数据库升级到MySQL 8.0之后,业务代码连接数据库失败。报错信息为“java.sql.SQLException: Cannot create PoolableConnectionFactory (Could not create connection to database server.)” 代码语言:javascript 复制 getconnetion from pool error:ConnectionInfo{jdbcUrl='jdbc:mysql://9.9.9.9:3306/db?useSSL=false&...
log_slow_admin_statements = 1 #开启不是查询的慢sql(include ALTER TABLE, ANALYZE TABLE, CHECK TABLE, CREATE INDEX, DROP INDEX, OPTIMIZE TABLE, and REPAIR TABLE.);默认关闭# min_examined_row_limit = 100 #查询少于该指定的行 不写到慢日志中;默认0# log_slow_slave_statements = 1 #记录从服务...
='1' 的行数据时,因没有被加行锁,会立即返回数据SELECT*FROMtest.tb_studentWHERE1=1andid='1'LIMIT1FORUPDATE;-- 无法获取到锁-- 在 会话窗口1 先开启的事务没有 commit 或 rollback 之前,查询 id='1' 的行数据时,将始终处于等待状态,不会返回数据-- SELECT * FROM test.tb_student WHERE 1=1 a...
open_files_limit=65535全局静态参数,默认值5000。用于mysqld可打开的文件描述符的数量。如果无法分配请求的文件描述符数量,mysqld将警告写入错误日志,mysqld报错Too many open files,应该尝试增大该值。当open_files_limit没有被配置的时候,比较max_connections*5和ulimit-n的值,哪个大用哪个,当open_file_limit被配...
/*案例1*/ use itcast; create table control_test( id int primary key auto_increment comment '主键', name varchar(10) not null unique comment '姓名', age int check(age>0 and age<=120) comment '年龄', status char(1) default '1' comment '状态', gender char(1) comment '性别' ); ...
AND r.check_content_id='0' ) ORDER BY update_time DESC,check_content_id LIMIT 0, 15 (3)把这条语句用前面提到show profile进行分析: 可以看到有两Sending data占用时间都挺高的,花费时间也高,其实这语句用了联合查询,我们可以把SQL语句拆分了继续分析(复杂语句都是由简单语句组成,比较不爽的是有时候分...
安装mysql卡在checkrequirements 安装mysql时check报错 全文很长, 建议先到github 下载代码, 在这里: https://github.com/xiaofeipapa/python_example/tree/master/examplegithub.com 满满的都是代码, 下载下来看代码岂不美哉. 初始化准备 安装pymysql 包
flags: List of connection flags to use other than the default ones. It is also possible to blacklist default ones. For more information, checkConnection Flags. ssl: object with ssl parameters or a string containing name of ssl profile. SeeSSL options. ...
dontCheckOnDuplicateKeyUpdateInSQL false 5.1.32 elideSetAutoCommits false 3.1.3 enableEscapeProcessing true 6.0.1 enableQueryTimeouts true 5.0.6 largeRowSizeThreshold 2048 5.1.1 readOnlyPropagatesToServer true 5.1.35 rewriteBatchedStatements false 3.1.13 useReadAheadInput true 3.1.5 14 调试/分析属...
The number of outstanding connection requests MySQL can have. This comes into play when the main MySQL thread gets very many connection requests in a very short time. It then takes some time (although very little) for the main thread to check the connection and start a new thread. The ...