• Dmitry Lenev's avatar
    MDEV-9084 Calling a stored function from a nested select from temporary table... · e4978d26
    Dmitry Lenev authored
    MDEV-9084 Calling a stored function from a nested select from temporary table causes unpredictable behavior
    
    Cherry-pick: f4a0af070ce49abae60040f6f32e1074309c27fb
    Author: Dmitry Lenev <dmitry.lenev@oracle.com>
    Date:   Mon Jul 25 16:06:52 2016 +0300
    
      Fix for bug #16672723 "CAN'T FIND TEMPORARY TABLE".
    
      Attempt to execute prepared CREATE TABLE SELECT statement which used
      temporary table in the subquery in FROM clause and stored function
      failed with unwarranted ER_NO_SUCH_TABLE error. The same happened
      when such statement was used in stored procedure and this procedure
      was re-executed.
    
      The problem occurred because execution of such prepared statement/its
      re-execution as part of stored procedure incorrectly set
      Query_table_list::query_tables_own_last marker, indicating the last
      table which is directly used by statement. As result temporary table
      used in the subquery was treated as indirectly used/belonging to
      prelocking list and was not pre-opened by open_temporary_tables()
      call before statement execution. Thus causing ER_NO_SUCH_TABLE errors
      since our code assumes that temporary tables need to be correctly
      pre-opened before statement execution.
    
      This problem became visible only in version 5.6 after patches related to
      bug 11746602/27480 "EXTEND CREATE TEMPORARY TABLES PRIVILEGE TO ALLOW
      TEMP TABLE OPERATIONS" since they have introduced pre-opening of temporary
      tables for statements.
    
      Incorrect setting of Query_table_list::query_tables_own_last happened
      in LEX::first_lists_tables_same() method which is called by CREATE TABLE
      SELECT implementation as part of LEX::unlink_first_table(), which temporary
      excludes table list element for table being created from the query table
      list before handling SELECT part.
    
      LEX::first_lists_tables_same() tries to ensure that global table list of
      the statement starts with the first table list element from the first
      statement select. To do this it moves such table list element to the head
      of the global table list. If this table happens to be last directly-used
      table for the statement, query_tables_own_last marker is pointing to it.
      Since this marker was not updated when table list element was moved we
      ended up with all tables except the first table separated by it as if
      they were not directly used by statement (i.e. belonged to prelocked
      tables list).
    
      This fix changes code of LEX::first_lists_tables_same() to update
      query_tables_own_last marker in cases when it points to the table
      being moved. It is set to the table which precedes table being moved
      in this case.
    e4978d26
sp-prelocking.result 7.42 KB