• Igor Babaev's avatar
    MDEV-15575 different results when using CTE and big_tables=1. · 224f7af9
    Igor Babaev authored
    This bug happened due to a defect of the implementation of the handler
    function ha_delete_all_rows() for the ARIA engine.
    The function maria_delete_all_rows() truncated the table, but it didn't
    touch the write cache, so the cache's write offset was not reset.
    In the scenario like in the function st_select_lex_unit::exec_recursive
    when first all records were deleted from the table and then several new
    records were added some metadata became inconsistent with the state of
    the cache. As a result the table scan function could not read records
    at the end of the table.
    The same defect could be found in the implementation of ha_delete_all_rows()
    for the MYISAM engine mi_delete_all_rows().
    
    Additionally made late instantiation for the temporary table used to store
    rows that were used for each new iteration when executing a recursive CTE.
    224f7af9
cte_recursive.result 75.7 KB