Failed to execute the SQL query

select f.id, f.name, count(*) as cnt  from  rss_item  i  inner join  rss_channels  c on c.id = i.cid  inner join  rss_folders  f on f.id = c.parent  where i.unread & 1 and not(i.unread & 8) and not(unread & 4)  and not(c.mode & 8)  group by f.id

Error 1104: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay