估算是什么？怎样估算？

页面:/news/view-490656/ | 耗时:0.3258 s | 内存:1.89 MB | 查询:4 | 缓存读取:4 写入:0 | 加载文件:23
select * from tbl_Articles WHERE ArticleID=490656 LIMIT 0,1
select * from tbl_Articles_data WHERE ArticleID=490656 LIMIT 0,1
select * from tbl_Articles_sphinx where id=490656 LIMIT 0,1
SELECT ArticleID,Title FROM tbl_Articles WHERE ArticleID IN(1598120,1806220,2350029,2008268,3258591,2366879,1078015,769098,2297655,1161068,570902,2755673,836631,1748541,2142561,878875,3407094,385361,385243,377127,1506644,1121575,2862804,391284,1016720,3157215,2193973,734987,556697,1118251) ORDER BY field (ArticleID,1598120,1806220,2350029,2008268,3258591,2366879,1078015,769098,2297655,1161068,570902,2755673,836631,1748541,2142561,878875,3407094,385361,385243,377127,1506644,1121575,2862804,391284,1016720,3157215,2193973,734987,556697,1118251)