1 files changed, 513 insertions, 0 deletions

diff --git a/sql/wsrep_trans_observer.h b/sql/wsrep_trans_observer.h
new file mode 100644
index 00000000000..e6901f15ca7
--- /dev/null
+++ b/sql/wsrep_trans_observer.h
@@ -0,0 +1,513 @@
+/* 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
+   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 */
+
+#ifndef WSREP_TRANS_OBSERVER_H
+#define WSREP_TRANS_OBSERVER_H
+
+#include "my_global.h"
+#include "mysql/service_wsrep.h"
+#include "wsrep_applier.h" /* wsrep_apply_error */
+#include "wsrep_xid.h"
+#include "wsrep_thd.h"
+#include "wsrep_binlog.h" /* register/deregister group commit */
+#include "my_dbug.h"
+
+class THD;
+
+/*
+   Return true if THD has active wsrep transaction.
+ */
+static inline bool wsrep_is_active(THD* thd)
+{
+  return (thd->wsrep_cs().state() != wsrep::client_state::s_none  &&
+          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 the transaction must be replayed.
+ */
+static inline bool wsrep_must_replay(THD* thd)
+{
+  return (thd->wsrep_trx().state() == wsrep::transaction::s_must_replay);
+}
+/*
+  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);
+}
+
+/*
+  Return true if THD is either committing a transaction or statement
+  is autocommit.
+ */
+static inline bool wsrep_is_real(THD* thd, bool all)
+{
+  return (all || thd->transaction.all.ha_list == 0);
+}
+
+/*
+  Check if a transaction has generated changes.
+ */
+static inline bool wsrep_has_changes(THD* thd)
+{
+  return (thd->wsrep_trx().is_empty() == false);
+}
+
+/*
+  Check if an active transaction has been BF aborted.
+ */
+static inline bool wsrep_is_bf_aborted(THD* thd)
+{
+  return (thd->wsrep_trx().active() && thd->wsrep_trx().bf_aborted());
+}
+
+static inline int wsrep_check_pk(THD* thd)
+{
+  if (!wsrep_certify_nonPK)
+  {
+    for (TABLE* table= thd->open_tables; table != NULL; table= table->next)
+    {
+      if (table->key_info == NULL || table->s->primary_key == MAX_KEY)
+      {
+        WSREP_DEBUG("No primary key found for table %s.%s",
+                    table->s->db.str, table->s->table_name.str);
+        wsrep_override_error(thd, ER_LOCK_DEADLOCK);
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+static inline bool wsrep_streaming_enabled(THD* thd)
+{
+  return (thd->wsrep_sr().fragment_size() > 0);
+}
+
+/*
+  Return number of fragments succesfully certified for the
+  current statement.
+ */
+static inline size_t wsrep_fragments_certified_for_stmt(THD* thd)
+{
+    return thd->wsrep_trx().fragments_certified_for_statement();
+}
+
+static inline int wsrep_start_transaction(THD* thd, wsrep_trx_id_t trx_id)
+{
+  return (thd->wsrep_cs().state() != wsrep::client_state::s_none  ?
+          thd->wsrep_cs().start_transaction(wsrep::transaction_id(trx_id)) :
+          0);
+}
+
+/**/
+static inline int wsrep_start_trx_if_not_started(THD* thd)
+{
+  int ret= 0;
+  DBUG_ASSERT(thd->wsrep_next_trx_id() != WSREP_UNDEFINED_TRX_ID);
+  DBUG_ASSERT(thd->wsrep_cs().mode() == Wsrep_client_state::m_local);
+  if (thd->wsrep_trx().active() == false)
+  {
+    ret= wsrep_start_transaction(thd, thd->wsrep_next_trx_id());
+  }
+  return ret;
+}
+
+/*
+  Called after each row operation.
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_after_row(THD* thd, bool)
+{
+  if (thd->wsrep_cs().state() != wsrep::client_state::s_none  &&
+      wsrep_thd_is_local(thd))
+  {
+    if (wsrep_check_pk(thd))
+    {
+      return 1;
+    }
+    else if (wsrep_streaming_enabled(thd))
+    {
+      return thd->wsrep_cs().after_row();
+    }
+  }
+  return 0;
+}
+
+/*
+  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)
+{
+  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);
+}
+
+/*
+  Called before the transaction is prepared.
+
+  Return zero on succes, non-zero on failure.
+ */
+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;
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  if ((ret= thd->wsrep_cs().before_prepare()) == 0)
+  {
+    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);
+}
+
+/*
+  Called after the transaction has been prepared.
+
+  Return zero on succes, non-zero on failure.
+ */
+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));
+  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);
+}
+
+/*
+  Called before the transaction is committed.
+
+  This function must be called from both client and
+  applier contexts before commit.
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_before_commit(THD* thd, bool all)
+{
+  DBUG_ENTER("wsrep_before_commit");
+  WSREP_DEBUG("wsrep_before_commit: %d, %lld",
+              wsrep_is_real(thd, all),
+              (long long)wsrep_thd_trx_seqno(thd));
+  int ret= 0;
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  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());
+    wsrep_register_for_group_commit(thd);
+  }
+  DBUG_RETURN(ret);
+}
+
+/*
+  Called after the transaction has been ordered for commit.
+
+  This function must be called from both client and
+  applier contexts after the commit has been ordered.
+
+  @param thd Pointer to THD
+  @param all 
+  @param err Error buffer in case of applying error
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_ordered_commit(THD* thd,
+                                      bool all,
+                                      const wsrep_apply_error&)
+{
+  DBUG_ENTER("wsrep_ordered_commit");
+  WSREP_DEBUG("wsrep_ordered_commit: %d", wsrep_is_real(thd, all));
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  DBUG_RETURN(thd->wsrep_cs().ordered_commit());
+}
+
+/*
+  Called after the transaction has been committed.
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_after_commit(THD* thd, bool all)
+{
+  DBUG_ENTER("wsrep_after_commit");
+  WSREP_DEBUG("wsrep_after_commit: %d, %d, %lld, %d",
+              wsrep_is_real(thd, all),
+              wsrep_is_active(thd),
+              (long long)wsrep_thd_trx_seqno(thd),
+              wsrep_has_changes(thd));
+  DBUG_ASSERT(wsrep_run_commit_hook(thd, all));
+  int ret= 0;
+  if (thd->wsrep_trx().state() == wsrep::transaction::s_committing)
+  {
+    ret= thd->wsrep_cs().ordered_commit();
+  }
+  wsrep_unregister_from_group_commit(thd);
+  thd->wsrep_xid.null();
+  DBUG_RETURN(ret || thd->wsrep_cs().after_commit());
+}
+
+/*
+  Called before the transaction is rolled back.
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_before_rollback(THD* thd, bool all)
+{
+  DBUG_ENTER("wsrep_before_rollback");
+  int ret= 0;
+  if (wsrep_is_active(thd))
+  {
+    if (!all && thd->in_active_multi_stmt_transaction() &&
+        thd->wsrep_trx().is_streaming() &&
+        !wsrep_stmt_rollback_is_safe(thd))
+    {
+      /* Non-safe statement rollback during SR multi statement
+         transasction. Self abort the transaction, the actual rollback
+         and error handling will be done in after statement phase. */
+      wsrep_thd_self_abort(thd);
+      ret= 0;
+    }
+    else if (wsrep_is_real(thd, all) &&
+             thd->wsrep_trx().state() != wsrep::transaction::s_aborted)
+    {
+      /* Real transaction rolling back and wsrep abort not completed
+         yet */
+      /* Reset XID so that it does not trigger writing serialization
+         history in InnoDB. This needs to be avoided because rollback
+         may happen out of order and replay may follow. */
+      thd->wsrep_xid.null();
+      ret= thd->wsrep_cs().before_rollback();
+    }
+  }
+  DBUG_RETURN(ret);
+}
+
+/*
+  Called after the transaction has been rolled back.
+
+  Return zero on succes, non-zero on failure.
+ */
+static inline int wsrep_after_rollback(THD* thd, bool all)
+{
+  DBUG_ENTER("wsrep_after_rollback");
+  DBUG_RETURN((wsrep_is_real(thd, all) && wsrep_is_active(thd) &&
+               thd->wsrep_cs().transaction().state() !=
+               wsrep::transaction::s_aborted) ?
+              thd->wsrep_cs().after_rollback() : 0);
+}
+
+static inline int wsrep_before_statement(THD* thd)
+{
+  return (thd->wsrep_cs().state() != wsrep::client_state::s_none ?
+	  thd->wsrep_cs().before_statement() : 0);
+}
+
+static inline
+int wsrep_after_statement(THD* thd)
+{
+  DBUG_ENTER("wsrep_after_statement");
+  DBUG_RETURN(thd->wsrep_cs().state() != wsrep::client_state::s_none ?
+              thd->wsrep_cs().after_statement() : 0);
+}
+
+static inline void wsrep_after_apply(THD* thd)
+{
+  DBUG_ASSERT(wsrep_thd_is_applying(thd));
+  WSREP_DEBUG("wsrep_after_apply %lld", thd->thread_id);
+  thd->wsrep_cs().after_applying();
+}
+
+static inline void wsrep_open(THD* thd)
+{
+  DBUG_ENTER("wsrep_open");
+  if (wsrep_on(thd))
+  {
+    thd->wsrep_cs().open(wsrep::client_id(thd->thread_id));
+    thd->wsrep_cs().debug_log_level(wsrep_debug);
+    if (!thd->wsrep_applier && thd->variables.wsrep_trx_fragment_size)
+    {
+      thd->wsrep_cs().enable_streaming(
+        wsrep_fragment_unit(thd->variables.wsrep_trx_fragment_unit),
+        size_t(thd->variables.wsrep_trx_fragment_size));
+    }
+  }
+  DBUG_VOID_RETURN;
+}
+
+static inline void wsrep_close(THD* thd)
+{
+  DBUG_ENTER("wsrep_close");
+  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
+  {
+    thd->wsrep_cs().close();
+  }
+  DBUG_VOID_RETURN;
+}
+
+static inline int wsrep_before_command(THD* thd)
+{
+  return (thd->wsrep_cs().state() != wsrep::client_state::s_none ?
+	  thd->wsrep_cs().before_command() : 0);
+}
+/*
+  Called after each command.
+
+  Return zero on success, non-zero on failure.
+*/
+static inline void wsrep_after_command_before_result(THD* thd)
+{
+  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
+  {
+    thd->wsrep_cs().after_command_before_result();
+  }
+}
+
+static inline void wsrep_after_command_after_result(THD* thd)
+{
+  if (thd->wsrep_cs().state() != wsrep::client_state::s_none)
+  {
+    thd->wsrep_cs().after_command_after_result();
+  }
+}
+
+static inline void wsrep_after_command_ignore_result(THD* thd)
+{
+  wsrep_after_command_before_result(thd);
+  DBUG_ASSERT(!thd->wsrep_cs().current_error());
+  wsrep_after_command_after_result(thd);
+}
+
+static inline enum wsrep::client_error wsrep_current_error(THD* thd)
+{
+  return thd->wsrep_cs().current_error();
+}
+
+static inline enum wsrep::provider::status
+wsrep_current_error_status(THD* thd)
+{
+  return thd->wsrep_cs().current_error_status();
+}
+
+
+/*
+  Commit an empty transaction.
+
+  If the transaction is real and the wsrep transaction is still active,
+  the transaction did not generate any rows or keys and is committed
+  as empty. Here the wsrep transaction is rolled back and after statement
+  step is performed to leave the wsrep transaction in the state as it
+  never existed.
+*/
+static inline void wsrep_commit_empty(THD* thd, bool all)
+{
+  DBUG_ENTER("wsrep_commit_empty");
+  WSREP_DEBUG("wsrep_commit_empty(%llu)", thd->thread_id);
+  if (wsrep_is_real(thd, all) &&
+      wsrep_thd_is_local(thd) &&
+      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);
+    /* 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));
+    }
+  }
+  DBUG_VOID_RETURN;
+}
+
+#endif /* WSREP_TRANS_OBSERVER */