BIRCH（Balanced Iterative Reducing and Clustering using Hierarchies）天生就是为处理超大规模（至少要让你的内存容不下）的数据集而设计的，它可以在任何给定的内存下运行。BIRCH算法的过程就是要把待分类的数据插入一棵树中，并且原始数据都在叶子节点上。
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.003154s ]
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:0.068943s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.000930s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001079s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.000963s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003101s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000802s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003822s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014939s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001040s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 325322 [ RunTime:0.012643s ]
