红黑树是一种自平衡二叉查找树，是在计算机科学中用到的一种数据结构，典型的用途是实现关联数组。它是在1972年由Rudolf Bayer发明的，他称之为"对称二叉B树"，它现代的名字是在 Leo J. Guibas 和 Robert Sedgewick 于1978年写的一篇论文中获得的。它是复杂的，但它的操作有着良好的最坏情况运行时间，并且在实践中是高效的： 它可以在O(log n)时间内做查找，插入和删除，这里的n 是树中元素的数目。
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001957s ]
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:0.119794s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001513s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.002384s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001870s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.004680s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001358s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003424s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015092s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001432s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 323945 [ RunTime:0.001272s ]
