Failed to execute the SQL query

 select  UNIX_TIMESTAMP( ifnull(i.pubdate, i.added)) as ts_,  year( ifnull(i.pubdate, i.added)) as y_,  month( ifnull(i.pubdate, i.added)) as m_,  dayofmonth( ifnull(i.pubdate, i.added)) as d_,  count(*) as cnt_  from  ipo__item i  where  UNIX_TIMESTAMP(ifnull(i.pubdate, i.added)) > 1538172000  and not(i.unread & 4)  group by y_,m_,d_  order by ts_ asc limit 4

Error 2013: Lost connection to server during query