Refs codership/mysql-wsrep#33

  1. factored XID-related functions to a separate wsrep_xid.cc unit.
  2. refactored them to take refrences instead of pointers where appropriate
  3. implemented wsrep_get/set_SE_position to take wsrep_uuid_t and wsrep_seqno_t instead of XID
  4. call wsrep_set_SE_position() in wsrep_sst_received() to reinitialize SE checkpoint after SST was received, avoid assert() in setting code by first checking current position.

16 files changed, 292 insertions, 199 deletions

diff --git a/sql/CMakeLists.txt b/sql/CMakeLists.txt
index 26dfad83810..c28d475d274 100644
--- a/sql/CMakeLists.txt
+++ b/sql/CMakeLists.txt
@@ -44,12 +44,13 @@ ENDIF()
 
 IF(WITH_WSREP)
  SET(WSREP_SOURCES
+   wsrep_utils.cc
+   wsrep_xid.cc
    wsrep_check_opts.cc
    wsrep_hton.cc
    wsrep_mysqld.cc 
    wsrep_notify.cc
    wsrep_sst.cc
-   wsrep_utils.cc
    wsrep_var.cc
    wsrep_binlog.cc
    wsrep_applier.cc
diff --git a/sql/handler.cc b/sql/handler.cc
index 18cf61906a6..6a69af0b900 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -53,6 +53,7 @@
 
 #ifdef WITH_WSREP
 #include "wsrep_mysqld.h"
+#include "wsrep_xid.h"
 #endif
 /*
   While we have legacy_db_type, we have this array to
@@ -1468,7 +1469,7 @@ int ha_commit_trans(THD *thd, bool all)
   if (!error && wsrep_is_wsrep_xid(&thd->transaction.xid_state.xid))
   {
     // xid was rewritten by wsrep
-    xid= wsrep_xid_seqno(&thd->transaction.xid_state.xid);
+    xid= wsrep_xid_seqno(thd->transaction.xid_state.xid);
   }
 #endif // WITH_WSREP
   if (!is_real_trans)
@@ -1851,7 +1852,7 @@ static my_bool xarecover_handlerton(THD *unused, plugin_ref plugin,
       {
 #ifdef WITH_WSREP
         my_xid x=(wsrep_is_wsrep_xid(&info->list[i]) ?
-                  wsrep_xid_seqno(&info->list[i]) :
+                  wsrep_xid_seqno(info->list[i]) :
                   info->list[i].get_my_xid());
 #else
         my_xid x=info->list[i].get_my_xid();
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 29e9a9e7da9..a67674448c7 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -106,6 +106,7 @@
 #ifdef WITH_WSREP
 #include "wsrep_mysqld.h"
 #include "wsrep_thd.h"
+#include "wsrep_binlog.h"
 static void wsrep_mysql_parse(THD *thd, char *rawbuf, uint length,
                               Parser_state *parser_state);
 #endif /* WITH_WSREP */
diff --git a/sql/wsrep_applier.cc b/sql/wsrep_applier.cc
index 8e5c49332a7..9fdc3952f3f 100644
--- a/sql/wsrep_applier.cc
+++ b/sql/wsrep_applier.cc
@@ -1,4 +1,4 @@
-/* Copyright (C) 2013 Codership Oy <info@codership.com>
+/* Copyright (C) 2013-2015 Codership Oy <info@codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -13,11 +13,12 @@
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
 
+#include "wsrep_applier.h"
 #include "wsrep_priv.h"
 #include "wsrep_binlog.h" // wsrep_dump_rbr_buf()
+#include "wsrep_xid.h"
 
-#include "log_event.h" // EVENT_LEN_OFFSET, etc.
-#include "wsrep_applier.h"
+#include "log_event.h" // class THD, EVENT_LEN_OFFSET, etc.
 
 /*
   read the first event from (*buf). The size of the (*buf) is (*buf_len).
@@ -150,7 +151,7 @@ static wsrep_cb_status_t wsrep_apply_events(THD*        thd,
     thd->set_server_id(ev->server_id);
     thd->set_time();                            // time the query
     wsrep_xid_init(&thd->transaction.xid_state.xid,
-                   &thd->wsrep_trx_meta.gtid.uuid,
+                   thd->wsrep_trx_meta.gtid.uuid,
                    thd->wsrep_trx_meta.gtid.seqno);
     thd->lex->current_select= 0;
     if (!ev->when)
diff --git a/sql/wsrep_applier.h b/sql/wsrep_applier.h
index 816970db67c..424db466e53 100644
--- a/sql/wsrep_applier.h
+++ b/sql/wsrep_applier.h
@@ -16,7 +16,8 @@
 #ifndef WSREP_APPLIER_H
 #define WSREP_APPLIER_H
 
-#include <sys/types.h>
+#include <my_config.h>
+#include "../wsrep/wsrep_api.h"
 
 /* wsrep callback prototypes */
 
diff --git a/sql/wsrep_hton.cc b/sql/wsrep_hton.cc
index 284c9d26d62..144196aab2e 100644
--- a/sql/wsrep_hton.cc
+++ b/sql/wsrep_hton.cc
@@ -1,4 +1,4 @@
-/* Copyright 2008 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -19,6 +19,7 @@
 #include <sql_class.h>
 #include "wsrep_mysqld.h"
 #include "wsrep_binlog.h"
+#include "wsrep_xid.h"
 #include <cstdio>
 #include <cstdlib>
 
@@ -497,7 +498,7 @@ wsrep_run_wsrep_commit(THD *thd, handlerton *hton, bool all)
     if (thd->transaction.xid_state.xid.get_my_xid())
     {
       wsrep_xid_init(&thd->transaction.xid_state.xid,
-                     &thd->wsrep_trx_meta.gtid.uuid,
+                     thd->wsrep_trx_meta.gtid.uuid,
                      thd->wsrep_trx_meta.gtid.seqno);
     }
     DBUG_PRINT("wsrep", ("replicating commit success"));
diff --git a/sql/wsrep_mysqld.cc b/sql/wsrep_mysqld.cc
index 08698c6e9fa..7cfde65ebf1 100644
--- a/sql/wsrep_mysqld.cc
+++ b/sql/wsrep_mysqld.cc
@@ -1,4 +1,4 @@
-/* Copyright 2008-2013 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -23,6 +23,7 @@
 #include "wsrep_var.h"
 #include "wsrep_binlog.h"
 #include "wsrep_applier.h"
+#include "wsrep_xid.h"
 #include <cstdio>
 #include <cstdlib>
 #include "log_event.h"
@@ -158,63 +159,22 @@ static void wsrep_log_states (wsrep_log_level_t   const level,
   wsrep_log_cb (level, msg);
 }
 
-static my_bool set_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
-{
-  XID* xid= reinterpret_cast<XID*>(arg);
-  handlerton* hton= plugin_data(plugin, handlerton *);
-  if (hton->db_type == DB_TYPE_INNODB)
-  {
-    const wsrep_uuid_t* uuid(wsrep_xid_uuid(xid));
-    char uuid_str[40] = {0, };
-    wsrep_uuid_print(uuid, uuid_str, sizeof(uuid_str));
-    WSREP_DEBUG("Set WSREPXid for InnoDB:  %s:%lld",
-                uuid_str, (long long)wsrep_xid_seqno(xid));
-    hton->wsrep_set_checkpoint(hton, xid);
-  }
-  return FALSE;
-}
-
-void wsrep_set_SE_checkpoint(XID* xid)
-{
-  plugin_foreach(NULL, set_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, xid);
-}
-
-static my_bool get_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
-{
-  XID* xid= reinterpret_cast<XID*>(arg);
-  handlerton* hton= plugin_data(plugin, handlerton *);
-  if (hton->db_type == DB_TYPE_INNODB)
-  {
-    hton->wsrep_get_checkpoint(hton, xid);
-    const wsrep_uuid_t* uuid(wsrep_xid_uuid(xid));
-    char uuid_str[40] = {0, };
-    wsrep_uuid_print(uuid, uuid_str, sizeof(uuid_str));
-    WSREP_DEBUG("Read WSREPXid from InnoDB:  %s:%lld",
-                uuid_str, (long long)wsrep_xid_seqno(xid));
-
-  }
-  return FALSE;
-}
-
-void wsrep_get_SE_checkpoint(XID* xid)
-{
-  plugin_foreach(NULL, get_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, xid);
-}
-
 #ifdef GTID_SUPPORT
-void wsrep_init_sidno(const wsrep_uuid_t& uuid)
+void wsrep_init_sidno(const wsrep_uuid_t& wsrep_uuid)
 {
   /* generate new Sid map entry from inverted uuid */
   rpl_sid sid;
   wsrep_uuid_t ltid_uuid;
+
   for (size_t i= 0; i < sizeof(ltid_uuid.data); ++i)
   {
-      ltid_uuid.data[i] = ~local_uuid.data[i];
+      ltid_uuid.data[i] = ~wsrep_uuid.data[i];
   }
+
   sid.copy_from(ltid_uuid.data);
   global_sid_lock->wrlock();
   wsrep_sidno= global_sid_map->add_sid(sid);
-  WSREP_INFO("inited wsrep sidno %d", wsrep_sidno);
+  WSREP_INFO("Initialized wsrep sidno %d", wsrep_sidno);
   global_sid_lock->unlock();
 }
 #endif /* GTID_SUPPORT */
@@ -355,13 +315,11 @@ wsrep_view_handler_cb (void*                    app_ctx,
         local_seqno= view->state_id.seqno;
       }
       /* Init storage engine XIDs from first view */
-      XID xid;
-      wsrep_xid_init(&xid, &local_uuid, local_seqno);
-      wsrep_set_SE_checkpoint(&xid);
-      new_status= WSREP_MEMBER_JOINED;
+      wsrep_set_SE_checkpoint(local_uuid, local_seqno);
 #ifdef GTID_SUPPORT
       wsrep_init_sidno(local_uuid);
 #endif /* GTID_SUPPORT */
+      new_status= WSREP_MEMBER_JOINED;
     }
 
     // just some sanity check
@@ -471,38 +429,28 @@ static void wsrep_synced_cb(void* app_ctx)
 static void wsrep_init_position()
 {
   /* read XIDs from storage engines */
-  XID xid;
-  memset(&xid, 0, sizeof(xid));
-  xid.formatID= -1;
-  wsrep_get_SE_checkpoint(&xid);
+  wsrep_uuid_t uuid;
+  wsrep_seqno_t seqno;
+  wsrep_get_SE_checkpoint(uuid, seqno);
 
-  if (xid.formatID == -1)
+  if (!memcmp(&uuid, &WSREP_UUID_UNDEFINED, sizeof(wsrep_uuid_t)))
   {
     WSREP_INFO("Read nil XID from storage engines, skipping position init");
     return;
   }
-  else if (!wsrep_is_wsrep_xid(&xid))
-  {
-    WSREP_WARN("Read non-wsrep XID from storage engines, skipping position init");
-    return;
-  }
-
-  const wsrep_uuid_t* uuid= wsrep_xid_uuid(&xid);
-  const wsrep_seqno_t seqno= wsrep_xid_seqno(&xid);
 
   char uuid_str[40] = {0, };
-  wsrep_uuid_print(uuid, uuid_str, sizeof(uuid_str));
+  wsrep_uuid_print(&uuid, uuid_str, sizeof(uuid_str));
   WSREP_INFO("Initial position: %s:%lld", uuid_str, (long long)seqno);
 
-
   if (!memcmp(&local_uuid, &WSREP_UUID_UNDEFINED, sizeof(local_uuid)) &&
       local_seqno == WSREP_SEQNO_UNDEFINED)
   {
     // Initial state
-    local_uuid= *uuid;
+    local_uuid= uuid;
     local_seqno= seqno;
   }
-  else if (memcmp(&local_uuid, uuid, sizeof(local_uuid)) ||
+  else if (memcmp(&local_uuid, &uuid, sizeof(local_uuid)) ||
            local_seqno != seqno)
   {
     WSREP_WARN("Initial position was provided by configuration or SST, "
@@ -758,14 +706,12 @@ void wsrep_recover()
                uuid_str, (long long)local_seqno);
     return;
   }
-  XID xid;
-  memset(&xid, 0, sizeof(xid));
-  xid.formatID= -1;
-  wsrep_get_SE_checkpoint(&xid);
+  wsrep_uuid_t uuid;
+  wsrep_seqno_t seqno;
+  wsrep_get_SE_checkpoint(uuid, seqno);
   char uuid_str[40];
-  wsrep_uuid_print(wsrep_xid_uuid(&xid), uuid_str, sizeof(uuid_str));
-  WSREP_INFO("Recovered position: %s:%lld", uuid_str,
-             (long long)wsrep_xid_seqno(&xid));
+  wsrep_uuid_print(&uuid, uuid_str, sizeof(uuid_str));
+  WSREP_INFO("Recovered position: %s:%lld", uuid_str, (long long)seqno);
 }
 
 
@@ -1324,11 +1270,9 @@ static void wsrep_TOI_end(THD *thd) {
 
   WSREP_DEBUG("TO END: %lld, %d : %s", (long long)wsrep_thd_trx_seqno(thd),
               thd->wsrep_exec_mode, (thd->query()) ? thd->query() : "void");
-  
-  XID xid;
-  wsrep_xid_init(&xid, &thd->wsrep_trx_meta.gtid.uuid,
-                 thd->wsrep_trx_meta.gtid.seqno);
-  wsrep_set_SE_checkpoint(&xid);
+
+  wsrep_set_SE_checkpoint(thd->wsrep_trx_meta.gtid.uuid,
+                          thd->wsrep_trx_meta.gtid.seqno);
   WSREP_DEBUG("TO END: %lld, update seqno",
               (long long)wsrep_thd_trx_seqno(thd));
   
diff --git a/sql/wsrep_mysqld.h b/sql/wsrep_mysqld.h
index 4bd2489210a..79a16e5f8d1 100644
--- a/sql/wsrep_mysqld.h
+++ b/sql/wsrep_mysqld.h
@@ -1,4 +1,4 @@
-/* Copyright 2008-2013 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -321,13 +321,7 @@ int wsrep_create_trigger_query(THD *thd, uchar** buf, size_t* buf_len);
 int wsrep_create_event_query(THD *thd, uchar** buf, size_t* buf_len);
 int wsrep_alter_event_query(THD *thd, uchar** buf, size_t* buf_len);
 
-struct xid_t;
-void wsrep_get_SE_checkpoint(xid_t*);
-void wsrep_set_SE_checkpoint(xid_t*);
+#ifdef GTID_SUPPORT
 void wsrep_init_sidno(const wsrep_uuid_t&);
-void wsrep_xid_init(xid_t*, const wsrep_uuid_t*, wsrep_seqno_t);
-const wsrep_uuid_t* wsrep_xid_uuid(const xid_t*);
-wsrep_seqno_t wsrep_xid_seqno(const xid_t*);
-extern "C" int wsrep_is_wsrep_xid(const void* xid);
-
+#endif /* GTID_SUPPORT */
 #endif /* WSREP_MYSQLD_H */
diff --git a/sql/wsrep_priv.h b/sql/wsrep_priv.h
index 5c66587d757..30dce78c1a4 100644
--- a/sql/wsrep_priv.h
+++ b/sql/wsrep_priv.h
@@ -32,22 +32,20 @@ ssize_t wsrep_sst_prepare   (void** msg);
 wsrep_cb_status wsrep_sst_donate_cb (void* app_ctx,
                                      void* recv_ctx,
                                      const void* msg, size_t msg_len,
-                                     const wsrep_gtid_t* current_id,
+                                     const wsrep_gtid_t* state_id,
                                      const char* state, size_t state_len,
                                      bool bypass);
-extern unsigned int wsrep_check_ip (const char* addr);
-extern size_t wsrep_guess_ip (char* buf, size_t buf_len);
-extern size_t wsrep_guess_address(char* buf, size_t buf_len);
 
 extern wsrep_uuid_t  local_uuid;
 extern wsrep_seqno_t local_seqno;
 
 // a helper function
-extern void wsrep_sst_received(wsrep_t*, const wsrep_uuid_t*, wsrep_seqno_t,
-                               const void*, size_t);
+void wsrep_sst_received(wsrep_t*, const wsrep_uuid_t&, wsrep_seqno_t,
+                        const void*, size_t);
 /*! SST thread signals init thread about sst completion */
-extern void wsrep_sst_complete(const wsrep_uuid_t*, wsrep_seqno_t, bool);
+void wsrep_sst_complete(const wsrep_uuid_t*, wsrep_seqno_t, bool);
 
 void wsrep_notify_status (wsrep_member_status_t new_status,
                           const wsrep_view_info_t* view = 0);
+
 #endif /* WSREP_PRIV_H */
diff --git a/sql/wsrep_sst.cc b/sql/wsrep_sst.cc
index 0de4a474653..73fd9d9a0f5 100644
--- a/sql/wsrep_sst.cc
+++ b/sql/wsrep_sst.cc
@@ -1,4 +1,4 @@
-/* Copyright 2008-2012 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -26,6 +26,7 @@
 #include <sql_parse.h>
 #include "wsrep_priv.h"
 #include "wsrep_utils.h"
+#include "wsrep_xid.h"
 #include <cstdio>
 #include <cstdlib>
 
@@ -244,20 +245,42 @@ void wsrep_sst_complete (const wsrep_uuid_t* sst_uuid,
   mysql_mutex_unlock (&LOCK_wsrep_sst);
 }
 
-void wsrep_sst_received (wsrep_t*            const wsrep,
-                         const wsrep_uuid_t* const uuid,
-                         wsrep_seqno_t       const seqno,
-                         const void*         const state,
-                         size_t              const state_len)
+void wsrep_sst_received (wsrep_t* const      wsrep,
+                         const wsrep_uuid_t& uuid,
+                         wsrep_seqno_t const seqno,
+                         const void* const   state,
+                         size_t const        state_len)
 {
-    int const rcode(seqno < 0 ? seqno : 0);
-    wsrep_gtid_t const state_id = {
-        *uuid, (rcode ? WSREP_SEQNO_UNDEFINED : seqno)
-    };
+    wsrep_get_SE_checkpoint(local_uuid, local_seqno);
+
+    if (memcmp(&local_uuid, &uuid, sizeof(wsrep_uuid_t)) ||
+        local_seqno < seqno || seqno < 0)
+    {
+        wsrep_set_SE_checkpoint(uuid, seqno);
+        local_uuid = uuid;
+        local_seqno = seqno;
+    }
+    else if (local_seqno > seqno)
+    {
+        WSREP_WARN("SST postion is in the past: %lld, current: %lld. "
+                   "Can't continue.",
+                   (long long)seqno, (long long)local_seqno);
+        unireg_abort(1);
+    }
+
 #ifdef GTID_SUPPORT
-    wsrep_init_sidno(state_id.uuid);
+    wsrep_init_sidno(uuid);
 #endif /* GTID_SUPPORT */
-    wsrep->sst_received(wsrep, &state_id, state, state_len, rcode);
+
+    if (wsrep)
+    {
+        int const rcode(seqno < 0 ? seqno : 0);
+        wsrep_gtid_t const state_id = {
+            uuid, (rcode ? WSREP_SEQNO_UNDEFINED : seqno)
+        };
+
+        wsrep->sst_received(wsrep, &state_id, state, state_len, rcode);
+    }
 }
 
 // Let applier threads to continue
@@ -266,7 +289,7 @@ void wsrep_sst_continue ()
   if (sst_needed)
   {
     WSREP_INFO("Signalling provider to continue.");
-    wsrep_sst_received (wsrep, &local_uuid, local_seqno, NULL, 0);
+    wsrep_sst_received (wsrep, local_uuid, local_seqno, NULL, 0);
   }
 }
 
diff --git a/sql/wsrep_utils.cc b/sql/wsrep_utils.cc
index a62fc4ec2ed..7a87d38d430 100644
--- a/sql/wsrep_utils.cc
+++ b/sql/wsrep_utils.cc
@@ -1,4 +1,4 @@
-/* Copyright 2010 Codership Oy <http://www.codership.com>
+/* Copyright 2010-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -467,58 +467,3 @@ size_t wsrep_guess_ip (char* buf, size_t buf_len)
 
   return 0;
 }
-
-/*
- * WSREPXid
- */
-
-#define WSREP_XID_PREFIX "WSREPXid"
-#define WSREP_XID_PREFIX_LEN MYSQL_XID_PREFIX_LEN
-#define WSREP_XID_UUID_OFFSET 8
-#define WSREP_XID_SEQNO_OFFSET (WSREP_XID_UUID_OFFSET + sizeof(wsrep_uuid_t))
-#define WSREP_XID_GTRID_LEN (WSREP_XID_SEQNO_OFFSET + sizeof(wsrep_seqno_t))
-
-void wsrep_xid_init(XID* xid, const wsrep_uuid_t* uuid, wsrep_seqno_t seqno)
-{
-  xid->formatID= 1;
-  xid->gtrid_length= WSREP_XID_GTRID_LEN;
-  xid->bqual_length= 0;
-  memset(xid->data, 0, sizeof(xid->data));
-  memcpy(xid->data, WSREP_XID_PREFIX, WSREP_XID_PREFIX_LEN);
-  memcpy(xid->data + WSREP_XID_UUID_OFFSET, uuid, sizeof(wsrep_uuid_t));
-  memcpy(xid->data + WSREP_XID_SEQNO_OFFSET, &seqno, sizeof(wsrep_seqno_t));
-}
-
-const wsrep_uuid_t* wsrep_xid_uuid(const XID* xid)
-{
-  if (wsrep_is_wsrep_xid(xid))
-    return reinterpret_cast<const wsrep_uuid_t*>(xid->data
-                                                 + WSREP_XID_UUID_OFFSET);
-  else
-    return &WSREP_UUID_UNDEFINED;
-}
-
-wsrep_seqno_t wsrep_xid_seqno(const XID* xid)
-{
-
-  if (wsrep_is_wsrep_xid(xid))
-  {
-    wsrep_seqno_t seqno;
-    memcpy(&seqno, xid->data + WSREP_XID_SEQNO_OFFSET, sizeof(wsrep_seqno_t));
-    return seqno;
-  }
-  else
-  {
-    return WSREP_SEQNO_UNDEFINED;
-  }
-}
-
-extern
-int wsrep_is_wsrep_xid(const void* xid_ptr)
-{
-  const XID* xid= reinterpret_cast<const XID*>(xid_ptr);
-  return (xid->formatID      == 1                   &&
-          xid->gtrid_length  == WSREP_XID_GTRID_LEN &&
-          xid->bqual_length  == 0                   &&
-          !memcmp(xid->data, WSREP_XID_PREFIX, WSREP_XID_PREFIX_LEN));
-}
diff --git a/sql/wsrep_var.cc b/sql/wsrep_var.cc
index 87698576c44..00b9ce3e4e8 100644
--- a/sql/wsrep_var.cc
+++ b/sql/wsrep_var.cc
@@ -1,4 +1,4 @@
-/* Copyright 2008 Codership Oy <http://www.codership.com>
+/* Copyright 2008-2015 Codership Oy <http://www.codership.com>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -22,6 +22,7 @@
 #include <sql_acl.h>
 #include "wsrep_priv.h"
 #include "wsrep_thd.h"
+#include "wsrep_xid.h"
 #include <my_dir.h>
 #include <cstdio>
 #include <cstdlib>
@@ -140,29 +141,30 @@ err:
   return 1;
 }
 
-void wsrep_set_local_position (const char* value)
+static
+void wsrep_set_local_position(const char* const value, bool const sst)
 {
-  size_t value_len  = strlen (value);
-  size_t uuid_len   = wsrep_uuid_scan (value, value_len, &local_uuid);
+  size_t const value_len = strlen(value);
+  wsrep_uuid_t uuid;
+  size_t const uuid_len = wsrep_uuid_scan(value, value_len, &uuid);
+  wsrep_seqno_t const seqno = strtoll(value + uuid_len + 1, NULL, 10);
 
-  local_seqno = strtoll (value + uuid_len + 1, NULL, 10);
-
-  XID xid;
-  wsrep_xid_init(&xid, &local_uuid, local_seqno);
-  wsrep_set_SE_checkpoint(&xid);
-  WSREP_INFO ("wsrep_start_position var submitted: '%s'", wsrep_start_position);
+  if (sst) {
+    wsrep_sst_received (wsrep, uuid, seqno, NULL, 0);
+  } else {
+    // initialization
+    local_uuid = uuid;
+    local_seqno = seqno;
+  }
 }
 
 bool wsrep_start_position_update (sys_var *self, THD* thd, enum_var_type type)
 {
+  WSREP_INFO ("wsrep_start_position var submitted: '%s'",
+              wsrep_start_position);
   // since this value passed wsrep_start_position_check, don't check anything
   // here
-  wsrep_set_local_position (wsrep_start_position);
-
-  if (wsrep) {
-    wsrep_sst_received (wsrep, &local_uuid, local_seqno, NULL, 0);
-  }
-
+  wsrep_set_local_position (wsrep_start_position, true);
   return 0;
 }
 
@@ -175,7 +177,7 @@ void wsrep_start_position_init (const char* val)
     return;
   }
 
-  wsrep_set_local_position (val);
+  wsrep_set_local_position (val, false);
 }
 
 static bool refresh_provider_options()
@@ -212,7 +214,7 @@ static int wsrep_provider_verify (const char* provider_str)
     return 1;
 
   /* check that provider file exists */
-  bzero(&f_stat, sizeof(MY_STAT));
+  memset(&f_stat, 0, sizeof(MY_STAT));
   if (!my_stat(path, &f_stat, MYF(0)))
   {
     return 1;
diff --git a/sql/wsrep_xid.cc b/sql/wsrep_xid.cc
new file mode 100644
index 00000000000..056da5748b9
--- /dev/null
+++ b/sql/wsrep_xid.cc
@@ -0,0 +1,150 @@
+/* Copyright 2015 Codership Oy <http://www.codership.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+//! @file some utility functions and classes not directly related to replication
+
+#include "wsrep_xid.h"
+#include "sql_class.h"
+#include "wsrep_mysqld.h" // for logging macros
+
+/*
+ * WSREPXid
+ */
+
+#define WSREP_XID_PREFIX "WSREPXid"
+#define WSREP_XID_PREFIX_LEN MYSQL_XID_PREFIX_LEN
+#define WSREP_XID_UUID_OFFSET 8
+#define WSREP_XID_SEQNO_OFFSET (WSREP_XID_UUID_OFFSET + sizeof(wsrep_uuid_t))
+#define WSREP_XID_GTRID_LEN (WSREP_XID_SEQNO_OFFSET + sizeof(wsrep_seqno_t))
+
+void wsrep_xid_init(XID* xid, const wsrep_uuid_t& uuid, wsrep_seqno_t seqno)
+{
+  xid->formatID= 1;
+  xid->gtrid_length= WSREP_XID_GTRID_LEN;
+  xid->bqual_length= 0;
+  memset(xid->data, 0, sizeof(xid->data));
+  memcpy(xid->data, WSREP_XID_PREFIX, WSREP_XID_PREFIX_LEN);
+  memcpy(xid->data + WSREP_XID_UUID_OFFSET,  &uuid,  sizeof(wsrep_uuid_t));
+  memcpy(xid->data + WSREP_XID_SEQNO_OFFSET, &seqno, sizeof(wsrep_seqno_t));
+}
+
+int wsrep_is_wsrep_xid(const void* xid_ptr)
+{
+  const XID* xid= reinterpret_cast<const XID*>(xid_ptr);
+  return (xid->formatID      == 1                   &&
+          xid->gtrid_length  == WSREP_XID_GTRID_LEN &&
+          xid->bqual_length  == 0                   &&
+          !memcmp(xid->data, WSREP_XID_PREFIX, WSREP_XID_PREFIX_LEN));
+}
+
+const wsrep_uuid_t* wsrep_xid_uuid(const XID& xid)
+{
+  if (wsrep_is_wsrep_xid(&xid))
+    return reinterpret_cast<const wsrep_uuid_t*>(xid.data
+                                                 + WSREP_XID_UUID_OFFSET);
+  else
+    return &WSREP_UUID_UNDEFINED;
+}
+
+wsrep_seqno_t wsrep_xid_seqno(const XID& xid)
+{
+  if (wsrep_is_wsrep_xid(&xid))
+  {
+    wsrep_seqno_t seqno;
+    memcpy(&seqno, xid.data + WSREP_XID_SEQNO_OFFSET, sizeof(wsrep_seqno_t));
+    return seqno;
+  }
+  else
+  {
+    return WSREP_SEQNO_UNDEFINED;
+  }
+}
+
+static my_bool set_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
+{
+  XID* xid= static_cast<XID*>(arg);
+  handlerton* hton= plugin_data(plugin, handlerton *);
+
+  if (hton->db_type == DB_TYPE_INNODB)
+  {
+    const wsrep_uuid_t* uuid(wsrep_xid_uuid(*xid));
+    char uuid_str[40] = {0, };
+    wsrep_uuid_print(uuid, uuid_str, sizeof(uuid_str));
+    WSREP_DEBUG("Set WSREPXid for InnoDB:  %s:%lld",
+                uuid_str, (long long)wsrep_xid_seqno(*xid));
+    hton->wsrep_set_checkpoint(hton, xid);
+  }
+
+  return FALSE;
+}
+
+void wsrep_set_SE_checkpoint(XID& xid)
+{
+  plugin_foreach(NULL, set_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, &xid);
+}
+
+void wsrep_set_SE_checkpoint(const wsrep_uuid_t& uuid, wsrep_seqno_t seqno)
+{
+  XID xid;
+  wsrep_xid_init(&xid, uuid, seqno);
+  wsrep_set_SE_checkpoint(xid);
+}
+
+static my_bool get_SE_checkpoint(THD* unused, plugin_ref plugin, void* arg)
+{
+  XID* xid= reinterpret_cast<XID*>(arg);
+  handlerton* hton= plugin_data(plugin, handlerton *);
+
+  if (hton->db_type == DB_TYPE_INNODB)
+  {
+    hton->wsrep_get_checkpoint(hton, xid);
+    const wsrep_uuid_t* uuid(wsrep_xid_uuid(*xid));
+    char uuid_str[40] = {0, };
+    wsrep_uuid_print(uuid, uuid_str, sizeof(uuid_str));
+    WSREP_DEBUG("Read WSREPXid from InnoDB:  %s:%lld",
+                uuid_str, (long long)wsrep_xid_seqno(*xid));
+  }
+
+  return FALSE;
+}
+
+void wsrep_get_SE_checkpoint(XID& xid)
+{
+  plugin_foreach(NULL, get_SE_checkpoint, MYSQL_STORAGE_ENGINE_PLUGIN, &xid);
+}
+
+void wsrep_get_SE_checkpoint(wsrep_uuid_t& uuid, wsrep_seqno_t& seqno)
+{
+  uuid= WSREP_UUID_UNDEFINED;
+  seqno= WSREP_SEQNO_UNDEFINED;
+
+  XID xid;
+  memset(&xid, 0, sizeof(xid));
+  xid.formatID= -1;
+
+  wsrep_get_SE_checkpoint(xid);
+
+  if (xid.formatID == -1) return; // nil XID
+
+  if (!wsrep_is_wsrep_xid(&xid))
+  {
+    WSREP_WARN("Read non-wsrep XID from storage engines.");
+    return;
+  }
+
+  uuid= *wsrep_xid_uuid(xid);
+  seqno= wsrep_xid_seqno(xid);
+}
diff --git a/sql/wsrep_xid.h b/sql/wsrep_xid.h
new file mode 100644
index 00000000000..8a43e49c733
--- /dev/null
+++ b/sql/wsrep_xid.h
@@ -0,0 +1,33 @@
+/* Copyright (C) 2015 Codership Oy <info@codership.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program; if not, write to the Free Software Foundation, Inc.,
+   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */
+
+#ifndef WSREP_XID_H
+#define WSREP_XID_H
+
+#include <my_config.h>
+#include "../wsrep/wsrep_api.h"
+#include "handler.h" // XID typedef
+
+void wsrep_xid_init(xid_t*, const wsrep_uuid_t&, wsrep_seqno_t);
+int wsrep_is_wsrep_xid(const void* xid);
+const wsrep_uuid_t* wsrep_xid_uuid(const XID&);
+wsrep_seqno_t wsrep_xid_seqno(const XID&);
+
+//void wsrep_get_SE_checkpoint(XID&);             /* uncomment if needed */
+void wsrep_get_SE_checkpoint(wsrep_uuid_t&, wsrep_seqno_t&);
+//void wsrep_set_SE_checkpoint(XID&);             /* uncomment if needed */
+void wsrep_set_SE_checkpoint(const wsrep_uuid_t&, wsrep_seqno_t);
+
+#endif /* WSREP_UTILS_H */
diff --git a/storage/innobase/include/ha_prototypes.h b/storage/innobase/include/ha_prototypes.h
index 5ecaa33fb96..bc588c6ecf0 100644
--- a/storage/innobase/include/ha_prototypes.h
+++ b/storage/innobase/include/ha_prototypes.h
@@ -299,9 +299,8 @@ int wsrep_trx_order_before(void *thd1, void *thd2);
 int wsrep_innobase_mysql_sort(int mysql_type, uint charset_number,
 			      unsigned char* str, unsigned int str_length,
 			      unsigned int buf_length);
-int 
-wsrep_on(void *thd_ptr);
-extern "C" int wsrep_is_wsrep_xid(const void*);
+int wsrep_on(void *thd_ptr);
+int wsrep_is_wsrep_xid(const void*);
 #endif /* WITH_WSREP */
 /**********************************************************************//**
 Determines the connection character set.
diff --git a/storage/xtradb/include/ha_prototypes.h b/storage/xtradb/include/ha_prototypes.h
index 4ebaee3c89e..86ba7464905 100644
--- a/storage/xtradb/include/ha_prototypes.h
+++ b/storage/xtradb/include/ha_prototypes.h
@@ -298,9 +298,8 @@ int wsrep_trx_order_before(void *thd1, void *thd2);
 int wsrep_innobase_mysql_sort(int mysql_type, uint charset_number,
 			      unsigned char* str, unsigned int str_length,
 			      unsigned int buf_length);
-int 
-wsrep_on(void *thd_ptr);
-extern "C" int wsrep_is_wsrep_xid(const void*);
+int wsrep_on(void *thd_ptr);
+int wsrep_is_wsrep_xid(const void*);
 #endif /* WITH_WSREP */
 /**********************************************************************//**
 Determines the connection character set.