on_view(const wsrep::view&) WSREP_OVERRIDE { }
-        // void on_sync() WSREP_OVERRIDE { }
         bool sst_before_init() const WSREP_OVERRIDE
         { return sst_before_init_; }
         std::string sst_request() WSREP_OVERRIDE { return ""; }
@@ -102,6 +98,8 @@ namespace wsrep
             client_state.after_rollback();
         }
 
+        int wait_committing_transactions(int) WSREP_OVERRIDE { return 0; }
+
         void debug_sync(const char* sync_point) WSREP_OVERRIDE
         {
             if (sync_point_enabled_ == sync_point)