You have to specifyAVG_ROW_LENGTHonly for tables withBLOBorTEXTcolumns; in this case, MySQL cannot optimize the space required based only on the number of rows. To change the default size limit forMyISAMtables, set themyisam_data_pointer_size, which sets the number of bytes used for inter...
You have to specifyAVG_ROW_LENGTHonly for tables withBLOBorTEXTcolumns; in this case, MySQL cannot optimize the space required based only on the number of rows. To change the default size limit forMyISAMtables, set themyisam_data_pointer_size, which sets the number of bytes used for inter...
一、发现问题 在一次准备处理历史数据sql时,出现这么一个问题:You can't specify target table '表名' for update in FROM clause,大致的意思就是:不能在同一张表中先select再update。 在此进行一下复盘沉淀,使用测试sql复现当时的场景(mysql是8版本),准备测试数据: CREATE TABLE `student` ( `id` int NOT ...
1、进入Mysql命令行,输入show variables like “innodb_buffer_pool%”; 这里缓冲池大小默认是8M(8 ∗ \ast∗ 1024 ∗ \ast∗ 1024 = 8388608),刚好等于innodb_buffer_pool_instances ∗ \ast∗ innodb_buffer_pool_chunk_size的积。 2、修改缓冲池大小 下面将缓冲池大小设为1G(1 ∗ \ast∗ 1...
事情的原因是:我执行了一个 语句的SQL将一个很大的文件导入到我的MySQL数据库中,执行了一段时间后报错“The total number of locks exceeds the lock table size”。 首先使用命令 查看MySQL的存储引擎: 可以看到InnoDB是MySQL的默认
在MySQL数据库中,有时会遇到一个特定的错误,即ERROR 1109 (42S02): Unknown table 'INNODB_SYS_TABLES' in information_schema。这个错误通常意味着InnoDB存储引擎的某些内部表在information_schema数据库中无法找到。这种情况可能由多种原因引起,包括数据库损坏、InnoDB引擎的不兼容版本或错误的配置等。 错误原因: 数据...
我们的mysql这两个参数为: tmp_table_size 33554432 (33.5M) max_heap_table_size 16777216 (16.7M) 比较小。 建议增加到上百M。我们的内存应该够吧。 另外join_buffer_size(影响 表之间join性能的缓存)为131072 (131K)较小,可以增加一点。 [root@mail ~]# vi /etc/my.cnf ...
mysql>ALTERTABLEsbtest1ADDCOLUMNpad6varchar(4990),ALGORITHM=INSTANT;ERROR1118(42000):Row size too large.The maximum row sizeforthe used table type,not counting BLOBs,is65535.This includes storage overhead,check the manual.You have to change some columns toTEXTor BLOBs ...
anywhere near the 4G mem size. By the way, I was able to create a MyISAM table with 5 mil rows using the same my.cnf file without a problem. I don't want to use a disk based table because we need to do on average 60 updates/sec. and it would kill the HDD in no time. ...
MySQL 工作台 语法 以下为创建MySQL数据表的SQL通用语法: CREATE TABLE [IF NOT EXISTS] table_name( column_definition1, column_definition2, …….., table_constraints ); 也可简写为: CREATE TABLE table_name (column_name column_type); 上述语法的参...