MDEV-25594: Improve debug checks

trx_t::will_lock: Changed the type to bool.

trx_t::is_autocommit_non_locking(): Replaces
trx_is_autocommit_non_locking().

trx_is_ac_nl_ro(): Remove (replaced with equivalent assertion expressions).

assert_trx_nonlocking_or_in_list(): Remove.
Replaced with at least as strict checks in each place.

check_trx_state(): Moved to a static function; partially replaced with
individual debug assertions implementing equivalent or stricter checks.

storage/innobase/handler/ha_innodb.cc

@@ -4123,7 +4123,7 @@ innobase_commit_low(
 	if (trx_is_started(trx)) {
 		trx_commit_for_mysql(trx);
 	} else {
-		trx->will_lock = 0;
+		trx->will_lock = false;
 #ifdef WITH_WSREP
 		trx->wsrep = false;
 #endif /* WITH_WSREP */
@@ -7610,7 +7610,7 @@ ha_innobase::write_row(
 	ut_a(m_prebuilt->trx == trx);
 
 	if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	ins_mode_t	vers_set_fields;
@@ -8369,7 +8369,7 @@ ha_innobase::update_row(
 		ib_senderrf(ha_thd(), IB_LOG_LEVEL_WARN, ER_READ_ONLY_MODE);
 		DBUG_RETURN(HA_ERR_TABLE_READONLY);
 	} else if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	if (m_upd_buf == NULL) {
@@ -8540,7 +8540,7 @@ ha_innobase::delete_row(
 		ib_senderrf(ha_thd(), IB_LOG_LEVEL_WARN, ER_READ_ONLY_MODE);
 		DBUG_RETURN(HA_ERR_TABLE_READONLY);
 	} else if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	if (!m_prebuilt->upd_node) {
@@ -9377,7 +9377,7 @@ ha_innobase::ft_init()
 	them as regular read only transactions for now. */
 
 	if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	DBUG_RETURN(rnd_init(false));
@@ -9443,7 +9443,7 @@ ha_innobase::ft_init_ext(
 	them as regular read only transactions for now. */
 
 	if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	dict_table_t*	ft_table = m_prebuilt->table;
@@ -12972,7 +12972,7 @@ create_table_info_t::allocate_trx()
 {
 	m_trx = innobase_trx_allocate(m_thd);
 
-	m_trx->will_lock++;
+	m_trx->will_lock = true;
 	m_trx->ddl = true;
 }
 
@@ -13296,13 +13296,7 @@ inline int ha_innobase::delete_table(const char* name, enum_sql_command sqlcom)
 
 	ut_a(name_len < 1000);
 
-	/* Either the transaction is already flagged as a locking transaction
-	or it hasn't been started yet. */
-
-	ut_a(!trx_is_started(trx) || trx->will_lock > 0);
-
-	/* We are doing a DDL operation. */
-	++trx->will_lock;
+	trx->will_lock = true;
 
 	/* Drop the table in InnoDB */
 
@@ -13481,14 +13475,7 @@ innobase_drop_database(
 #endif /* _WIN32 */
 
 	trx_t*	trx = innobase_trx_allocate(thd);
-
-	/* Either the transaction is already flagged as a locking transaction
-	or it hasn't been started yet. */
-
-	ut_a(!trx_is_started(trx) || trx->will_lock > 0);
-
-	/* We are doing a DDL operation. */
-	++trx->will_lock;
+	trx->will_lock = true;
 
 	ulint	dummy;
 
@@ -13532,7 +13519,7 @@ inline dberr_t innobase_rename_table(trx_t *trx, const char *from,
 	DEBUG_SYNC_C("innodb_rename_table_ready");
 
 	trx_start_if_not_started(trx, true);
-	ut_ad(trx->will_lock > 0);
+	ut_ad(trx->will_lock);
 
 	if (commit) {
 		/* Serialize data dictionary operations with dictionary mutex:
@@ -13642,8 +13629,7 @@ int ha_innobase::truncate()
 		heap, ib_table->name.m_name, ib_table->id);
 	const char* name = mem_heap_strdup(heap, ib_table->name.m_name);
 	trx_t*	trx = innobase_trx_allocate(m_user_thd);
-
-	++trx->will_lock;
+	trx->will_lock = true;
 	trx_set_dict_operation(trx, TRX_DICT_OP_TABLE);
 	row_mysql_lock_data_dictionary(trx);
 	dict_stats_wait_bg_to_stop_using_table(ib_table, trx);
@@ -13728,9 +13714,7 @@ ha_innobase::rename_table(
 	}
 
 	trx_t*	trx = innobase_trx_allocate(thd);
-
-	/* We are doing a DDL operation. */
-	++trx->will_lock;
+	trx->will_lock = true;
 	trx_set_dict_operation(trx, TRX_DICT_OP_INDEX);
 
 	dberr_t	error = innobase_rename_table(trx, from, to, true);
@@ -15602,7 +15586,7 @@ ha_innobase::start_stmt(
 	innobase_register_trx(ht, thd, trx);
 
 	if (!trx_is_started(trx)) {
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	DBUG_RETURN(0);
@@ -15828,7 +15812,7 @@ ha_innobase::external_lock(
 		    && (m_prebuilt->select_lock_type != LOCK_NONE
 			|| m_prebuilt->stored_select_lock_type != LOCK_NONE)) {
 
-			++trx->will_lock;
+			trx->will_lock = true;
 		}
 
 		DBUG_RETURN(0);
@@ -15867,7 +15851,7 @@ ha_innobase::external_lock(
 	    && (m_prebuilt->select_lock_type != LOCK_NONE
 		|| m_prebuilt->stored_select_lock_type != LOCK_NONE)) {
 
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	DBUG_RETURN(0);
@@ -16540,7 +16524,7 @@ ha_innobase::store_lock(
 	    && (m_prebuilt->select_lock_type != LOCK_NONE
 	        || m_prebuilt->stored_select_lock_type != LOCK_NONE)) {
 
-		++trx->will_lock;
+		trx->will_lock = true;
 	}
 
 	return(to);

storage/innobase/handler/handler0alter.cc

@@ -2352,7 +2352,7 @@ ha_innobase::check_if_supported_inplace_alter(
 		}
 	}
 
-	m_prebuilt->trx->will_lock++;
+	m_prebuilt->trx->will_lock = true;
 
 	/* When changing a NULL column to NOT NULL and specifying a
 	DEFAULT value, ensure that the DEFAULT expression is a constant.
@@ -11458,7 +11458,6 @@ ha_innobase::commit_inplace_alter_table(
 				m_prebuilt = ctx->prebuilt;
 			}
 			trx_start_if_not_started(user_trx, true);
-			user_trx->will_lock++;
 			m_prebuilt->trx = user_trx;
 		}
 		DBUG_INJECT_CRASH("ib_commit_inplace_crash",

storage/innobase/include/trx0i_s.h

 /*****************************************************************************
 
 Copyright (c) 2007, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2020, MariaDB Corporation.
+Copyright (c) 2017, 2021, MariaDB Corporation.
 
 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
@@ -151,7 +151,7 @@ struct i_s_trx_row_t {
 	bool		trx_is_read_only;
 					/*!< trx_t::read_only */
 	bool		trx_is_autocommit_non_locking;
-					/*!< trx_is_autocommit_non_locking(trx)
+					/*!< trx:t::is_autocommit_non_locking()
 					*/
 };
 

storage/innobase/include/trx0sys.h

@@ -513,7 +513,7 @@ class rw_trx_hash_t
   static void validate_element(trx_t *trx)
   {
     ut_ad(!trx->read_only || !trx->rsegs.m_redo.rseg);
-    ut_ad(!trx_is_autocommit_non_locking(trx));
+    ut_ad(!trx->is_autocommit_non_locking());
     /* trx->state can be anything except TRX_STATE_NOT_STARTED */
     mutex_enter(&trx->mutex);
     ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE) ||

storage/innobase/include/trx0trx.h

@@ -393,64 +393,6 @@ from innodb_lock_wait_timeout via trx_t::mysql_thd.
 	 ? thd_lock_wait_timeout((t)->mysql_thd)			\
 	 : 0)
 
-/**
-Determine if the transaction is a non-locking autocommit select
-(implied read-only).
-@param t transaction
-@return true if non-locking autocommit select transaction. */
-#define trx_is_autocommit_non_locking(t)				\
-((t)->auto_commit && (t)->will_lock == 0)
-
-/**
-Determine if the transaction is a non-locking autocommit select
-with an explicit check for the read-only status.
-@param t transaction
-@return true if non-locking autocommit read-only transaction. */
-#define trx_is_ac_nl_ro(t)						\
-((t)->read_only && trx_is_autocommit_non_locking((t)))
-
-/**
-Check transaction state */
-#define check_trx_state(t) do {						\
-	ut_ad(!trx_is_autocommit_non_locking((t)));			\
-	switch ((t)->state) {						\
-	case TRX_STATE_PREPARED:					\
-	case TRX_STATE_PREPARED_RECOVERED:				\
-	case TRX_STATE_ACTIVE:						\
-	case TRX_STATE_COMMITTED_IN_MEMORY:				\
-		continue;						\
-	case TRX_STATE_NOT_STARTED:					\
-		break;							\
-	}								\
-	ut_error;							\
-} while (0)
-
-#ifdef UNIV_DEBUG
-/*******************************************************************//**
-Assert that an autocommit non-locking select cannot be in the
-rw_trx_hash and that it is a read-only transaction.
-The transaction must have mysql_thd assigned. */
-# define assert_trx_nonlocking_or_in_list(t)				\
-	do {								\
-		if (trx_is_autocommit_non_locking(t)) {			\
-			trx_state_t	t_state = (t)->state;		\
-			ut_ad((t)->read_only);				\
-			ut_ad(!(t)->is_recovered);			\
-			ut_ad((t)->mysql_thd);				\
-			ut_ad(t_state == TRX_STATE_NOT_STARTED		\
-			      || t_state == TRX_STATE_ACTIVE);		\
-		} else {						\
-			check_trx_state(t);				\
-		}							\
-	} while (0)
-#else /* UNIV_DEBUG */
-/*******************************************************************//**
-Assert that an autocommit non-locking slect cannot be in the
-rw_trx_hash and that it is a read-only transaction.
-The transaction must have mysql_thd assigned. */
-# define assert_trx_nonlocking_or_in_list(trx) ((void)0)
-#endif /* UNIV_DEBUG */
-
 typedef std::vector<ib_lock_t*, ut_allocator<ib_lock_t*> >	lock_list;
 
 /*******************************************************************//**
@@ -947,16 +889,15 @@ struct trx_t : ilist_node<> {
 	/*------------------------------*/
 	bool		read_only;	/*!< true if transaction is flagged
 					as a READ-ONLY transaction.
-					if auto_commit && will_lock == 0
+					if auto_commit && !will_lock
 					then it will be handled as a
 					AC-NL-RO-SELECT (Auto Commit Non-Locking
 					Read Only Select). A read only
 					transaction will not be assigned an
 					UNDO log. */
 	bool		auto_commit;	/*!< true if it is an autocommit */
-	ib_uint32_t	will_lock;	/*!< Will acquire some locks. Increment
-					each time we determine that a lock will
-					be acquired by the MySQL layer. */
+	bool		will_lock;	/*!< set to inform trx_start_low() that
+					the transaction may acquire locks */
 	/*------------------------------*/
 	fts_trx_t*	fts_trx;	/*!< FTS information, or NULL if
 					transaction hasn't modified tables
@@ -1103,11 +1044,13 @@ struct trx_t : ilist_node<> {
     ut_ad(dict_operation == TRX_DICT_OP_NONE);
   }
 
+  /** @return whether this is a non-locking autocommit transaction */
+  bool is_autocommit_non_locking() const { return auto_commit && !will_lock; }
 
 private:
-	/** Assign a rollback segment for modifying temporary tables.
-	@return the assigned rollback segment */
-	trx_rseg_t* assign_temp_rseg();
+  /** Assign a rollback segment for modifying temporary tables.
+  @return the assigned rollback segment */
+  trx_rseg_t *assign_temp_rseg();
 };
 
 /**

storage/innobase/include/trx0trx.ic

 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2019, MariaDB Corporation.
+Copyright (c) 2016, 2021, MariaDB Corporation.
 
 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
@@ -49,11 +49,15 @@ trx_state_eq(
 	case TRX_STATE_PREPARED:
 	case TRX_STATE_PREPARED_RECOVERED:
 	case TRX_STATE_COMMITTED_IN_MEMORY:
-		ut_ad(!trx_is_autocommit_non_locking(trx));
+		ut_ad(!trx->is_autocommit_non_locking());
 		return(trx->state == state);
 
 	case TRX_STATE_ACTIVE:
-		assert_trx_nonlocking_or_in_list(trx);
+		if (trx->is_autocommit_non_locking()) {
+			ut_ad(!trx->is_recovered);
+			ut_ad(trx->read_only);
+			ut_ad(trx->mysql_thd);
+		}
 		return(state == trx->state);
 
 	case TRX_STATE_NOT_STARTED:

storage/innobase/lock/lock0lock.cc

@@ -1240,6 +1240,19 @@ wsrep_print_wait_locks(
 }
 #endif /* WITH_WSREP */
 
+#ifdef UNIV_DEBUG
+/** Check transaction state */
+static void check_trx_state(const trx_t *trx)
+{
+  ut_ad(!trx->auto_commit || trx->will_lock);
+  const auto state= trx->state;
+  ut_ad(state == TRX_STATE_ACTIVE ||
+        state == TRX_STATE_PREPARED_RECOVERED ||
+        state == TRX_STATE_PREPARED ||
+        state == TRX_STATE_COMMITTED_IN_MEMORY);
+}
+#endif
+
 /** Create a new record lock and inserts it to the lock queue,
 without checking for deadlocks or conflicts.
 @param[in]	type_mode	lock mode and wait flag; type will be replaced
@@ -3346,8 +3359,8 @@ lock_table_create(
 	ut_ad(table && trx);
 	ut_ad(lock_mutex_own());
 	ut_ad(trx_mutex_own(trx));
-
-	check_trx_state(trx);
+	ut_ad(trx->is_recovered || trx->state == TRX_STATE_ACTIVE);
+	ut_ad(!trx->auto_commit || trx->will_lock);
 
 	if ((type_mode & LOCK_MODE_MASK) == LOCK_AUTO_INC) {
 		++table->n_waiting_or_granted_auto_inc_locks;
@@ -4708,7 +4721,8 @@ lock_rec_queue_validate(
 			ut_ad(!index || lock->index == index);
 
 			trx_mutex_enter(lock->trx);
-			ut_ad(!trx_is_ac_nl_ro(lock->trx));
+			ut_ad(!lock->trx->read_only
+			      || !lock->trx->is_autocommit_non_locking());
 			ut_ad(trx_state_eq(lock->trx,
 					   TRX_STATE_COMMITTED_IN_MEMORY)
 			      || !lock_get_wait(lock)
@@ -4794,8 +4808,8 @@ lock_rec_queue_validate(
 	for (lock = lock_rec_get_first(&lock_sys.rec_hash, block, heap_no);
 	     lock != NULL;
 	     lock = lock_rec_get_next_const(heap_no, lock)) {
-
-		ut_ad(!trx_is_ac_nl_ro(lock->trx));
+		ut_ad(!lock->trx->read_only
+		      || !lock->trx->is_autocommit_non_locking());
 		ut_ad(!page_rec_is_metadata(rec));
 
 		if (index) {
@@ -4881,7 +4895,8 @@ lock_rec_validate_page(
 		}
 	}
 
-	ut_ad(!trx_is_ac_nl_ro(lock->trx));
+	ut_ad(!lock->trx->read_only
+	      || !lock->trx->is_autocommit_non_locking());
 
 	/* Only validate the record queues when this thread is not
 	holding a space->latch. */
@@ -4946,7 +4961,8 @@ lock_rec_validate(
 	     lock != NULL;
 	     lock = static_cast<const lock_t*>(HASH_GET_NEXT(hash, lock))) {
 
-		ut_ad(!trx_is_ac_nl_ro(lock->trx));
+		ut_ad(!lock->trx->read_only
+		      || !lock->trx->is_autocommit_non_locking());
 		ut_ad(lock_get_type(lock) == LOCK_REC);
 
 		page_id_t current(lock->un_member.rec_lock.page_id);
@@ -6514,7 +6530,8 @@ DeadlockChecker::search()
 
 	ut_ad(m_start != NULL);
 	ut_ad(m_wait_lock != NULL);
-	check_trx_state(m_wait_lock->trx);
+	ut_ad(!m_wait_lock->trx->auto_commit || m_wait_lock->trx->will_lock);
+	ut_d(check_trx_state(m_wait_lock->trx));
 	ut_ad(m_mark_start <= s_lock_mark_counter);
 
 	/* Look at the locks ahead of wait_lock in the lock queue. */
@@ -6679,7 +6696,8 @@ DeadlockChecker::check_and_resolve(const lock_t* lock, trx_t* trx)
 {
 	ut_ad(lock_mutex_own());
 	ut_ad(trx_mutex_own(trx));
-	check_trx_state(trx);
+	ut_ad(trx->state == TRX_STATE_ACTIVE);
+	ut_ad(!trx->auto_commit || trx->will_lock);
 	ut_ad(!srv_read_only_mode);
 
 	if (!innobase_deadlock_detect) {

storage/innobase/read/read0read.cc

 /*****************************************************************************
 
 Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2018, 2019, MariaDB Corporation.
+Copyright (c) 2018, 2021, MariaDB Corporation.
 
 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
@@ -221,7 +221,7 @@ void ReadView::open(trx_t *trx)
   else if (likely(!srv_read_only_mode))
   {
     m_creator_trx_id= trx->id;
-    if (trx_is_autocommit_non_locking(trx) && empty() &&
+    if (trx->is_autocommit_non_locking() && empty() &&
         low_limit_id() == trx_sys.get_max_trx_id())
       m_open.store(true, std::memory_order_relaxed);
     else

storage/innobase/trx/trx0i_s.cc

@@ -518,7 +518,7 @@ fill_trx_row(
 
 	row->trx_is_read_only = trx->read_only;
 
-	row->trx_is_autocommit_non_locking = trx_is_autocommit_non_locking(trx);
+	row->trx_is_autocommit_non_locking = trx->is_autocommit_non_locking();
 
 	return(TRUE);
 }
@@ -1175,7 +1175,24 @@ static void fetch_data_into_cache_low(trx_i_s_cache_t *cache, const trx_t *trx)
 {
   i_s_locks_row_t *requested_lock_row;
 
-  assert_trx_nonlocking_or_in_list(trx);
+#ifdef UNIV_DEBUG
+  {
+    const auto state= trx->state;
+
+    if (trx->is_autocommit_non_locking())
+    {
+      ut_ad(trx->read_only);
+      ut_ad(!trx->is_recovered);
+      ut_ad(trx->mysql_thd);
+      ut_ad(state == TRX_STATE_NOT_STARTED || state == TRX_STATE_ACTIVE);
+    }
+    else
+      ut_ad(state == TRX_STATE_ACTIVE ||
+            state == TRX_STATE_PREPARED ||
+            state == TRX_STATE_PREPARED_RECOVERED ||
+            state == TRX_STATE_COMMITTED_IN_MEMORY);
+  }
+#endif /* UNIV_DEBUG */
 
   if (add_trx_relevant_locks_to_cache(cache, trx, &requested_lock_row))
   {

storage/innobase/trx/trx0roll.cc

 /*****************************************************************************
 
 Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2016, 2020, MariaDB Corporation.
+Copyright (c) 2016, 2021, MariaDB Corporation.
 
 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
@@ -101,10 +101,21 @@ inline void trx_t::rollback_low(trx_savept_t *savept)
   roll_node_t *roll_node= roll_node_create(heap);
   roll_node->savept= savept;
 
-  if (savept)
-    check_trx_state(this);
-  else
-    assert_trx_nonlocking_or_in_list(this);
+  ut_ad(!in_rollback);
+#ifdef UNIV_DEBUG
+  {
+    const auto s= state;
+    ut_ad(s == TRX_STATE_ACTIVE ||
+          s == TRX_STATE_PREPARED ||
+          s == TRX_STATE_PREPARED_RECOVERED);
+    if (savept)
+    {
+      ut_ad(s == TRX_STATE_ACTIVE);
+      ut_ad(mysql_thd);
+      ut_ad(!is_recovered);
+    }
+  }
+#endif
 
   error_state = DB_SUCCESS;
 
@@ -203,7 +214,7 @@ dberr_t trx_rollback_for_mysql(trx_t* trx)
 
 	switch (trx->state) {
 	case TRX_STATE_NOT_STARTED:
-		trx->will_lock = 0;
+		trx->will_lock = false;
 		ut_ad(trx->mysql_thd);
 #ifdef WITH_WSREP
 		trx->wsrep= false;
@@ -213,12 +224,13 @@ dberr_t trx_rollback_for_mysql(trx_t* trx)
 
 	case TRX_STATE_ACTIVE:
 		ut_ad(trx->mysql_thd);
-		assert_trx_nonlocking_or_in_list(trx);
+		ut_ad(!trx->is_recovered);
+		ut_ad(!trx->is_autocommit_non_locking() || trx->read_only);
 		return(trx_rollback_for_mysql_low(trx));
 
 	case TRX_STATE_PREPARED:
 	case TRX_STATE_PREPARED_RECOVERED:
-		ut_ad(!trx_is_autocommit_non_locking(trx));
+		ut_ad(!trx->is_autocommit_non_locking());
 		if (trx->rsegs.m_redo.undo || trx->rsegs.m_redo.old_insert) {
 			/* The XA ROLLBACK of a XA PREPARE transaction
 			will consist of multiple mini-transactions.
@@ -265,7 +277,7 @@ dberr_t trx_rollback_for_mysql(trx_t* trx)
 		return(trx_rollback_for_mysql_low(trx));
 
 	case TRX_STATE_COMMITTED_IN_MEMORY:
-		check_trx_state(trx);
+		ut_ad(!trx->is_autocommit_non_locking());
 		break;
 	}
 
@@ -294,7 +306,9 @@ trx_rollback_last_sql_stat_for_mysql(
 		return(DB_SUCCESS);
 
 	case TRX_STATE_ACTIVE:
-		assert_trx_nonlocking_or_in_list(trx);
+		ut_ad(trx->mysql_thd);
+		ut_ad(!trx->is_recovered);
+		ut_ad(!trx->is_autocommit_non_locking() || trx->read_only);
 
 		trx->op_info = "rollback of SQL statement";
 

storage/innobase/trx/trx0trx.cc

@@ -137,7 +137,7 @@ trx_init(
 
 	trx->auto_commit = false;
 
-	trx->will_lock = 0;
+	trx->will_lock = false;
 
 	trx->ddl = false;
 
@@ -353,7 +353,7 @@ trx_t *trx_create()
 	ib_alloc_t*	alloc;
 
 	/* We just got trx from pool, it should be non locking */
-	ut_ad(trx->will_lock == 0);
+	ut_ad(!trx->will_lock);
 	ut_ad(!trx->rw_trx_hash_pins);
 
 	DBUG_LOG("trx", "Create: " << trx);
@@ -564,7 +564,7 @@ void trx_disconnect_prepared(trx_t *trx)
   trx->is_recovered= true;
   trx->mysql_thd= NULL;
   /* todo/fixme: suggest to do it at innodb prepare */
-  trx->will_lock= 0;
+  trx->will_lock= false;
   trx_sys.rw_trx_hash.put_pins(trx);
 }
 
@@ -911,11 +911,10 @@ static trx_rseg_t* trx_assign_rseg_low()
 
 /** Assign a rollback segment for modifying temporary tables.
 @return the assigned rollback segment */
-trx_rseg_t*
-trx_t::assign_temp_rseg()
+trx_rseg_t *trx_t::assign_temp_rseg()
 {
 	ut_ad(!rsegs.m_noredo.rseg);
-	ut_ad(!trx_is_autocommit_non_locking(this));
+	ut_ad(!is_autocommit_non_locking());
 	compile_time_assert(ut_is_2pow(TRX_SYS_N_RSEGS));
 
 	/* Choose a temporary rollback segment between 0 and 127
@@ -962,8 +961,8 @@ trx_start_low(
 		    && thd_trx_is_read_only(trx->mysql_thd));
 
 	if (!trx->auto_commit) {
-		++trx->will_lock;
-	} else if (trx->will_lock == 0) {
+		trx->will_lock = true;
+	} else if (!trx->will_lock) {
 		trx->read_only = true;
 	}
 
@@ -1001,7 +1000,7 @@ trx_start_low(
 
 		trx_sys.register_rw(trx);
 	} else {
-		if (!trx_is_autocommit_non_locking(trx)) {
+		if (!trx->is_autocommit_non_locking()) {
 
 			/* If this is a read-only transaction that is writing
 			to a temporary table then it needs a transaction id
@@ -1302,12 +1301,15 @@ inline void trx_t::commit_in_memory(const mtr_t *mtr)
   must_flush_log_later= false;
   read_view.close();
 
-  if (trx_is_autocommit_non_locking(this))
+  if (is_autocommit_non_locking())
   {
     ut_ad(id == 0);
     ut_ad(read_only);
+    ut_ad(!will_lock);
     ut_a(!is_recovered);
     ut_ad(!rsegs.m_redo.rseg);
+    ut_ad(mysql_thd);
+    ut_ad(state == TRX_STATE_ACTIVE);
 
     /* Note: We are asserting without holding the lock mutex. But
     that is OK because this transaction is not waiting and cannot
@@ -1321,12 +1323,11 @@ inline void trx_t::commit_in_memory(const mtr_t *mtr)
     However, the freezing of trx_sys.trx_list will protect the trx_t
     instance and it cannot be removed from the trx_list and freed
     without first unfreezing trx_list. */
-    ut_ad(trx_state_eq(this, TRX_STATE_ACTIVE));
+    state= TRX_STATE_NOT_STARTED;
 
     MONITOR_INC(MONITOR_TRX_NL_RO_COMMIT);
 
     DBUG_LOG("trx", "Autocommit in memory: " << this);
-    state= TRX_STATE_NOT_STARTED;
   }
   else
   {
@@ -1477,8 +1478,6 @@ inline void trx_t::commit_in_memory(const mtr_t *mtr)
 @param mtr  mini-transaction (if there are any persistent modifications) */
 void trx_t::commit_low(mtr_t *mtr)
 {
-  assert_trx_nonlocking_or_in_list(this);
-  ut_ad(!trx_state_eq(this, TRX_STATE_COMMITTED_IN_MEMORY));
   ut_ad(!mtr || mtr->is_active());
   ut_d(bool aborted = in_rollback && error_state == DB_DEADLOCK);
   ut_ad(!mtr == (aborted || !has_logged_or_recovered()));
@@ -1487,13 +1486,13 @@ void trx_t::commit_low(mtr_t *mtr)
   /* undo_no is non-zero if we're doing the final commit. */
   if (fts_trx && undo_no)
   {
-    ut_a(!trx_is_autocommit_non_locking(this));
-    dberr_t error= fts_commit(this);
+    ut_a(!is_autocommit_non_locking());
     /* FTS-FIXME: Temporarily tolerate DB_DUPLICATE_KEY instead of
     dying. This is a possible scenario if there is a crash between
     insert to DELETED table committing and transaction committing. The
     fix would be able to return error from this function */
-    ut_a(error == DB_SUCCESS || error == DB_DUPLICATE_KEY);
+    if (dberr_t error= fts_commit(this))
+      ut_a(error == DB_DUPLICATE_KEY);
   }
 
 #ifndef DBUG_OFF
@@ -1753,8 +1752,6 @@ trx_print_low(
 			/*!< in: mem_heap_get_size(trx->lock.lock_heap) */
 {
 	ibool		newline;
-	const char*	op_info;
-
 	fprintf(f, "TRANSACTION " TRX_ID_FMT, trx_get_id_for_print(trx));
 
 	switch (trx->state) {
@@ -1778,10 +1775,7 @@ trx_print_low(
 	ut_ad(0);
 state_ok:
 
-	/* prevent a race condition */
-	op_info = trx->op_info;
-
-	if (*op_info) {
+	if (const char *op_info = trx->op_info) {
 		putc(' ', f);
 		fputs(op_info, f);
 	}
@@ -2245,7 +2239,7 @@ trx_start_internal_low(
 	/* Ensure it is not flagged as an auto-commit-non-locking
 	transaction. */
 
-	trx->will_lock = 1;
+	trx->will_lock = true;
 
 	trx->internal = true;
 
@@ -2261,7 +2255,7 @@ trx_start_internal_read_only_low(
 	/* Ensure it is not flagged as an auto-commit-non-locking
 	transaction. */
 
-	trx->will_lock = 1;
+	trx->will_lock = true;
 
 	trx->internal = true;
 
@@ -2282,13 +2276,7 @@ trx_start_for_ddl_low(
 		the data dictionary will be locked in crash recovery. */
 
 		trx_set_dict_operation(trx, op);
-
-		/* Ensure it is not flagged as an auto-commit-non-locking
-		transation. */
-		trx->will_lock = 1;
-
 		trx->ddl= true;
-
 		trx_start_internal_low(trx);
 		return;
 
@@ -2315,7 +2303,7 @@ trx_set_rw_mode(
 	trx_t*		trx)		/*!< in/out: transaction that is RW */
 {
 	ut_ad(trx->rsegs.m_redo.rseg == 0);
-	ut_ad(!trx_is_autocommit_non_locking(trx));
+	ut_ad(!trx->is_autocommit_non_locking());
 	ut_ad(!trx->read_only);
 	ut_ad(trx->id == 0);