SELECT
	`v_yy_yb021_ext`.typeid,
	`v_yy_yb021_ext`.title,
	`v_yy_yb021_ext`.orgid AS jgid,
	`v_yy_yb021_ext`.orgname AS jgmc,
	`v_yy_yb021_ext`.humanname AS author,
	`v_yy_yb021_ext`.ctime AS time,
	`v_yy_yb021_ext`.seq AS id,
	`v_yy_yb021_ext`.typename AS type
FROM `human_famous`
LEFT JOIN `v_yy_yb021_ext`
ON `human_famous`.`hycode` = `v_yy_yb021_ext`.`hycode`
AND `human_famous`.`humanid` = `v_yy_yb021_ext`.`humanid`

WHERE `v_yy_yb021_ext`.`isvalid` = 1
AND `v_yy_yb021_ext`.`declaredate` >= '2016-10-06'
ORDER BY `ctime` DESC
LIMIT 0,10;

不加排序的话，执行时间为5s，加了排序之后，需要60s的时间。
where和orderby的字段都有索引。
EXPLAIN 输出如下：
1	SIMPLE	human_famous		index	PRIMARY	PRIMARY	                                                132		                       2701	100	Using index; Using temporary; Using filesort
1	SIMPLE	v_yy_yb021_ext		ref	hycode,declaredate,humanid,hycode_humanid,humanid_ctime	hycode	67	vis_db.human_famous.hycode	2	2.5	Using where