查看max_length_for_sort_data影响的排序行为 要更好的理解max_length_for_sort_data的作用,我们可以对一个表进行排序操作,并观察性能上的变化。 首先,创建一个测试表: CREATETABLEtest_sort(idINTAUTO_INCREMENTPRIMARYKEY,nameVARCHAR(255)); 1. 2. 3. 4. 然后填充一些
步骤1: 查看当前的max_length_for_sort_data值 首先,我们需要查看当前Mysql的max_length_for_sort_data值,可以使用如下的SQL语句: SHOWVARIABLESLIKE'max_length_for_sort_data'; 1. 这条SQL语句会返回类似下面的结果: 步骤2: 计算合适的max_length_for_sort_data值 根据实际情况,我们需要计算合适的max_length_...
mysql有两种文件排序算法(双路排序和单路排序),如果需要排序的列的总大小加上order by列的大小超过了 max_length_for_sort_data定义的字节,mysql就会使用双路排序,当任何需要的列甚至不是用order by的列(text.blob的时候),也会使用双路排序,(可以使用substtring() 把这些列转化为可以单路排序的列)。 可以通过...
Bug #5394 max_sort_length does not invalidate queries in the query cache Submitted: 3 Sep 2004 17:00Modified: 10 Sep 2004 19:26 Reporter: Sergei Golubchik Email Updates: Status: Closed Impact on me: None Category: MySQL ServerSeverity: S3 (Non-critical) Version: 4.0OS: Assigned to:...
| max_sort_length | 1024 | | max_sp_recursion_depth | 0 | | max_tmp_tables | 32 | | max_user_connections | 0 | | max_write_lock_count | 4294967295 | +---+---+ 19 rows in set (0.01 sec) mysql> set max_allowed_packet = 8388608...
mysql数据太大导表出错-Specified key was too long; max key length is 767 bytes 修改下面: setglobalmax_allowed_packet=67108864000; SET GLOBAL max_sort_length=20480000000
环境排查无问题,除PigCodeGenApplication外其他模块启动正常,pig_config.sql执行正常 报错内容: [SQL] Query pig start [ERR] 1071 - Specified key was too long; max key length is 1000 bytes [ERR] DROP DATABASE IF EXISTSpig; CREATE DATABASEpigDEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_general...
max_length_for_sort_data temptable_max_ram When is an Internal Temporary Table Created on Disk? How to Avoid Creating the Internal Temporary Table on Disk? Use MySQL 8.0 and the TempTable Storage Engine Rewrite Queries to Include Less Data Avoid BLOB and TEXT Columns Do not Make VARCHAR and...
max_allowed_packet 如果不设置,默认值在不同的 MySQL 版本表现不同,有的版本默认1M,有的版本默认4M。 vi /etc/my.cnf 在mysqld节点下增加:128M或者256M,最大1G [mysqld] max_allowed_packet = 128M 2.修改完成后,重启服务。 service mysql restart...
max_sort_length = 32M max_connections = 160 table_cache = 512 thread_concurrency = 16 And, finally, the beginning of the output we get: law@chinacat> testmaxpack max_allowed_packet: 1073741824 The record I'm about to get is 7991 characters. ...