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10 total results found

Deadlock

MySQL Troubleshooting

mysql 5.7 查看事务的阻塞关系 SELECT r.trx_id waiting_trx_id, r.trx_mysql_thread_id waiting_thread, r.trx_query waiting_query, b.trx_id blocking_trx_id, b.trx_mysql_thread_id blocking_thread, b.trx_query blocking_query FROM information_sch...

troubleshooting
deadlock
mysql
database

Kylin OOM

MySQL Troubleshooting

解决Kylin V10 下 MySQL 容器内存占用异常的问题,参考文档https://zhuanlan.zhihu.com/p/679582049?utm_medium=social&utm_psn=1837658450517184512&utm_source=wechat_session ulimit -n 1048576 && ulimit -a >/dev/null && ulimit -n #!/bin/bash set -eo pipefail shopt -s nullglob --- ## l...

ulimit
oom
kylin
mysql
database

binlog

MySQL Quick Start

Show Variables SHOW VARIABLES LIKE 'log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin | ON | +---------------+-------+ 1 row in set (0.01 sec) binlog Path /var/lib/mysql/binglog.index /var/lib/mysql...

binlog
mysql

MyDumper

MySQL Tools

https://mydumper.github.io/mydumper/docs/html/index.html Installation macOS brew install mydumper

mydumper
mysql
database

Commands

MySQL Quick Start

Config Path mysql --help | grep -B 1 etc/my.cnf Default options are read from the following files in the given order: /etc/my.cnf /etc/mysql/my.cnf /opt/homebrew/etc/my.cnf ~/.my.cnf mysqldump With DB Creation User --databases mysqldump -hlocalhost -uroot -...

database
commands
mysqldump
mysql

Quick Count

MySQL Quick Start

使用最小覆盖索引 针对 InnoDB 表(几十万到几百万行)快速统计行数,可以有几个方法。下面按实用性和效率排序: 选择最窄的索引列(最好是整型或短列)进行扫描,不访问表数据页。 假设你有一个 updated_at 的索引: SELECT COUNT(updated_at) FROM cert; 优化器会用覆盖索引,只扫描索引页,比全表扫描快很多。 如果想强制使用: SELECT COUNT(updated_at) FROM cert USE INDEX (idx_updated_at); 注意:不...

count
mysql
database

pt-table-checksum

MySQL Tools

Installation apt-get -y install percona-toolkit Priviledges 目标库 GRANT SELECT ON foo.* TO 'pttable'@'%'; 校验结果库 GRANT CREATE, INSERT, UPDATE, DELETE ON percona.* TO 'pttable'@'%'; 其它权限 GRANT PROCESS, REPLICATION CLIENT, REPLICATION SLAVE ON *.* TO 'pttable'@...

pt-table
mysql
database

pt-table-sync

MySQL Tools

Usage Print Diff pt-table-sync \ --print \ --chunk-size=1000 \ h=master_host,P=3306,u=root,p=123456,D=mydb,t=mytable \ h=slave_host,P=3306,u=root,p=123456 Execute Diff pt-table-sync \ --execute \ --chunk-size=1000 \ h=master_host,P=3306,u=root,...

pt-table
mysql
database

Localhost/127/UnixSocket

MySQL Troubleshooting

question这是 MySQL 客户端的默认行为!当你在配置文件中指定 host=localhost 时,MySQL 客户端会自动尝试使用 Unix socket 连接,但如果 Unix socket 不可用或连接失败,它就会回退到 TCP 连接,并将 localhost 解析为 127.0.0.1。

troubleshooting
mysql
database

Installation

MySQL Quick Start

MySQL Client 到 Oracle 官方 MySQL APT repo 下载配置包(最新版在 2025 之前是 0.8.33 这一支): wget https://dev.mysql.com/get/mysql-apt-config_0.8.33-1_all.deb dpkg -i mysql-apt-config_0.8.33-1_all.deb 安装过程中会弹出一个选择界面: 选 MySQL Server & Cluster (Currently selected: mysql-x.x) 里面会...

installation
mysql