• Monty's avatar
    MDEV-30080 Wrong result with LEFT JOINs involving constant tables · 0595dd0f
    Monty authored
    The reason things fails in 10.5 and above is that test_quick_select()
    returns -1 (impossible range) for empty tables if there are any
    conditions attached.
    
    This didn't happen in 10.4 as the cost for a range was more than for
    a table scan with 0 rows and get_key_scan_params() did not create any
    range plans and thus did not mark the range as impossible.
    
    The code that checked the 'impossible range' conditions did not take
    into account all cases of LEFT JOIN usage.
    
    Adding an extra check if the table is used with an ON condition in case
    of 'impossible range' fixes the issue.
    0595dd0f
join.result 129 KB