BBF（Best Bin First）是一种改进的k-d树最近邻查询算法。从前两篇标准的k-d树查询过程可以看出其搜索过程中的“回溯”是由“查询路径”来决定的，并没有考虑查询路径上数据点本身的一些性质。BBF的查询思路就是将“查询路径”上的节点进行排序，如按各自分割超平面（称为Bin）与查询点的距离排序。回溯检查总是从优先级最高的（Best Bin）的树节点开始。另外BBF还设置了一个运行超时限制，当优先级队列中的所有节点都经过检查或者超出时间限制时，算法返回当前找到的最好结果作为近似的最近邻。采用了best-bin-first search方法就可以将k-d树扩展到高维数据集上。
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001794s ]
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:0.083188s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.002419s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.002042s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.002050s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003504s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.002074s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003167s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014149s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.005422s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 251368 [ RunTime:0.001287s ]
