MDEV-18631 Fix streaming replication with wsrep_gtid_mode=ON

With wsrep_gtid_mode=ON, the appropriate commit hooks were not
called in all cases for applied streaming transactions.

As a fix, removed all special handling of commit order critical
section from Wsrep_high_priority_service and Wsrep_storage_service.
Now commit order critical section is always entered in ha_commit_trans().

Check for wsrep_run_commit_hook is now done in handler.cc, log.cc.
This makes it explicit that the transaction is an active wsrep
transaction which must go through commit hooks.

6 files changed, 160 insertions, 124 deletions

diff --git a/sql/handler.cc b/sql/handler.cc
index 7d2731b9a8f..58731fdcda7 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1207,8 +1207,9 @@ void trans_register_ha(THD *thd, bool all, handlerton *ht_arg)
 
 static int prepare_or_error(handlerton *ht, THD *thd, bool all)
 {
-  #ifdef WITH_WSREP
-  if (WSREP(thd) && ht->flags & HTON_WSREP_REPLICATION &&
+#ifdef WITH_WSREP
+  const bool run_wsrep_hooks= wsrep_run_commit_hook(thd, all);
+  if (run_wsrep_hooks && ht->flags & HTON_WSREP_REPLICATION &&
       wsrep_before_prepare(thd, all))
   {
     return(1);
@@ -1222,7 +1223,7 @@ static int prepare_or_error(handlerton *ht, THD *thd, bool all)
       my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
   }
 #ifdef WITH_WSREP
-  if (WSREP(thd) && ht->flags & HTON_WSREP_REPLICATION &&
+  if (run_wsrep_hooks && !err && ht->flags & HTON_WSREP_REPLICATION &&
       wsrep_after_prepare(thd, all))
   {
     err= 1;
@@ -1369,6 +1370,9 @@ int ha_commit_trans(THD *thd, bool all)
   Ha_trx_info *ha_info= trans->ha_list;
   bool need_prepare_ordered, need_commit_ordered;
   my_xid xid;
+#ifdef WITH_WSREP
+  const bool run_wsrep_hooks= wsrep_run_commit_hook(thd, all);
+#endif /* WITH_WSREP */
   DBUG_ENTER("ha_commit_trans");
   DBUG_PRINT("info",("thd: %p  option_bits: %lu  all: %d",
                      thd, (ulong) thd->variables.option_bits, all));
@@ -1424,7 +1428,7 @@ int ha_commit_trans(THD *thd, bool all)
     if (is_real_trans)
       thd->transaction.cleanup();
 #ifdef WITH_WSREP
-    if (WSREP(thd) && all && !error)
+    if (wsrep_is_active(thd) && is_real_trans && !error)
     {
       wsrep_commit_empty(thd, all);
     }
@@ -1519,11 +1523,7 @@ int ha_commit_trans(THD *thd, bool all)
       This commit will not go through log_and_order() where wsrep commit
       ordering is normally done. Commit ordering must be done here.
     */
-    bool run_wsrep_commit= (WSREP(thd)              &&
-                            rw_ha_count             &&
-                            wsrep_thd_is_local(thd) &&
-                            wsrep_has_changes(thd, all));
-    if (run_wsrep_commit)
+    if (run_wsrep_hooks)
       error= wsrep_before_commit(thd, all);
     if (error)
     {
@@ -1533,8 +1533,8 @@ int ha_commit_trans(THD *thd, bool all)
 #endif /* WITH_WSREP */
     error= ha_commit_one_phase(thd, all);
 #ifdef WITH_WSREP
-    if (run_wsrep_commit)
-      error= wsrep_after_commit(thd, all);
+    if (run_wsrep_hooks)
+      error= error || wsrep_after_commit(thd, all);
 #endif /* WITH_WSREP */
     goto done;
   }
@@ -1567,7 +1567,7 @@ int ha_commit_trans(THD *thd, bool all)
   DBUG_EXECUTE_IF("crash_commit_after_prepare", DBUG_SUICIDE(););
 
 #ifdef WITH_WSREP
-  if (!error && WSREP_ON)
+  if (run_wsrep_hooks && !error)
   {
     wsrep::seqno const s= wsrep_xid_seqno(thd->wsrep_xid);
     if (!s.is_undefined())
@@ -1584,7 +1584,7 @@ int ha_commit_trans(THD *thd, bool all)
     goto done;
   }
 #ifdef WITH_WSREP
-  if (wsrep_before_commit(thd, all))
+  if (run_wsrep_hooks && (error = wsrep_before_commit(thd, all)))
     goto wsrep_err;
 #endif /* WITH_WSREP */
   DEBUG_SYNC(thd, "ha_commit_trans_before_log_and_order");
@@ -1600,10 +1600,10 @@ int ha_commit_trans(THD *thd, bool all)
 
   error= commit_one_phase_2(thd, all, trans, is_real_trans) ? 2 : 0;
 #ifdef WITH_WSREP
-  if (error || wsrep_after_commit(thd, all))
+  if (run_wsrep_hooks && (error || (error = wsrep_after_commit(thd, all))))
   {
     mysql_mutex_lock(&thd->LOCK_thd_data);
-    if (thd->wsrep_trx().state() == wsrep::transaction::s_must_abort)
+    if (wsrep_must_abort(thd))
     {
       mysql_mutex_unlock(&thd->LOCK_thd_data);
       (void)tc_log->unlog(cookie, xid);
@@ -1636,7 +1636,7 @@ done:
 #ifdef WITH_WSREP
 wsrep_err:
   mysql_mutex_lock(&thd->LOCK_thd_data);
-  if (thd->wsrep_trx().state() == wsrep::transaction::s_must_abort)
+  if (run_wsrep_hooks && wsrep_must_abort(thd))
   {
     WSREP_DEBUG("BF abort has happened after prepare & certify");
     mysql_mutex_unlock(&thd->LOCK_thd_data);
@@ -1672,7 +1672,8 @@ end:
     thd->mdl_context.release_lock(mdl_request.ticket);
   }
 #ifdef WITH_WSREP
-  if (WSREP(thd) && all && !error && (rw_ha_count == 0))
+  if (wsrep_is_active(thd) && is_real_trans && !error && (rw_ha_count == 0) &&
+      wsrep_not_committed(thd))
   {
     wsrep_commit_empty(thd, all);
   }
diff --git a/sql/log.cc b/sql/log.cc
index a89be15a0d7..c7aa72f9dd0 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -7686,7 +7686,7 @@ MYSQL_BIN_LOG::write_transaction_to_binlog_events(group_commit_entry *entry)
 {
   int is_leader= queue_for_group_commit(entry);
 #ifdef WITH_WSREP
-  if (is_leader >= 0 &&
+  if (wsrep_run_commit_hook(entry->thd, true) && is_leader >= 0 &&
       wsrep_ordered_commit(entry->thd, entry->all, wsrep_apply_error()))
     return true;
 #endif /* WITH_WSREP */
diff --git a/sql/wsrep_high_priority_service.cc b/sql/wsrep_high_priority_service.cc
index 64fe4ce52fe..29fc4e3362e 100644
--- a/sql/wsrep_high_priority_service.cc
+++ b/sql/wsrep_high_priority_service.cc
@@ -195,7 +195,8 @@ int Wsrep_high_priority_service::start_transaction(
   const wsrep::ws_handle& ws_handle, const wsrep::ws_meta& ws_meta)
 {
   DBUG_ENTER(" Wsrep_high_priority_service::start_transaction");
-  DBUG_RETURN(m_thd->wsrep_cs().start_transaction(ws_handle, ws_meta));
+  DBUG_RETURN(m_thd->wsrep_cs().start_transaction(ws_handle, ws_meta) ||
+              trans_begin(m_thd));
 }
 
 const wsrep::transaction& Wsrep_high_priority_service::transaction() const
@@ -204,14 +205,23 @@ const wsrep::transaction& Wsrep_high_priority_service::transaction() const
   DBUG_RETURN(m_thd->wsrep_trx());
 }
 
-void Wsrep_high_priority_service::adopt_transaction(const wsrep::transaction& transaction)
+int Wsrep_high_priority_service::adopt_transaction(
+  const wsrep::transaction& transaction)
 {
   DBUG_ENTER(" Wsrep_high_priority_service::adopt_transaction");
+  /* Adopt transaction first to set up transaction meta data for
+     trans begin. If trans_begin() fails for some reason, roll back
+     the wsrep transaction before return. */
   m_thd->wsrep_cs().adopt_transaction(transaction);
-  DBUG_VOID_RETURN;
+  int ret= trans_begin(m_thd);
+  if (ret)
+  {
+    m_thd->wsrep_cs().before_rollback();
+    m_thd->wsrep_cs().after_rollback();
+  }
+  DBUG_RETURN(ret);
 }
 
-
 int Wsrep_high_priority_service::append_fragment_and_commit(
   const wsrep::ws_handle& ws_handle,
   const wsrep::ws_meta& ws_meta,
@@ -254,23 +264,8 @@ int Wsrep_high_priority_service::append_fragment_and_commit(
                                                 ws_meta, true);
   }
 
-  if (!ret)
-  {
-    DBUG_ASSERT(wsrep_thd_trx_seqno(m_thd) > 0);
-    if (!do_binlog_commit)
-    {
-      ret= wsrep_before_commit(m_thd, true);
-    }
-    ret= ret || trans_commit(m_thd);
-    if (!do_binlog_commit)
-    {
-      if (opt_log_slave_updates)
-      {
-        ret= ret || wsrep_ordered_commit(m_thd, true, wsrep_apply_error());
-      }
-      ret= ret || wsrep_after_commit(m_thd, true);
-    }
-  }
+  ret= ret || trans_commit(m_thd);
+
   m_thd->wsrep_cs().after_applying();
   m_thd->mdl_context.release_transactional_locks();
 
@@ -298,47 +293,39 @@ int Wsrep_high_priority_service::commit(const wsrep::ws_handle& ws_handle,
   thd->wsrep_cs().prepare_for_ordering(ws_handle, ws_meta, true);
   thd_proc_info(thd, "committing");
 
-  int ret= 0;
   const bool is_ordered= !ws_meta.seqno().is_undefined();
-  /* If opt_log_slave_updates is not on, applier does not write
-     anything to binlog cache and neither wsrep_before_commit()
-     nor wsrep_after_commit() we be reached from binlog code
-     path for applier. Therefore run wsrep_before_commit()
-     and wsrep_after_commit() here. wsrep_ordered_commit()
-     will be called from wsrep_ordered_commit_if_no_binlog(). */
-  if (!opt_log_slave_updates && !opt_bin_log && is_ordered)
-  {
-    if (m_thd->transaction.all.no_2pc == false)
-    {
-      ret= wsrep_before_prepare(thd, true);
-      ret= ret || wsrep_after_prepare(thd, true);
-    }
-    ret= ret || wsrep_before_commit(thd, true);
-  }
-  ret= ret || trans_commit(thd);
+  int ret= trans_commit(thd);
 
   if (ret == 0)
   {
     m_rgi->cleanup_context(thd, 0);
   }
 
-  if (ret == 0 && !opt_log_slave_updates && !opt_bin_log && is_ordered)
-  {
-    ret= wsrep_after_commit(thd, true);
-  }
-
   m_thd->mdl_context.release_transactional_locks();
 
   thd_proc_info(thd, "wsrep applier committed");
 
   if (!is_ordered)
   {
-    /* Wsrep commit was not ordered so it does not go through commit time
-       hooks and remains active. Roll it back to make cleanup happen
-       in after_applying() call. */
     m_thd->wsrep_cs().before_rollback();
     m_thd->wsrep_cs().after_rollback();
   }
+  else if (m_thd->wsrep_trx().state() == wsrep::transaction::s_executing)
+  {
+    /*
+      Wsrep commit was ordered but it did not go through commit time
+      hooks and remains active. Cycle through commit hooks to release
+      commit order and to make cleanup happen in after_applying() call.
+
+      This is a workaround for CTAS with empty result set.
+    */
+    WSREP_DEBUG("Commit not finished for applier %llu", thd->thread_id);
+    ret= ret || m_thd->wsrep_cs().before_commit() ||
+      m_thd->wsrep_cs().ordered_commit() ||
+      m_thd->wsrep_cs().after_commit();
+  }
+
+  thd->lex->sql_command= SQLCOM_END;
 
   must_exit_= check_exit_status();
   DBUG_RETURN(ret);
@@ -380,6 +367,8 @@ int Wsrep_high_priority_service::apply_toi(const wsrep::ws_meta& ws_meta,
   trans_commit(thd);
 
   thd->close_temporary_tables();
+  thd->lex->sql_command= SQLCOM_END;
+
   wsrep_set_SE_checkpoint(client_state.toi_meta().gtid());
 
   must_exit_= check_exit_status();
diff --git a/sql/wsrep_high_priority_service.h b/sql/wsrep_high_priority_service.h
index 4012ca60a3e..c483aa82d62 100644
--- a/sql/wsrep_high_priority_service.h
+++ b/sql/wsrep_high_priority_service.h
@@ -36,7 +36,7 @@ public:
   int start_transaction(const wsrep::ws_handle&,
                         const wsrep::ws_meta&);
   const wsrep::transaction& transaction() const;
-  void adopt_transaction(const wsrep::transaction&);
+  int adopt_transaction(const wsrep::transaction&);
   int apply_write_set(const wsrep::ws_meta&, const wsrep::const_buffer&) = 0;
   int append_fragment_and_commit(const wsrep::ws_handle&,
                                  const wsrep::ws_meta&,
diff --git a/sql/wsrep_storage_service.cc b/sql/wsrep_storage_service.cc
index 5a15f22ab57..e164114b733 100644
--- a/sql/wsrep_storage_service.cc
+++ b/sql/wsrep_storage_service.cc
@@ -147,39 +147,14 @@ int Wsrep_storage_service::commit(const wsrep::ws_handle& ws_handle,
   WSREP_DEBUG("Storage service commit: %llu, %lld",
               ws_meta.transaction_id().get(), ws_meta.seqno().get());
   int ret= 0;
-  const bool do_binlog_commit= (opt_log_slave_updates && wsrep_gtid_mode);
   const bool is_ordered= !ws_meta.seqno().is_undefined();
-  /*
-    Write skip event into binlog if gtid_mode is on. This is to
-    maintain gtid continuity.
-  */
-  if (do_binlog_commit && is_ordered)
-  {
-    ret= wsrep_write_skip_event(m_thd);
-  }
 
-  if (!ret && is_ordered)
+  if (is_ordered)
   {
-    ret= m_thd->wsrep_cs().prepare_for_ordering(ws_handle,
-                                                ws_meta, true);
+    ret= m_thd->wsrep_cs().prepare_for_ordering(ws_handle, ws_meta, true);
   }
 
-  if (!ret)
-  {
-    if (!do_binlog_commit && is_ordered)
-    {
-      ret= wsrep_before_commit(m_thd, true);
-    }
-    ret= ret || trans_commit(m_thd);
-    if (!do_binlog_commit && is_ordered)
-    {
-      if (opt_log_slave_updates)
-      {
-        ret= ret || wsrep_ordered_commit(m_thd, true, wsrep_apply_error());
-      }
-      ret= ret || wsrep_after_commit(m_thd, true);
-    }
-  }
+  ret= ret || trans_commit(m_thd);
 
   if (!is_ordered)
   {
diff --git a/sql/wsrep_trans_observer.h b/sql/wsrep_trans_observer.h
index 04a1224701e..46b9cf75976 100644
--- a/sql/wsrep_trans_observer.h
+++ b/sql/wsrep_trans_observer.h
@@ -1,4 +1,4 @@
-/* Copyright 2016 Codership Oy <http://www.codership.com>
+/* Copyright 2016-2019 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
@@ -32,7 +32,39 @@ class THD;
 static inline bool wsrep_is_active(THD* thd)
 {
   return (thd->wsrep_cs().state() != wsrep::client_state::s_none  &&
-	  thd->wsrep_cs().transaction().active());
+          thd->wsrep_cs().transaction().active());
+}
+
+/*
+  Return true if transaction is ordered.
+ */
+static inline bool wsrep_is_ordered(THD* thd)
+{
+  return thd->wsrep_trx().ordered();
+}
+
+/*
+  Return true if transaction has been BF aborted but has not been
+  rolled back yet.
+
+  It is required that the caller holds thd->LOCK_thd_data.
+*/
+static inline bool wsrep_must_abort(THD* thd)
+{
+  mysql_mutex_assert_owner(&thd->LOCK_thd_data);
+  return (thd->wsrep_trx().state() == wsrep::transaction::s_must_abort);
+}
+
+/*
+  Return true if transaction has not been committed.
+
+  Note that we don't require thd->LOCK_thd_data here. Calling this method
+  makes sense only from codepaths which are past ordered_commit state
+  and the wsrep transaction is immune to BF aborts at that point.
+*/
+static inline bool wsrep_not_committed(THD* thd)
+{
+  return (thd->wsrep_trx().state() != wsrep::transaction::s_committed);
 }
 
 /*
@@ -47,7 +79,7 @@ static inline bool wsrep_is_real(THD* thd, bool all)
 /*
   Check if a transaction has generated changes.
  */
-static inline bool wsrep_has_changes(THD* thd, my_bool all)
+static inline bool wsrep_has_changes(THD* thd)
 {
   return (thd->wsrep_trx().is_empty() == false);
 }
@@ -137,11 +169,42 @@ static inline int wsrep_after_row(THD* thd, bool)
 /*
   Helper method to determine whether commit time hooks
   should be run for the transaction.
+
+  Commit hooks must be run in the following cases:
+  - The transaction is local and has generated write set and is committing.
+  - The transaction has been BF aborted
+  - Is running in high priority mode and is ordered. This can be replayer,
+    applier or storage access.
  */
 static inline bool wsrep_run_commit_hook(THD* thd, bool all)
 {
-  return (wsrep_is_real(thd, all) && wsrep_is_active(thd) &&
-          (wsrep_thd_is_applying(thd) || wsrep_has_changes(thd, all)));
+  DBUG_ENTER("wsrep_run_commit_hook");
+  DBUG_PRINT("wsrep", ("Is_active: %d is_real %d has_changes %d is_applying %d "
+                       "is_ordered: %d",
+                       wsrep_is_active(thd), wsrep_is_real(thd, all),
+                       wsrep_has_changes(thd), wsrep_thd_is_applying(thd),
+                       wsrep_is_ordered(thd)));
+  /* Is MST commit or autocommit? */
+  bool ret= wsrep_is_active(thd) && wsrep_is_real(thd, all);
+  if (ret && !(wsrep_has_changes(thd) ||  /* Has generated write set */
+               /* Is high priority (replay, applier, storage) and the
+                  transaction is scheduled for commit ordering */
+               (wsrep_thd_is_applying(thd) && wsrep_is_ordered(thd))))
+  {
+    mysql_mutex_lock(&thd->LOCK_thd_data);
+    DBUG_PRINT("wsrep", ("state: %s",
+                         wsrep::to_c_string(thd->wsrep_trx().state())));
+    /* Transaction is local but has no changes, the commit hooks will
+       be skipped and the wsrep transaction is terminated in
+       wsrep_commit_empty() */
+    if (thd->wsrep_trx().state() == wsrep::transaction::s_executing)
+    {
+      ret= false;
+    }
+    mysql_mutex_unlock(&thd->LOCK_thd_data);
+  }
+  DBUG_PRINT("wsrep", ("return: %d", ret));
+  DBUG_RETURN(ret);
 }
 
 /*
@@ -154,14 +217,12 @@ static inline int wsrep_before_prepare(THD* thd, bool all)
   DBUG_ENTER("wsrep_before_prepare");
   WSREP_DEBUG("wsrep_before_prepare: %d", wsrep_is_real(thd, all));
   int ret= 0;
-  if (wsrep_run_commit_hook(thd, all))
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  if ((ret= thd->wsrep_cs().before_prepare()) == 0)
   {
-    if ((ret= thd->wsrep_cs().before_prepare()) == 0)
-    {
-      DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
-      wsrep_xid_init(&thd->wsrep_xid,
+    DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
+    wsrep_xid_init(&thd->wsrep_xid,
                      thd->wsrep_trx().ws_meta().gtid());
-    }
   }
   DBUG_RETURN(ret);
 }
@@ -175,8 +236,8 @@ static inline int wsrep_after_prepare(THD* thd, bool all)
 {
   DBUG_ENTER("wsrep_after_prepare");
   WSREP_DEBUG("wsrep_after_prepare: %d", wsrep_is_real(thd, all));
-  int ret= (wsrep_run_commit_hook(thd, all) ?
-            thd->wsrep_cs().after_prepare() : 0);
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  int ret= thd->wsrep_cs().after_prepare();
   DBUG_ASSERT(ret == 0 || thd->wsrep_cs().current_error() ||
               thd->wsrep_cs().transaction().state() == wsrep::transaction::s_must_replay);
   DBUG_RETURN(ret);
@@ -198,14 +259,12 @@ static inline int wsrep_before_commit(THD* thd, bool all)
               wsrep_is_real(thd, all),
               (long long)wsrep_thd_trx_seqno(thd));
   int ret= 0;
-  if (wsrep_run_commit_hook(thd, all))
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  if ((ret= thd->wsrep_cs().before_commit()) == 0)
   {
-    if ((ret= thd->wsrep_cs().before_commit()) == 0)
-    {
-      DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
-      wsrep_xid_init(&thd->wsrep_xid,
-                     thd->wsrep_trx().ws_meta().gtid());
-    }
+    DBUG_ASSERT(!thd->wsrep_trx().ws_meta().gtid().is_undefined());
+    wsrep_xid_init(&thd->wsrep_xid,
+                   thd->wsrep_trx().ws_meta().gtid());
   }
   DBUG_RETURN(ret);
 }
@@ -228,8 +287,8 @@ static inline int wsrep_ordered_commit(THD* thd,
 {
   DBUG_ENTER("wsrep_ordered_commit");
   WSREP_DEBUG("wsrep_ordered_commit: %d", wsrep_is_real(thd, all));
-  DBUG_RETURN(wsrep_run_commit_hook(thd, all) ?
-              thd->wsrep_cs().ordered_commit() : 0);
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  DBUG_RETURN(thd->wsrep_cs().ordered_commit());
 }
 
 /*
@@ -244,14 +303,12 @@ static inline int wsrep_after_commit(THD* thd, bool all)
               wsrep_is_real(thd, all),
               wsrep_is_active(thd),
               (long long)wsrep_thd_trx_seqno(thd),
-              wsrep_has_changes(thd, all));
-  if (wsrep_run_commit_hook(thd, all))
-  {
-    DBUG_RETURN((wsrep_ordered_commit_if_no_binlog(thd, all) ||
-                 (thd->wsrep_xid.null(),
-                  thd->wsrep_cs().after_commit())));
-  }
-  DBUG_RETURN(0);
+              wsrep_has_changes(thd));
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  DBUG_RETURN((thd->wsrep_trx().state() == wsrep::transaction::s_committing
+               ? thd->wsrep_cs().ordered_commit() : 0) ||
+              (thd->wsrep_xid.null(),
+               thd->wsrep_cs().after_commit()));
 }
 
 /*
@@ -415,11 +472,25 @@ static inline void wsrep_commit_empty(THD* thd, bool all)
       thd->wsrep_trx().active() &&
       thd->wsrep_trx().state() != wsrep::transaction::s_committed)
   {
+    /* @todo CTAS with STATEMENT binlog format and empty result set
+       seems to be committing empty. Figure out why and try to fix
+       elsewhere. */
+    DBUG_ASSERT(!wsrep_has_changes(thd) ||
+                (thd->lex->sql_command == SQLCOM_CREATE_TABLE &&
+                 !thd->is_current_stmt_binlog_format_row()));
     bool have_error= wsrep_current_error(thd);
     int ret= wsrep_before_rollback(thd, all) ||
       wsrep_after_rollback(thd, all) ||
       wsrep_after_statement(thd);
-    DBUG_ASSERT(have_error || !wsrep_current_error(thd));
+    /* The committing transaction was empty but it held some locks and
+       got BF aborted. As there were no certified changes in the
+       data, we ignore the deadlock error and rely on error reporting
+       by storage engine/server. */
+    if (!ret && !have_error && wsrep_current_error(thd))
+    {
+      DBUG_ASSERT(wsrep_current_error(thd) == wsrep::e_deadlock_error);
+      thd->wsrep_cs().reset_error();
+    }
     if (ret)
     {
       WSREP_DEBUG("wsrep_commit_empty failed: %d", wsrep_current_error(thd));