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    f4a0af07
    Fix for bug #16672723 "CAN'T FIND TEMPORARY TABLE". · f4a0af07
    Dmitry Lenev authored
    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.
    f4a0af07
    Fix for bug #16672723 "CAN'T FIND TEMPORARY TABLE".
    Dmitry Lenev authored
    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.
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