diff --git a/mysql-test/suite/versioning/r/trx_id.result b/mysql-test/suite/versioning/r/trx_id.result
index ee8be01dc24..c0a9dbcfbe6 100644
--- a/mysql-test/suite/versioning/r/trx_id.result
+++ b/mysql-test/suite/versioning/r/trx_id.result
@@ -492,3 +492,25 @@ SET @@SYSTEM_VERSIONING_ALTER_HISTORY=ERROR;
 SELECT count(*) from mysql.transaction_registry where begin_timestamp>=commit_timestamp;
 count(*)
 0
+# MDEV-18875 Assertion `thd->transaction.stmt.ha_list == __null ||
+# trans == &thd->transaction.stmt' failed or bogus ER_DUP_ENTRY upon
+# ALTER TABLE with versioning
+create or replace table t (x int) engine=innodb;
+set autocommit= 0;
+alter table t
+algorithm=copy,
+add column row_start bigint unsigned as row start,
+add column row_end bigint unsigned as row end,
+add period for system_time(row_start,row_end),
+with system versioning;
+set autocommit= 1;
+# MDEV-18865 Assertion `t->first->versioned_by_id()'
+# failed in innodb_prepare_commit_versioned
+create or replace table t (x int) engine=innodb;
+insert into t values (0);
+alter table t add `row_start` bigint unsigned as row start,
+add `row_end` bigint unsigned as row end,
+add period for system_time(`row_start`,`row_end`),
+modify x int after row_start,
+with system versioning;
+create or replace database test;
diff --git a/mysql-test/suite/versioning/t/trx_id.test b/mysql-test/suite/versioning/t/trx_id.test
index 617c46a9332..38724a47fd1 100644
--- a/mysql-test/suite/versioning/t/trx_id.test
+++ b/mysql-test/suite/versioning/t/trx_id.test
@@ -498,3 +498,30 @@ DROP TABLE t;
 SET @@SYSTEM_VERSIONING_ALTER_HISTORY=ERROR;
 
 SELECT count(*) from mysql.transaction_registry where begin_timestamp>=commit_timestamp;
+
+--echo # MDEV-18875 Assertion `thd->transaction.stmt.ha_list == __null ||
+--echo # trans == &thd->transaction.stmt' failed or bogus ER_DUP_ENTRY upon
+--echo # ALTER TABLE with versioning
+create or replace table t (x int) engine=innodb;
+set autocommit= 0;
+alter table t
+  algorithm=copy,
+  add column row_start bigint unsigned as row start,
+  add column row_end bigint unsigned as row end,
+  add period for system_time(row_start,row_end),
+  with system versioning;
+set autocommit= 1;
+
+--echo # MDEV-18865 Assertion `t->first->versioned_by_id()'
+--echo # failed in innodb_prepare_commit_versioned
+
+create or replace table t (x int) engine=innodb;
+insert into t values (0);
+alter table t add `row_start` bigint unsigned as row start,
+              add `row_end` bigint unsigned as row end,
+              add period for system_time(`row_start`,`row_end`),
+              modify x int after row_start,
+              with system versioning;
+
+
+create or replace database test;
diff --git a/sql/handler.cc b/sql/handler.cc
index 78c61ddf70a..aa3815b2de3 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1513,7 +1513,8 @@ int ha_commit_trans(THD *thd, bool all)
 
 #if 1 // FIXME: This should be done in ha_prepare().
   if (rw_trans || (thd->lex->sql_command == SQLCOM_ALTER_TABLE &&
-                   thd->lex->alter_info.flags & ALTER_ADD_SYSTEM_VERSIONING))
+                   thd->lex->alter_info.flags & ALTER_ADD_SYSTEM_VERSIONING &&
+                   is_real_trans))
   {
     ulonglong trx_start_id= 0, trx_end_id= 0;
     for (Ha_trx_info *ha_info= trans->ha_list; ha_info; ha_info= ha_info->next())
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 36f295749aa..8c139a6facb 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -10920,6 +10920,9 @@ create_table_info_t::create_table_def()
 
 	heap = mem_heap_create(1000);
 
+	ut_d(bool have_vers_start = false);
+	ut_d(bool have_vers_end = false);
+
 	for (ulint i = 0, j = 0; j < n_cols; i++) {
 		Field*	field = m_form->field[i];
 		ulint vers_row = 0;
@@ -10927,8 +10930,10 @@ create_table_info_t::create_table_def()
 		if (m_form->versioned()) {
 			if (i == m_form->s->vers.start_fieldno) {
 				vers_row = DATA_VERS_START;
+				ut_d(have_vers_start = true);
 			} else if (i == m_form->s->vers.end_fieldno) {
 				vers_row = DATA_VERS_END;
+				ut_d(have_vers_end = true);
 			} else if (!(field->flags
 				     & VERS_UPDATE_UNVERSIONED_FLAG)) {
 				vers_row = DATA_VERSIONED;
@@ -11049,6 +11054,10 @@ err_col:
 		j++;
 	}
 
+	ut_ad(have_vers_start == have_vers_end);
+	ut_ad(table->versioned() == have_vers_start);
+	ut_ad(!table->versioned() || table->vers_start != table->vers_end);
+
 	if (num_v) {
 		for (ulint i = 0, j = 0; i < n_cols; i++) {
 			dict_v_col_t*	v_col;
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index 5bf31e13b93..36721f1942a 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -1854,10 +1854,14 @@ struct dict_table_t {
 	/** Add the table definition to the data dictionary cache */
 	void add_to_cache();
 
+	/** @return whether the table is versioned.
+	It is assumed that both vers_start and vers_end set to 0
+	iff table is not versioned. In any other case,
+	these fields correspond to actual positions in cols[]. */
 	bool versioned() const { return vers_start || vers_end; }
 	bool versioned_by_id() const
 	{
-		return vers_start && cols[vers_start].mtype == DATA_INT;
+		return versioned() && cols[vers_start].mtype == DATA_INT;
 	}
 
 	void inc_fk_checks()