深入理解计算机系统（computer system：a programmer s perpective)是一本非常经典的教材，国内外很多大学都采用此教材讲授ICS课程（introduction to computer system) 本代码是该书配套的一个实验的实现，（代码优化，图形学相关）得了满分哦！
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001737s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.128213s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.002094s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001973s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.002035s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003234s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000954s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003794s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015907s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001261s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 581383 [ RunTime:0.011964s ]
