ver 3.0.9 very slow

Hi

Why is the same delete query being performed every time?

DELETE c1 FROM wp_moove_activity_log c1
        INNER JOIN
    wp_moove_activity_log c2 
WHERE
    c1.post_id > c2.post_id
    AND c1.campaign_id = c2.campaign_id
    AND c1.visit_date = c2.visit_date
    AND c1.referer = c2.referer
    AND c1.status = c2.status;

my database is

select count(*) FROM wp_moove_activity_log c1
        INNER JOIN
    wp_moove_activity_log c2 
WHERE
    c1.post_id > c2.post_id
    AND c1.campaign_id = c2.campaign_id
    AND c1.visit_date = c2.visit_date
    AND c1.referer = c2.referer
    AND c1.status = c2.status;

count => 0

Every time I enter the plugin after upgrading to 3.0.9, it is too slow.