用来产生随机数 从产生的随机数序列找下一个
@return 0, HA_ERR_END_OF_FILE, or error number */ UNIV_INTERN int ha_innobase::rnd_next( /*===*/ uchar* buf) /*!< in/out: returns the row in this buffer, in MySQL format */ { int error; DBUG_ENTER("rnd_next"); ha_statistic_increment(&SSV::ha_read_rnd_next_count);...
handler_read_rnd_next 是MySQL 中的一个状态变量,用于衡量在数据文件中读下一行的请求数。当这个值较高时,通常意味着系统正在进行大量的表扫描,而没有有效利用索引。这种情况往往会导致查询性能低下。 2. handler_read_rnd_next 值高的可能原因 索引缺失或不恰当:如果查询的列上没有建立索引,或者索引设计不合理...
4. Handler_read_rnd_next不宜过大,过大的话,代表全表扫描过多,要引起足够的警惕。
用show status like 'Handler_read%';查看你的索引使用情况,Handler_read_rnd_next 很高意味着查询效率低下,说明你要换 一个索引值。然后用show profile看看你的..
将产生的随机数与0x7fffffff按位与运算，而0x7fffffff换成二进制是31个1，由此可知，这句话的作用是将产生的随机数最高位置为0，其它位保持不变。
My Handler_read_rnd_next is very far. The explanation for this variable is: The number of requests to read the next row in the data file. This is high if you are doing a lot of table scans. Generally this suggests that your tables are not properly indexed or that your queries are no...
*/publicKeyPairgetKeyPair(){return_keyPairs[Rnd.nextInt(10)]; } 开发者ID:Zoey76,项目名称:L2J_LoginServer,代码行数:9,代码来源:GameServerTable.java 示例6: getRandomInt ▲点赞 2▼ importcom.l2jserver.util.Rnd;//导入方法依赖的package包/类@OverridepublicintgetRandomInt(){returnRnd.nextInt(...
> Java => rnd.nextInt() > Clojure => (. rnd nextInt) > sugared => (.nextInt rnd) > > > What's the point of the sugared version? It's not any less to type. > It's also incomprehensible to me how it came about. In the middle one ...
Handler_read_rnd_next is 2M at an uptime of 9 hours Handler_read_rnd is 13K at an uptime of 9 hours I know the meaning of these values and the recommendation (...not properly indexed), but I do not know how to track the causer or how to proceed to avoid table scanning. ...