Merge 10.2 into 10.3

18 files changed, 638 insertions, 242 deletions

diff --git a/sql/item.cc b/sql/item.cc
index b8a20580067..d5a4b4363d3 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -6129,6 +6129,7 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
             */
             set_max_sum_func_level(thd, select);
             set_field(new_field);
+            depended_from= (*((Item_field**)res))->depended_from;
             return 0;
           }
           else
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index bedf85e3699..9f43561151d 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2002, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2016, MariaDB
+   Copyright (c) 2010, 2021, MariaDB
 
    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
@@ -1779,7 +1779,6 @@ double Item_in_subselect::val_real()
     As far as Item_in_subselect called only from Item_in_optimizer this
     method should not be used
   */
-  DBUG_ASSERT(0);
   DBUG_ASSERT(fixed == 1);
   if (forced_const)
     return value;
@@ -2255,11 +2254,12 @@ Item_in_subselect::create_single_in_to_exists_cond(JOIN *join,
     */
     Item *item= (Item*) select_lex->item_list.head();
 
-    if (select_lex->table_list.elements)
+    if (select_lex->table_list.elements ||
+        !(select_lex->master_unit()->is_unit_op()))
     {
       Item *having= item;
       Item *orig_item= item;
-       
+
       item= func->create(thd, expr, item);
       if (!abort_on_null && orig_item->maybe_null)
       {
@@ -2303,32 +2303,28 @@ Item_in_subselect::create_single_in_to_exists_cond(JOIN *join,
     }
     else
     {
-      if (select_lex->master_unit()->is_unit_op())
-      {
-        LEX_CSTRING field_name= {STRING_WITH_LEN("<result>") };
-        Item *new_having=
-          func->create(thd, expr,
-                       new (thd->mem_root) Item_ref_null_helper(thd,
+      DBUG_ASSERT(select_lex->master_unit()->is_unit_op());
+      LEX_CSTRING field_name= {STRING_WITH_LEN("<result>") };
+      Item *new_having=
+        func->create(thd, expr,
+                     new (thd->mem_root) Item_ref_null_helper(thd,
                                                   &select_lex->context,
                                                   this,
                                                   &select_lex->ref_pointer_array[0],
                                                   (char *)"<no matter>",
                                                   &field_name));
-        if (!abort_on_null && left_expr->maybe_null)
-        {
-          disable_cond_guard_for_const_null_left_expr(0);
-          if (!(new_having= new (thd->mem_root) Item_func_trig_cond(thd, new_having,
+      if (!abort_on_null && left_expr->maybe_null)
+      {
+        disable_cond_guard_for_const_null_left_expr(0);
+        if (!(new_having= new (thd->mem_root) Item_func_trig_cond(thd, new_having,
                                                             get_cond_guard(0))))
-            DBUG_RETURN(true);
-        }
-
-        new_having->name= in_having_cond;
-        if (fix_having(new_having, select_lex))
           DBUG_RETURN(true);
-        *having_item= new_having;
       }
-      else
-        DBUG_ASSERT(false);
+
+      new_having->name= in_having_cond;
+      if (fix_having(new_having, select_lex))
+        DBUG_RETURN(true);
+      *having_item= new_having;
     }
   }
 
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 612e905ef68..f53bb9f7451 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -5407,7 +5407,7 @@ static int init_server_components()
     }
   }
 
-  if (opt_bin_log)
+  if (!opt_help && opt_bin_log)
   {
     if (mysql_bin_log.open_index_file(opt_binlog_index_name, opt_bin_logname,
                                       TRUE))
diff --git a/sql/mysqld.h b/sql/mysqld.h
index 47f19b76c93..4f6709f37f4 100644
--- a/sql/mysqld.h
+++ b/sql/mysqld.h
@@ -582,7 +582,7 @@ extern ulonglong my_pcre_frame_size;
  */
 extern my_bool opt_large_pages;
 extern uint opt_large_page_size;
-extern char lc_messages_dir[FN_REFLEN];
+extern MYSQL_PLUGIN_IMPORT char lc_messages_dir[FN_REFLEN];
 extern char *lc_messages_dir_ptr, *log_error_file_ptr;
 extern MYSQL_PLUGIN_IMPORT char reg_ext[FN_EXTLEN];
 extern MYSQL_PLUGIN_IMPORT uint reg_ext_length;
diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index bd41de78c9a..525d836b8c3 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -3426,8 +3426,7 @@ sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
 #endif
 
   if (open_tables)
-    res= check_dependencies_in_with_clauses(m_lex->with_clauses_list) ||
-         instr->exec_open_and_lock_tables(thd, m_lex->query_tables);
+    res= instr->exec_open_and_lock_tables(thd, m_lex->query_tables);
 
   if (likely(!res))
   {
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 521e187773a..f793556cf62 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -3520,7 +3520,11 @@ open_and_process_table(THD *thd, TABLE_LIST *tables, uint *counter, uint flags,
   if (tables->derived)
   {
     if (!tables->view)
+    {
+      if (!tables->is_derived())
+        tables->set_derived();
       goto end;
+    }
     /*
       We restore view's name and database wiped out by derived tables
       processing and fall back to standard open process in order to
@@ -3530,35 +3534,6 @@ open_and_process_table(THD *thd, TABLE_LIST *tables, uint *counter, uint flags,
     tables->db= tables->view_db;
     tables->table_name= tables->view_name;
   }
-  else if (tables->select_lex) 
-  {
-    /*
-      Check whether 'tables' refers to a table defined in a with clause.
-      If so set the reference to the definition in tables->with.
-    */ 
-    if (!tables->with)
-      tables->with= tables->select_lex->find_table_def_in_with_clauses(tables);
-    /*
-      If 'tables' is defined in a with clause set the pointer to the
-      specification from its definition in tables->derived.
-    */
-    if (tables->with)
-    {
-      if (tables->is_recursive_with_table() &&
-          !tables->is_with_table_recursive_reference())
-      {
-        tables->with->rec_outer_references++;
-        With_element *with_elem= tables->with;
-        while ((with_elem= with_elem->get_next_mutually_recursive()) !=
-               tables->with)
-	  with_elem->rec_outer_references++;
-      }
-      if (tables->set_as_with_table(thd, tables->with))
-        DBUG_RETURN(1);
-      else
-        goto end;
-    }
-  }
 
   if (!tables->derived && is_infoschema_db(&tables->db))
   {
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index c4905fcabf6..6e89da1ee14 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -2736,6 +2736,60 @@ void THD::close_active_vio()
 #endif
 
 
+/*
+  @brief MySQL parser used for recursive invocations
+
+  @param old_lex  The LEX structure in the state when this parser
+                  is called recursively
+  @param lex      The LEX structure used to parse a new SQL fragment
+  @param str      The SQL fragment to parse
+  @param str_len  The length of the SQL fragment to parse
+  @param stmt_prepare_mode true <=> when parsing a prepare statement
+
+  @details
+    This function is to be used when parsing of an SQL fragment is
+    needed within one of the grammar rules.
+
+  @notes
+    Currently the function is used only when the specification of a CTE
+    is parsed for the not first and not recursive references of the CTE.
+
+  @retval false   On a successful parsing of the fragment
+  @retval true    Otherwise
+*/
+
+bool THD::sql_parser(LEX *old_lex, LEX *lex,
+                     char *str, uint str_len, bool stmt_prepare_mode)
+{
+  extern int MYSQLparse(THD * thd);
+
+  bool parse_status= false;
+  Parser_state parser_state;
+  Parser_state *old_parser_state= m_parser_state;
+
+  if (parser_state.init(this, str, str_len))
+    return true;
+
+  m_parser_state= &parser_state;
+  parser_state.m_lip.stmt_prepare_mode= stmt_prepare_mode;
+  parser_state.m_lip.multi_statements= false;
+  parser_state.m_lip.m_digest= NULL;
+
+  lex->param_list= old_lex->param_list;
+  lex->sphead= old_lex->sphead;
+  lex->spname= old_lex->spname;
+  lex->spcont= old_lex->spcont;
+  lex->sp_chistics= old_lex->sp_chistics;
+  lex->trg_chistics= old_lex->trg_chistics;
+
+  parse_status= MYSQLparse(this) != 0;
+
+  m_parser_state= old_parser_state;
+
+  return parse_status;
+}
+
+
 struct Item_change_record: public ilink
 {
   Item **place;
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 2b6ac5e7aba..133c0f6fec5 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2000, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2020, MariaDB Corporation.
+   Copyright (c) 2009, 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
@@ -958,7 +958,7 @@ mysqld_collation_get_by_name(const char *name,
 
 static inline bool is_supported_parser_charset(CHARSET_INFO *cs)
 {
-  return MY_TEST(cs->mbminlen == 1);
+  return MY_TEST(cs->mbminlen == 1 && cs->number != 17 /* filename */);
 }
 
 #ifdef MYSQL_SERVER
@@ -4226,15 +4226,11 @@ public:
         to resolve all CTE names as we don't need this message to be thrown
         for any CTE references.
       */
-      if (!lex->with_clauses_list)
+      if (!lex->with_cte_resolution)
       {
         my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
         return TRUE;
       }
-      /* This will allow to throw an error later for non-CTE references */
-      to->str= NULL;
-      to->length= 0;
-      return FALSE;
     }
 
     to->str= strmake(db.str, db.length);
@@ -4839,6 +4835,9 @@ public:
     mysql_mutex_unlock(&LOCK_thread_count);
   }
 
+  bool sql_parser(LEX *old_lex, LEX *lex,
+                  char *str, uint str_len, bool stmt_prepare_mode);
+
 
   uint get_net_wait_timeout()
   {
diff --git a/sql/sql_cte.cc b/sql/sql_cte.cc
index b5946a6c31d..933b36f423f 100644
--- a/sql/sql_cte.cc
+++ b/sql/sql_cte.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2016, 2017 MariaDB
+   Copyright (c) 2016, 2021, MariaDB
 
    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
@@ -75,7 +75,7 @@ bool With_clause::add_with_element(With_element *elem)
     true    on failure
 */
 
-bool check_dependencies_in_with_clauses(With_clause *with_clauses_list)
+bool LEX::check_dependencies_in_with_clauses()
 {
   for (With_clause *with_clause= with_clauses_list;
        with_clause;
@@ -93,6 +93,200 @@ bool check_dependencies_in_with_clauses(With_clause *with_clauses_list)
 
 /**
   @brief
+    Resolve references to CTE in specification of hanging CTE
+
+  @details
+    A CTE to which there are no references in the query is called hanging CTE.
+    Although such CTE is not used for execution its specification must be
+    subject to context analysis. All errors concerning references to
+    non-existing tables or fields occurred in the specification must be
+    reported as well as all other errors caught at the prepare stage.
+    The specification of a hanging CTE might contain references to other
+    CTE outside of the specification and within it if the specification
+    contains a with clause. This function resolves all such references for
+    all hanging CTEs encountered in the processed query.
+
+  @retval
+    false   on success
+    true    on failure
+*/
+
+bool
+LEX::resolve_references_to_cte_in_hanging_cte()
+{
+  for (With_clause *with_clause= with_clauses_list;
+       with_clause; with_clause= with_clause->next_with_clause)
+  {
+    for (With_element *with_elem= with_clause->with_list.first;
+         with_elem; with_elem= with_elem->next)
+    {
+      if (!with_elem->is_referenced())
+      {
+        TABLE_LIST *first_tbl=
+                     with_elem->spec->first_select()->table_list.first;
+        TABLE_LIST **with_elem_end_pos= with_elem->head->tables_pos.end_pos;
+        if (first_tbl && resolve_references_to_cte(first_tbl, with_elem_end_pos))
+          return true;
+      }
+    }
+  }
+  return false;
+}
+
+
+/**
+  @brief
+    Resolve table references to CTE from a sub-chain of table references
+
+  @param tables      Points to the beginning of the sub-chain
+  @param tables_last Points to the address with the sub-chain barrier
+
+  @details
+    The method resolves tables references to CTE from the chain of
+    table references specified by the parameters 'tables' and 'tables_last'.
+    It resolves the references against the CTE definition occurred in a query
+    or the specification of a CTE whose parsing tree is represented by
+    this LEX structure. The method is always called right after the process
+    of parsing the query or of the specification of a CTE has been finished,
+    thus the chain of table references used in the parsed fragment has been
+    already built. It is assumed that parameters of the method specify a
+    a sub-chain of this chain.
+    If a table reference can be potentially a table reference to a CTE and it
+    has not been resolved yet then the method tries to find the definition
+    of the CTE against which the reference can be resolved. If it succeeds
+    it sets the field TABLE_LIST::with to point to the found definition.
+    It also sets the field TABLE_LIST::derived to point to the specification
+    of the found CTE and sets TABLE::db.str to empty_c_string. This will
+    allow to handle this table reference like a reference to a derived handle.
+    If another table reference has been already resolved against this CTE
+    and this CTE is not recursive then a clone of the CTE specification is
+    constructed using the function With_element::clone_parsed_spec() and
+    TABLE_LIST::derived is set to point to this clone rather than to the
+    original specification.
+    If the method does not find a matched CTE definition in the parsed fragment
+    then in the case when the flag this->only_cte_resolution is set to true
+    it just moves to the resolution of the next table reference from the
+    specified sub-chain while in the case when this->only_cte_resolution is set
+    to false the method additionally sets an mdl request for this table
+    reference.
+
+  @notes
+    The flag this->only_cte_resolution is set to true in the cases when
+    the failure to resolve a table reference as a CTE reference within
+    the fragment associated with this LEX structure does not imply that
+    this table reference cannot be resolved as such at all.
+
+  @retval false  On success: no errors reported, no memory allocations failed
+  @retval true   Otherwise
+*/
+
+bool LEX::resolve_references_to_cte(TABLE_LIST *tables,
+                                    TABLE_LIST **tables_last)
+{
+  With_element *with_elem= 0;
+
+  for (TABLE_LIST *tbl= tables; tbl != *tables_last; tbl= tbl->next_global)
+  {
+    if (tbl->derived)
+      continue;
+    if (!tbl->db.length && !tbl->with)
+      tbl->with= tbl->select_lex->find_table_def_in_with_clauses(tbl);
+    if (!tbl->with)    // no CTE matches table reference tbl
+    {
+      if (only_cte_resolution)
+        continue;
+      if (!tbl->db.length)   // no database specified in table reference tbl
+      {
+        if (!thd->db.length) // no default database is set
+        {
+          my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
+          return true;
+        }
+        if (copy_db_to(&tbl->db))
+          return true;
+        if (!(tbl->table_options & TL_OPTION_ALIAS))
+          tbl->mdl_request.init(MDL_key::TABLE, tbl->db.str,
+                                tbl->table_name.str,
+                                tbl->mdl_type, MDL_TRANSACTION);
+        tbl->mdl_request.set_type((tbl->lock_type >= TL_WRITE_ALLOW_WRITE) ?
+                                   MDL_SHARED_WRITE : MDL_SHARED_READ);
+      }
+      continue;
+    }
+    with_elem= tbl->with;
+    if (tbl->is_recursive_with_table() &&
+        !tbl->is_with_table_recursive_reference())
+    {
+      tbl->with->rec_outer_references++;
+      while ((with_elem= with_elem->get_next_mutually_recursive()) !=
+             tbl->with)
+	with_elem->rec_outer_references++;
+    }
+    if (!with_elem->is_used_in_query || with_elem->is_recursive)
+    {
+      tbl->derived= with_elem->spec;
+      if (tbl->derived != tbl->select_lex->master_unit() &&
+          !with_elem->is_recursive &&
+          !tbl->is_with_table_recursive_reference())
+      {
+        tbl->derived->move_as_slave(tbl->select_lex);
+      }
+      with_elem->is_used_in_query= true;
+    }
+    else
+    {
+      if (!(tbl->derived= tbl->with->clone_parsed_spec(thd->lex, tbl)))
+        return true;
+    }
+    tbl->db.str= empty_c_string;
+    tbl->db.length= 0;
+    tbl->schema_table= 0;
+    if (tbl->derived)
+    {
+      tbl->derived->first_select()->linkage= DERIVED_TABLE_TYPE;
+    }
+    if (tbl->with->is_recursive && tbl->is_with_table_recursive_reference())
+      continue;
+    with_elem->inc_references();
+  }
+  return false;
+}
+
+
+/**
+  @brief
+    Find out dependencies between CTEs, resolve references to them
+
+  @details
+    The function can be called in two modes. With this->with_cte_resolution
+    set to false the function only finds out all dependencies between CTEs
+    used in a query expression with a WITH clause whose parsing has been
+    just finished. Based on these dependencies recursive CTEs are detected.
+    If this->with_cte_resolution is set to true the function additionally
+    resolves all references to CTE occurred in this query expression.
+
+  @retval
+    true   on failure
+    false  on success
+*/
+
+bool
+LEX::check_cte_dependencies_and_resolve_references()
+{
+  if (check_dependencies_in_with_clauses())
+    return true;
+  if (!with_cte_resolution)
+    return false;
+  if (resolve_references_to_cte(query_tables, query_tables_last))
+    return true;
+  if (resolve_references_to_cte_in_hanging_cte())
+    return true;
+  return false;
+}
+
+
+/**
+  @brief
     Check dependencies between tables defined in this with clause
 
  @details
@@ -129,10 +323,11 @@ bool With_clause::check_dependencies()
          elem != with_elem;
          elem= elem->next)
     {
-      if (lex_string_cmp(system_charset_info, with_elem->query_name,
-                         elem->query_name) == 0)
+      if (my_strcasecmp(system_charset_info, with_elem->get_name_str(),
+                        elem->get_name_str()) == 0)
       {
-	my_error(ER_DUP_QUERY_NAME, MYF(0), with_elem->query_name->str);
+        my_error(ER_DUP_QUERY_NAME, MYF(0),
+                 with_elem->get_name_str());
 	return true;
       }
     }
@@ -239,13 +434,12 @@ With_element *With_clause::find_table_def(TABLE_LIST *table,
        with_elem != barrier;
        with_elem= with_elem->next)
   {
-    if (my_strcasecmp(system_charset_info, with_elem->query_name->str,
+    if (my_strcasecmp(system_charset_info, with_elem->get_name_str(),
 		      table->table_name.str) == 0 &&
         !table->is_fqtn)
     {
       table->set_derived();
-      table->db.str= empty_c_string;
-      table->db.length= 0;
+      with_elem->referenced= true;
       return with_elem;
     }
   }
@@ -602,7 +796,7 @@ bool With_clause::check_anchors()
       if (elem == with_elem)
       {
         my_error(ER_RECURSIVE_WITHOUT_ANCHORS, MYF(0),
-        with_elem->query_name->str);
+        with_elem->get_name_str());
         return true;
       }
     }
@@ -635,7 +829,7 @@ bool With_clause::check_anchors()
         if (elem->work_dep_map & elem->get_elem_map())
 	{
           my_error(ER_UNACCEPTABLE_MUTUAL_RECURSION, MYF(0),
-          with_elem->query_name->str);
+          with_elem->get_name_str());
           return true;
 	}
       }
@@ -787,7 +981,8 @@ bool With_element::set_unparsed_spec(THD *thd, char *spec_start, char *spec_end,
   @brief
    Create a clone of the specification for the given with table
     
-  @param thd        The context of the statement containing this with element
+  @param old_lex    The LEX structure created for the query or CTE specification
+                    where this With_element is defined
   @param with_table The reference to the table defined in this element for which
                      the clone is created.
 
@@ -797,12 +992,13 @@ bool With_element::set_unparsed_spec(THD *thd, char *spec_start, char *spec_end,
     this element.
     The clone is created when the string with the specification saved in
     unparsed_spec is fed into the parser as an input string. The parsing
-    this string a unit object representing the specification is build.
+    this string a unit object representing the specification is built.
     A chain of all table references occurred in the specification is also
     formed.
     The method includes the new unit and its sub-unit into hierarchy of
     the units of the main query. I also insert the constructed chain of the 
     table references into the chain of all table references of the main query.
+    The method resolves all references to CTE in the clone.
 
   @note
     Clones is created only for not first references to tables defined in
@@ -818,115 +1014,129 @@ bool With_element::set_unparsed_spec(THD *thd, char *spec_start, char *spec_end,
      NULL - otherwise
 */
 
-st_select_lex_unit *With_element::clone_parsed_spec(THD *thd,
+st_select_lex_unit *With_element::clone_parsed_spec(LEX *old_lex,
                                                     TABLE_LIST *with_table)
 {
+  THD *thd= old_lex->thd;
   LEX *lex;
-  st_select_lex_unit *res= NULL; 
-  Query_arena backup;
-  Query_arena *arena= thd->activate_stmt_arena_if_needed(&backup);
+  st_select_lex_unit *res= NULL;
 
   if (!(lex= (LEX*) new(thd->mem_root) st_lex_local))
-  {
-    if (arena)
-      thd->restore_active_arena(arena, &backup);
     return res;
-  }
-  LEX *old_lex= thd->lex;
   thd->lex= lex;
 
   bool parse_status= false;
-  Parser_state parser_state;
-  TABLE_LIST *spec_tables;
-  TABLE_LIST *spec_tables_tail;
   st_select_lex *with_select;
 
   char save_end= unparsed_spec.str[unparsed_spec.length];
-  ((char*) &unparsed_spec.str[unparsed_spec.length])[0]= '\0';
-  if (parser_state.init(thd, (char*) unparsed_spec.str, (unsigned int)unparsed_spec.length))
-    goto err;
-  parser_state.m_lip.stmt_prepare_mode= stmt_prepare_mode;
-  parser_state.m_lip.multi_statements= false;
-  parser_state.m_lip.m_digest= NULL;
+  const_cast<char*>(unparsed_spec.str)[unparsed_spec.length]= '\0';
 
   lex_start(thd);
   lex->clone_spec_offset= unparsed_spec_offset;
-  lex->param_list= old_lex->param_list;
-  lex->sphead= old_lex->sphead;
-  lex->spname= old_lex->spname;
-  lex->spcont= old_lex->spcont;
-  lex->sp_chistics= old_lex->sp_chistics;
-
-  lex->stmt_lex= old_lex;
-  with_select= &lex->select_lex;
-  with_select->select_number= ++thd->lex->stmt_lex->current_select_number;
-  parse_status= parse_sql(thd, &parser_state, 0);
-  ((char*) &unparsed_spec.str[unparsed_spec.length])[0]= save_end;
+  lex->with_cte_resolution= true;
 
-  if (parse_status)
-    goto err;
+  /*
+    The specification of a CTE is to be parsed as a regular query.
+    At the very end of the parsing query the function
+    check_cte_dependencies_and_resolve_references() will be called.
+    It will check the dependencies between CTEs that are defined
+    within the query and will resolve CTE references in this query.
+    If a table reference is not resolved as a CTE reference within
+    this query it still can be resolved as a reference to a CTE defined
+    in the same clause as the CTE whose specification is to be parsed
+    or defined in an embedding CTE definition.
+
+    Example:
+      with
+      cte1 as ( ... ),
+      cte2 as ([WITH ...] select ... from cte1 ...)
+      select ... from cte2 as r, ..., cte2 as s ...
+
+    Here the specification of cte2 has be cloned for table reference
+    with alias s1. The specification contains a reference to cte1
+    that is defined outside this specification. If the reference to
+    cte1 cannot be resolved within the specification of cte2 it's
+    not necessarily has to be a reference to a non-CTE table. That's
+    why the flag lex->only_cte_resolution has to be set to true
+    before parsing of the specification of cte2 invoked by this
+    function starts. Otherwise an mdl_lock would be requested for s
+    and this would not be correct.
+  */
+
+  lex->only_cte_resolution= true;
+
+  lex->stmt_lex= old_lex->stmt_lex ? old_lex->stmt_lex : old_lex;
+
+  parse_status= thd->sql_parser(old_lex, lex,
+                                (char*) unparsed_spec.str,
+                                (unsigned int)unparsed_spec.length,
+                                stmt_prepare_mode);
 
-  if (check_dependencies_in_with_clauses(lex->with_clauses_list))
+  const_cast<char*>(unparsed_spec.str)[unparsed_spec.length]= save_end;
+  with_select= lex->unit.first_select();
+  with_select->select_number= ++lex->stmt_lex->current_select_number;
+
+  if (parse_status)
     goto err;
 
-  spec_tables= lex->query_tables;
-  spec_tables_tail= 0;
-  for (TABLE_LIST *tbl= spec_tables;
-       tbl;
-       tbl= tbl->next_global)
-  {
-    if (!tbl->derived && !tbl->schema_table &&
-        thd->open_temporary_table(tbl))
-      goto err;
-    spec_tables_tail= tbl;
-  }
-  if (spec_tables)
+  /*
+    The global chain of TABLE_LIST objects created for the specification that
+    just has been parsed is added to such chain that contains the reference
+    to the CTE whose specification is parsed right after the TABLE_LIST object
+    created for the reference.
+  */
+  if (lex->query_tables)
   {
-    if (with_table->next_global)
+    head->tables_pos.set_start_pos(&with_table->next_global);
+    head->tables_pos.set_end_pos(lex->query_tables_last);
+    TABLE_LIST *next_tbl= with_table->next_global;
+    if (next_tbl)
     {
-      spec_tables_tail->next_global= with_table->next_global;
-      with_table->next_global->prev_global= &spec_tables_tail->next_global;
+      *(lex->query_tables->prev_global= next_tbl->prev_global)=
+        lex->query_tables;
+      *(next_tbl->prev_global= lex->query_tables_last)= next_tbl;
     }
     else
     {
-      old_lex->query_tables_last= &spec_tables_tail->next_global;
+      *(lex->query_tables->prev_global= old_lex->query_tables_last)=
+        lex->query_tables;
+      old_lex->query_tables_last= lex->query_tables_last;
     }
-    spec_tables->prev_global= &with_table->next_global;
-    with_table->next_global= spec_tables;
   }
   res= &lex->unit;
   res->with_element= this;
   
+  /*
+    The unit of the specification that just has been parsed is included
+    as a slave of the select that contained in its from list the table
+    reference for which the unit has been created.
+  */
   lex->unit.include_down(with_table->select_lex);
-  lex->unit.set_slave(with_select); 
+  lex->unit.set_slave(with_select);
+  lex->unit.cloned_from= spec;
   old_lex->all_selects_list=
     (st_select_lex*) (lex->all_selects_list->
 		      insert_chain_before(
 			(st_select_lex_node **) &(old_lex->all_selects_list),
                         with_select));
-  if (check_dependencies_in_with_clauses(lex->with_clauses_list))
-    res= NULL;
+
   /*
-    Resolve references to CTE from the spec_tables list that has not
-    been resolved yet.
+    Now all references to the CTE defined outside of the cloned specification
+    has to be resolved. Additionally if old_lex->only_cte_resolution == false
+    for the table references that has not been resolved requests for mdl_locks
+    has to be set.
   */
-  for (TABLE_LIST *tbl= spec_tables;
-       tbl;
-       tbl= tbl->next_global)
+  lex->only_cte_resolution= old_lex->only_cte_resolution;
+  if (lex->resolve_references_to_cte(lex->query_tables,
+                                     lex->query_tables_last))
   {
-    if (!tbl->with)
-      tbl->with= with_select->find_table_def_in_with_clauses(tbl);
-    if (tbl == spec_tables_tail)
-      break;
-  }
-  if (check_table_access(thd, SELECT_ACL, spec_tables, FALSE, UINT_MAX, FALSE))
+    res= NULL;
     goto err;
+  }
 
-  lex->sphead= NULL;    // in order not to delete lex->sphead
+ lex->sphead= NULL;    // in order not to delete lex->sphead
   lex_end(lex);
 err:
-  if (arena)
-    thd->restore_active_arena(arena, &backup);
   thd->lex= old_lex;
   return res;
 }
@@ -1096,58 +1306,6 @@ With_element *st_select_lex::find_table_def_in_with_clauses(TABLE_LIST *table)
 }
 
 
-/**
-   @brief
-     Set the specifying unit in this reference to a with table  
-     
-  @details  
-    The method assumes that the given element with_elem defines the table T
-    this table reference refers to.
-    If this is the first reference to T the method just sets its specification
-    in the field 'derived' as the unit that yields T. Otherwise the method  
-    first creates a clone specification and sets rather this clone in this field.
- 
-  @retval
-    false   on success
-    true    on failure
-*/    
-
-bool TABLE_LIST::set_as_with_table(THD *thd, With_element *with_elem)
-{
-  if (table)
-  {
-    /*
-      This table was prematurely identified as a temporary table.
-      We correct it here, but it's not a nice solution in the case
-      when the temporary table with this name is not used anywhere
-      else in the query.
-    */
-    thd->mark_tmp_table_as_free_for_reuse(table);
-    table= 0;
-  }
-  with= with_elem;
-  schema_table= NULL;
-  if (!with_elem->is_referenced() || with_elem->is_recursive)
-  {
-    derived= with_elem->spec;
-    if (derived != select_lex->master_unit() &&
-        !with_elem->is_recursive &&
-        !is_with_table_recursive_reference())
-    {
-       derived->move_as_slave(select_lex);
-    }
-  }
-  else 
-  {
-    if(!(derived= with_elem->clone_parsed_spec(thd, this)))
-      return true;
-  }
-  derived->first_select()->linkage= DERIVED_TABLE_TYPE;
-  with_elem->inc_references();
-  return false;
-}
-
-
 bool TABLE_LIST::is_recursive_with_table()
 {
   return with && with->is_recursive;
@@ -1247,7 +1405,7 @@ bool st_select_lex::check_unrestricted_recursive(bool only_standard_compliant)
   if (only_standard_compliant && with_elem->is_unrestricted())
   {
     my_error(ER_NOT_STANDARD_COMPLIANT_RECURSIVE,
-	     MYF(0), with_elem->query_name->str);
+             MYF(0), with_elem->get_name_str());
     return true;
   }
 
@@ -1447,7 +1605,7 @@ void With_clause::print(String *str, enum_query_type query_type)
 
 void With_element::print(String *str, enum_query_type query_type)
 {
-  str->append(query_name);
+  str->append(get_name());
   if (column_list.elements)
   {
     List_iterator_fast<LEX_CSTRING> li(column_list);
diff --git a/sql/sql_cte.h b/sql/sql_cte.h
index bda62271649..750a01e002a 100644
--- a/sql/sql_cte.h
+++ b/sql/sql_cte.h
@@ -25,6 +25,39 @@ struct st_unit_ctxt_elem;
 
 
 /**
+  @class With_element_head
+  @brief Head of the definition of a CTE table
+
+  It contains the name of the CTE and it contains the position of the subchain
+  of table references used in the definition in the global chain of table
+  references used in the query where this definition is encountered.
+*/
+
+class With_element_head : public Sql_alloc
+{
+  /* The name of the defined CTE */
+  LEX_CSTRING *query_name;
+
+public:
+  /*
+    The structure describing the subchain of the table references used in
+    the specification of the defined CTE in the global chain of table
+    references used in the query. The structure is fully defined only
+    after the CTE definition has been parsed.
+  */
+  TABLE_CHAIN tables_pos;
+
+  With_element_head(LEX_CSTRING *name)
+    : query_name(name)
+  {
+    tables_pos.set_start_pos(0);
+    tables_pos.set_end_pos(0);
+  }
+  friend class With_element;
+};
+
+
+/**
   @class With_element
   @brief Definition of a CTE table
 	
@@ -85,9 +118,22 @@ private:
     subqueries and specifications of other with elements).
   */ 
   uint references;
+
+  /*
+    true <=> this With_element is referred in the query in which the
+    element is defined
+  */
+  bool referenced;
+
+  /*
+    true <=> this With_element is needed for the execution of the query
+    in which the element is defined
+  */
+  bool is_used_in_query;
+
   /* 
     Unparsed specification of the query that specifies this element.
-    It used to build clones of the specification if they are needed.
+    It's used to build clones of the specification if they are needed.
   */
   LEX_CSTRING unparsed_spec;
   /* Offset of the specification in the input string */
@@ -101,10 +147,11 @@ private:
  
 public:
   /*
-    The name of the table introduced by this with elememt. The name
-     can be used in FROM lists of the queries in the scope of the element.
+    Contains the name of the defined With element and the position of
+    the subchain of the tables references used by its definition in the
+    global chain of TABLE_LIST objects created for the whole query.
   */
-  LEX_CSTRING *query_name;
+  With_element_head *head;
   /*
     Optional list of column names to name the columns of the table introduced
     by this with element. It is used in the case when the names are not
@@ -162,18 +209,27 @@ public:
   /* List of derived tables containing recursive references to this CTE */
   SQL_I_List<TABLE_LIST> derived_with_rec_ref;
 
-  With_element(LEX_CSTRING *name,
+  With_element(With_element_head *h,
                List <LEX_CSTRING> list,
                st_select_lex_unit *unit)
     : next(NULL), base_dep_map(0), derived_dep_map(0),
       sq_dep_map(0), work_dep_map(0), mutually_recursive(0),
       top_level_dep_map(0), sq_rec_ref(NULL),
       next_mutually_recursive(NULL), references(0), 
-      query_name(name), column_list(list), spec(unit),
+      referenced(false), is_used_in_query(false),
+      head(h), column_list(list), spec(unit),
       is_recursive(false), rec_outer_references(0), with_anchor(false),
       level(0), rec_result(NULL)
   { unit->with_element= this; }
 
+  LEX_CSTRING *get_name() { return head->query_name; }
+  const char *get_name_str() { return get_name()->str; }
+
+  void set_tables_start_pos(TABLE_LIST **pos)
+  { head->tables_pos.set_start_pos(pos); }
+  void set_tables_end_pos(TABLE_LIST **pos)
+  { head->tables_pos.set_end_pos(pos); }
+
   bool check_dependencies_in_spec();
   
   void check_dependencies_in_select(st_select_lex *sl, st_unit_ctxt_elem *ctxt,
@@ -200,9 +256,9 @@ public:
   bool set_unparsed_spec(THD *thd, char *spec_start, char *spec_end,
                          my_ptrdiff_t spec_offset);
 
-  st_select_lex_unit *clone_parsed_spec(THD *thd, TABLE_LIST *with_table);
+  st_select_lex_unit *clone_parsed_spec(LEX *old_lex, TABLE_LIST *with_table);
 
-  bool is_referenced() { return references != 0; }
+  bool is_referenced() { return referenced; }
 
   void inc_references() { references++; }
 
@@ -260,6 +316,12 @@ public:
   void prepare_for_next_iteration();
 
   friend class With_clause;
+
+  friend
+  bool LEX::resolve_references_to_cte(TABLE_LIST *tables,
+                                      TABLE_LIST **tables_last);
+  friend
+  bool LEX::resolve_references_to_cte_in_hanging_cte();
 };
 
 const uint max_number_of_elements_in_with_clause= sizeof(table_map)*8;
@@ -356,8 +418,10 @@ public:
   friend class With_element;
 
   friend
-  bool
-  check_dependencies_in_with_clauses(With_clause *with_clauses_list);
+  bool LEX::check_dependencies_in_with_clauses();
+
+  friend
+  bool LEX::resolve_references_to_cte_in_hanging_cte();
 };
 
 inline
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 4f90fb28b45..2a337b0f842 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2019, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2020, MariaDB Corporation
+   Copyright (c) 2009, 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
@@ -702,6 +702,8 @@ void LEX::start(THD *thd_arg)
   explain_json= false;
   context_analysis_only= 0;
   derived_tables= 0;
+  with_cte_resolution= false;
+  only_cte_resolution= false;
   safe_to_cache_query= 1;
   parsing_options.reset();
   empty_field_list_on_rset= 0;
@@ -2300,6 +2302,7 @@ void st_select_lex_unit::init_query()
   is_view= false;
   with_clause= 0;
   with_element= 0;
+  cloned_from= 0;
   columns_are_renamed= false;
   intersect_mark= NULL;
   with_wrapped_tvc= false;
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 748e6180642..ce306eab9fe 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -846,6 +846,8 @@ public:
   With_clause *with_clause;
   /* With element where this unit is used as the specification (if any) */
   With_element *with_element;
+  /* The unit used as a CTE specification from which this unit is cloned */
+  st_select_lex_unit *cloned_from;
   /* thread handler */
   THD *thd;
   /*
@@ -1378,7 +1380,9 @@ public:
   }
   With_element *get_with_element()
   {
-    return master_unit()->with_element;
+    return master_unit()->cloned_from ?
+           master_unit()->cloned_from->with_element :
+           master_unit()->with_element;
   }
   With_element *find_table_def_in_with_clauses(TABLE_LIST *table);
   bool check_unrestricted_recursive(bool only_standard_compliant);
@@ -3062,6 +3066,20 @@ public:
   */
   uint8 derived_tables;
   uint8 context_analysis_only;
+  /*
+    true <=> The parsed fragment requires resolution of references to CTE
+    at the end of parsing. This name resolution process involves searching
+    for possible dependencies between CTE defined in the parsed fragment and
+    detecting possible recursive references.
+    The flag is set to true if the fragment contains CTE definitions.
+  */
+  bool with_cte_resolution;
+  /*
+    true <=> only resolution of references to CTE are required in the parsed
+    fragment, no checking of dependencies between CTE is required.
+    This flag is used only when parsing clones of CTE specifications.
+  */
+  bool only_cte_resolution;
   bool local_file;
   bool check_exists;
   bool autocommit;
@@ -4030,6 +4048,12 @@ public:
     return !create_like() && !create_select();
   }
 
+  bool check_dependencies_in_with_clauses();
+  bool resolve_references_to_cte_in_hanging_cte();
+  bool check_cte_dependencies_and_resolve_references();
+  bool resolve_references_to_cte(TABLE_LIST *tables,
+                                 TABLE_LIST **tables_last);
+
   SELECT_LEX *exclude_last_select();
   bool add_unit_in_brackets(SELECT_LEX *nselect);
   void check_automatic_up(enum sub_select_type type);
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index b16091dbab4..95c04321b4d 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -3506,9 +3506,6 @@ mysql_execute_command(THD *thd)
       thd->get_stmt_da()->opt_clear_warning_info(thd->query_id);
   }
 
-  if (check_dependencies_in_with_clauses(thd->lex->with_clauses_list))
-    DBUG_RETURN(1);
-
 #ifdef HAVE_REPLICATION
   if (unlikely(thd->slave_thread))
   {
@@ -8060,7 +8057,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
     ptr->is_fqtn= TRUE;
     ptr->db= table->db;
   }
-  else if (lex->copy_db_to(&ptr->db))
+  else if (!lex->with_cte_resolution && lex->copy_db_to(&ptr->db))
     DBUG_RETURN(0);
   else
     ptr->is_fqtn= FALSE;
@@ -8075,9 +8072,11 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
     if (ptr->db.length && ptr->db.str != any_db)
       ptr->db.length= my_casedn_str(files_charset_info, (char*) ptr->db.str);
   }
-      
+
   ptr->table_name= table->table;
   ptr->lock_type=   lock_type;
+  ptr->mdl_type= mdl_type;
+  ptr->table_options= table_options;
   ptr->updating=    MY_TEST(table_options & TL_OPTION_UPDATING);
   /* TODO: remove TL_OPTION_FORCE_INDEX as it looks like it's not used */
   ptr->force_index= MY_TEST(table_options & TL_OPTION_FORCE_INDEX);
@@ -8765,8 +8764,10 @@ void st_select_lex::set_lock_for_tables(thr_lock_type lock_type, bool for_update
   {
     tables->lock_type= lock_type;
     tables->updating=  for_update;
-    tables->mdl_request.set_type((lock_type >= TL_WRITE_ALLOW_WRITE) ?
-                                 MDL_SHARED_WRITE : MDL_SHARED_READ);
+
+    if (tables->db.length)
+      tables->mdl_request.set_type((lock_type >= TL_WRITE_ALLOW_WRITE) ?
+                                   MDL_SHARED_WRITE : MDL_SHARED_READ);
   }
   DBUG_VOID_RETURN;
 }
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 4ddb50a651e..ea867e7b63f 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -2359,9 +2359,6 @@ static bool check_prepared_statement(Prepared_statement *stmt)
   if (tables)
     thd->get_stmt_da()->opt_clear_warning_info(thd->query_id);
 
-  if (check_dependencies_in_with_clauses(thd->lex->with_clauses_list))
-    goto error;
-
   if (sql_command_flags[sql_command] & CF_HA_CLOSE)
     mysql_ha_rm_tables(thd, tables);
 
diff --git a/sql/sql_view.cc b/sql/sql_view.cc
index 271e018d2ab..8b398bf3996 100644
--- a/sql/sql_view.cc
+++ b/sql/sql_view.cc
@@ -431,12 +431,6 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
   lex->link_first_table_back(view, link_to_local);
   view->open_type= OT_BASE_ONLY;
 
-  if (check_dependencies_in_with_clauses(lex->with_clauses_list))
-  {
-    res= TRUE;
-    goto err;
-  }
-
   WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL);
 
   /*
@@ -890,6 +884,13 @@ static int mysql_register_view(THD *thd, TABLE_LIST *view,
   LEX *lex= thd->lex;
 
   /*
+    Ensure character set number != 17 (character set = filename) and mbminlen=1
+    because these character sets are not parser friendly, which can give weird
+    sequence in .frm file of view and later give parsing error.
+  */
+  DBUG_ASSERT(thd->charset()->mbminlen == 1 && thd->charset()->number != 17);
+
+  /*
     View definition query -- a SELECT statement that fully defines view. It
     is generated from the Item-tree built from the original (specified by
     the user) query. The idea is that generated query should eliminates all
@@ -1411,9 +1412,6 @@ bool mysql_make_view(THD *thd, TABLE_SHARE *share, TABLE_LIST *table,
     TABLE_LIST *tbl;
     Security_context *security_ctx= 0;
 
-    if (check_dependencies_in_with_clauses(thd->lex->with_clauses_list))
-      goto err;
-
     /*
       Check rights to run commands (ANALYZE SELECT, EXPLAIN SELECT &
       SHOW CREATE) which show underlying tables.
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index b26e2ddbf1b..3f46f0bb9d7 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2020, MariaDB
+   Copyright (c) 2010, 2021, MariaDB
 
    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
@@ -839,6 +839,7 @@ Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
   class sp_head *sphead;
   class sp_name *spname;
   class sp_variable *spvar;
+  class With_element_head *with_element_head;
   class With_clause *with_clause;
   class Virtual_column_info *virtual_column;
 
@@ -2207,7 +2208,7 @@ END_OF_INPUT
 
 %type <with_clause> opt_with_clause with_clause
 
-%type <lex_str_ptr> query_name
+%type <with_element_head> with_element_head
 
 %type <lex_str_list> opt_with_column_list
 
@@ -3345,7 +3346,11 @@ call:
             if (unlikely(Lex->call_statement_start(thd, $2)))
               MYSQL_YYABORT;
           }
-          opt_sp_cparam_list {}
+          opt_sp_cparam_list
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         ;
 
 /* CALL parameters */
@@ -4227,6 +4232,8 @@ sp_proc_stmt_return:
           {
             LEX *lex= Lex;
             sp_head *sp= lex->sphead;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             if (unlikely(sp->m_handler->add_instr_freturn(thd, sp, lex->spcont,
                                                           $3, lex)) ||
                 unlikely(sp->restore_lex(thd)))
@@ -4236,6 +4243,8 @@ sp_proc_stmt_return:
           {
             LEX *lex= Lex;
             sp_head *sp= lex->sphead;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             if (unlikely(sp->m_handler->add_instr_preturn(thd, sp,
                                                                lex->spcont)))
               MYSQL_YYABORT;
@@ -5343,12 +5352,16 @@ create_select_query_expression:
           { 
             Select->set_braces(0);
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
           union_clause
         | opt_with_clause SELECT_SYM create_select_part2 
           create_select_part3_union_not_ready create_select_part4
           {
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         | '(' create_select_query_specification ')'
         | '(' create_select_query_specification ')'
@@ -6097,6 +6110,8 @@ create_select_query_specification:
           create_select_part4
           {
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -9205,6 +9220,8 @@ select:
             LEX *lex= Lex;
             lex->sql_command= SQLCOM_SELECT;
             lex->current_select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -13234,6 +13251,8 @@ do:
           expr_list
           {
             Lex->insert_list= $3;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -13462,6 +13481,8 @@ insert:
           }
           insert_field_spec opt_insert_update
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
         ;
@@ -13481,6 +13502,8 @@ replace:
           }
           insert_field_spec
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
         ;
@@ -13729,7 +13752,11 @@ update:
             */
             slex->set_lock_for_tables($3, slex->table_list.elements == 1);
           }
-          opt_where_clause opt_order_clause delete_limit_clause {}
+          opt_where_clause opt_order_clause delete_limit_clause
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         ;
 
 update_list:
@@ -13844,6 +13871,8 @@ single_multi:
           {
             if (unlikely(multi_delete_set_locks_and_link_aux_tables(Lex)))
               MYSQL_YYABORT;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -14870,6 +14899,8 @@ load:
           opt_field_term opt_line_term opt_ignore_lines opt_field_or_var_spec
           opt_load_data_set_spec
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
           ;
@@ -15287,6 +15318,8 @@ with_clause:
              if (unlikely(with_clause == NULL))
                MYSQL_YYABORT;
              Lex->derived_tables|= DERIVED_WITH;
+             Lex->with_cte_resolution= true;
+             Lex->with_cte_resolution= true;
              Lex->curr_with_clause= with_clause;
              with_clause->add_to_list(Lex->with_clauses_list_last_next);
           }
@@ -15311,7 +15344,7 @@ with_list:
 
 
 with_list_element:
-	  query_name
+          with_element_head
 	  opt_with_column_list 
           {
             $2= new List<LEX_CSTRING> (Lex->with_column_list);
@@ -15332,6 +15365,7 @@ with_list_element:
             if (elem->set_unparsed_spec(thd, spec_start, $8,
                                         spec_start - query_start))
               MYSQL_YYABORT;
+            elem->set_tables_end_pos(lex->query_tables_last);
 	  }
 	;
 
@@ -15358,12 +15392,17 @@ with_column_list:
         ;
 
 
-query_name: 
+with_element_head:
           ident
           {
-            $$= (LEX_CSTRING *) thd->memdup(&$1, sizeof(LEX_CSTRING));
+            LEX_CSTRING *name=
+              (LEX_CSTRING *) thd->memdup(&$1, sizeof(LEX_CSTRING));
             if (unlikely($$ == NULL))
               MYSQL_YYABORT;
+            $$= new (thd->mem_root) With_element_head(name);
+            if ($$ == NULL)
+              MYSQL_YYABORT;
+            $$->tables_pos.set_start_pos(Lex->query_tables_last);
           }
         ;
 
@@ -16308,7 +16347,10 @@ set:
             sp_create_assignment_lex(thd, yychar == YYEMPTY);
           }
           start_option_value_list
-          {}
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         | SET STATEMENT_SYM
           {
             Lex->set_stmt_init();
@@ -17825,6 +17867,9 @@ view_select:
             lex->create_view->check= $4;
             lex->parsing_options.allows_variable= TRUE;
             lex->current_select->set_with_clause($2);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+
           }
         ;
 
diff --git a/sql/sql_yacc_ora.yy b/sql/sql_yacc_ora.yy
index 4af034db921..f74af1008c4 100644
--- a/sql/sql_yacc_ora.yy
+++ b/sql/sql_yacc_ora.yy
@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2020, MariaDB
+   Copyright (c) 2010, 2021, MariaDB
 
    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
@@ -232,6 +232,7 @@ void ORAerror(THD *thd, const char *s)
   class sp_head *sphead;
   class sp_name *spname;
   class sp_variable *spvar;
+  class With_element_head *with_element_head;
   class With_clause *with_clause;
   class Virtual_column_info *virtual_column;
 
@@ -1628,7 +1629,7 @@ END_OF_INPUT
 
 %type <with_clause> opt_with_clause with_clause
 
-%type <lex_str_ptr> query_name
+%type <with_element_head> with_element_head
 
 %type <lex_str_list> opt_with_column_list
 
@@ -2999,7 +3000,11 @@ call:
             if (unlikely(Lex->call_statement_start(thd, $2)))
               MYSQL_YYABORT;
           }
-          opt_sp_cparam_list {}
+          opt_sp_cparam_list
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         ;
 
 /* CALL parameters */
@@ -3986,6 +3991,8 @@ sp_proc_stmt_return:
           {
             LEX *lex= Lex;
             sp_head *sp= lex->sphead;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             if (unlikely(sp->m_handler->add_instr_freturn(thd, sp, lex->spcont,
                                                           $3, lex)) ||
                 unlikely(sp->restore_lex(thd)))
@@ -3995,6 +4002,8 @@ sp_proc_stmt_return:
           {
             LEX *lex= Lex;
             sp_head *sp= lex->sphead;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             if (unlikely(sp->m_handler->add_instr_preturn(thd, sp,
                                                                lex->spcont)))
               MYSQL_YYABORT;
@@ -5185,12 +5194,16 @@ create_select_query_expression:
           { 
             Select->set_braces(0);
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
           union_clause
         | opt_with_clause SELECT_SYM create_select_part2 
           create_select_part3_union_not_ready create_select_part4
           {
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         | '(' create_select_query_specification ')'
         | '(' create_select_query_specification ')'
@@ -5939,6 +5952,8 @@ create_select_query_specification:
           create_select_part4
           {
             Select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -9135,6 +9150,8 @@ select:
             LEX *lex= Lex;
             lex->sql_command= SQLCOM_SELECT;
             lex->current_select->set_with_clause($1);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -13172,6 +13189,8 @@ do:
           expr_list
           {
             Lex->insert_list= $3;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -13416,6 +13435,8 @@ insert:
           }
           insert_field_spec opt_insert_update
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
         ;
@@ -13435,6 +13456,8 @@ replace:
           }
           insert_field_spec
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
         ;
@@ -13683,7 +13706,11 @@ update:
             */
             slex->set_lock_for_tables($3, slex->table_list.elements == 1);
           }
-          opt_where_clause opt_order_clause delete_limit_clause {}
+          opt_where_clause opt_order_clause delete_limit_clause
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         ;
 
 update_list:
@@ -13798,6 +13825,8 @@ single_multi:
           {
             if (unlikely(multi_delete_set_locks_and_link_aux_tables(Lex)))
               MYSQL_YYABORT;
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
           }
         ;
 
@@ -14830,6 +14859,8 @@ load:
           opt_field_term opt_line_term opt_ignore_lines opt_field_or_var_spec
           opt_load_data_set_spec
           {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
             Lex->mark_first_table_as_inserting();
           }
           ;
@@ -15247,6 +15278,8 @@ with_clause:
              if (unlikely(with_clause == NULL))
                MYSQL_YYABORT;
              Lex->derived_tables|= DERIVED_WITH;
+             Lex->with_cte_resolution= true;
+             Lex->with_cte_resolution= true;
              Lex->curr_with_clause= with_clause;
              with_clause->add_to_list(Lex->with_clauses_list_last_next);
           }
@@ -15271,7 +15304,7 @@ with_list:
 
 
 with_list_element:
-	  query_name
+          with_element_head
 	  opt_with_column_list 
           {
             $2= new List<LEX_CSTRING> (Lex->with_column_list);
@@ -15292,6 +15325,7 @@ with_list_element:
             if (elem->set_unparsed_spec(thd, spec_start, $8,
                                         spec_start - query_start))
               MYSQL_YYABORT;
+            elem->set_tables_end_pos(lex->query_tables_last);
 	  }
 	;
 
@@ -15318,12 +15352,17 @@ with_column_list:
         ;
 
 
-query_name: 
+with_element_head:
           ident
           {
-            $$= (LEX_CSTRING *) thd->memdup(&$1, sizeof(LEX_CSTRING));
+            LEX_CSTRING *name=
+              (LEX_CSTRING *) thd->memdup(&$1, sizeof(LEX_CSTRING));
             if (unlikely($$ == NULL))
               MYSQL_YYABORT;
+            $$= new (thd->mem_root) With_element_head(name);
+            if ($$ == NULL)
+              MYSQL_YYABORT;
+            $$->tables_pos.set_start_pos(Lex->query_tables_last);
           }
         ;
 
@@ -16305,7 +16344,10 @@ set:
             sp_create_assignment_lex(thd, yychar == YYEMPTY);
           }
           start_option_value_list
-          {}
+          {
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+          }
         | SET STATEMENT_SYM
           {
             Lex->set_stmt_init();
@@ -17873,6 +17915,9 @@ view_select:
             lex->create_view->check= $4;
             lex->parsing_options.allows_variable= TRUE;
             lex->current_select->set_with_clause($2);
+            if (Lex->check_cte_dependencies_and_resolve_references())
+              MYSQL_YYABORT;
+
           }
         ;
 
diff --git a/sql/table.h b/sql/table.h
index 6a4c6eb2a03..325d4030f4e 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -2056,6 +2056,29 @@ struct vers_select_conds_t
 
 struct LEX;
 class Index_hint;
+
+/*
+  @struct TABLE_CHAIN
+  @brief Subchain of global chain of table references
+
+  The structure contains a pointer to the address of the next_global
+  pointer to the first TABLE_LIST objectof the subchain and the address
+  of the next_global pointer to the element right after the last
+  TABLE_LIST object of the subchain.  For an empty subchain both pointers
+  have the same value.
+*/
+
+struct TABLE_CHAIN
+{
+  TABLE_CHAIN() {}
+
+  TABLE_LIST **start_pos;
+  TABLE_LIST ** end_pos;
+
+  void set_start_pos(TABLE_LIST **pos) { start_pos= pos; }
+  void set_end_pos(TABLE_LIST **pos) { end_pos= pos; }
+};
+
 struct TABLE_LIST
 {
   TABLE_LIST() {}                          /* Remove gcc warning */
@@ -2380,6 +2403,20 @@ struct TABLE_LIST
   /* call back function for asking handler about caching in query cache */
   qc_engine_callback callback_func;
   thr_lock_type lock_type;
+
+  /*
+    Two fields below are set during parsing this table reference in the cases
+    when the table reference can be potentially a reference to a CTE table.
+    In this cases the fact that the reference is a reference to a CTE or not
+    will be ascertained at the very end of parsing of the query when referencies
+    to CTE are resolved. For references to CTE and to derived tables no mdl
+    requests are needed while for other table references they are. If a request
+    is possibly postponed the info that allows to issue this request must be
+    saved in 'mdl_type' and 'table_options'.
+  */
+  enum_mdl_type mdl_type;
+  ulong         table_options;
+
   uint		outer_join;		/* Which join type */
   uint		shared;			/* Used in multi-upd */
   bool          updatable;		/* VIEW/TABLE can be updated now */