• Igor Babaev's avatar
    Fixed bug mdev-585 (LP bug #637962) · 7714739b
    Igor Babaev authored
    If, when executing a query with ORDER BY col LIMIT n, the optimizer chose
    an index-merge scan to access the table containing col while there existed
    an index defined over col then optimizer did not consider the possibility
    of using an alternative range scan by this index to avoid filesort. This
    could cause a performance degradation if the optimizer flag index_merge was
    set up to 'on'.
    7714739b
range_vs_index_merge_innodb.result 63.3 KB