MySQL is adding more tools to monitor its internals with every new release, but one thing it still lacks is a way to find out who is locking what, and therefore which transactions block which other ones. This is such a vital feature that I’m consider…

当前mysql版本:5.6.21 一.背景 在mysql处理死锁问题时,由于show engine innodb status输出来的死锁日志无任务事务上下文,并不能很好地诊断相关事务所持有的所有锁信息,包括:锁个数.锁类型等. 于是,需要能查看到更详细的事务锁占用情况. 二.INNODB监控机制(InnoDB Monitors) mysql提供一套INNODB监控机制,用于周期性(每15钞)输出INNODB运行相关状态(INNODB运行状态.表空间状态.表状态等)到mysqld服务标准错误输出…

14.3 InnoDB Transaction Model and Locking 14.3.1 InnoDB Lock Modes 14.3.2 InnoDB Record, Gap, and Next-Key Locks 14.3.3 Avoiding the Phantom Problem Using Next-Key Locking 14.3.4 Consistent Nonlocking Reads 14.3.5 Locking Reads (SELECT ... FOR UPDATE…

小结: 1.注意使用限制 Locking reads are only possible when autocommit is disabled (either by beginning transaction with START TRANSACTION or by setting autocommit to 0. SELECT ... FOR UPDATE or SELECT ... FOR SHARE MySQL :: MySQL 8.0 Reference Manual :: 15.7.…

15. 其他存储引擎 15. 其他存储引擎 15.1 设置存储引擎 15.2 MyISAM存储引擎 15.2.1 MyISAM启动选项 15.2.2 Key的空间要求 15.2.3 MyISAM表存储格式 15.2.3.1 静态表特性 15.2.3.2 动态表特性 15.2.3.3 压缩表特性 15.2.4 MyISAM表问题 15.2.4.1 MyISAM表损坏 15.2.4.2 表没有被正确关闭 15.3 MEMORY存储引擎 15.3.1 性能特点 15.3.2 MEMORY表的物理特性…

hbase.rootdir 这个目录是region server的共享目录,用来持久化HBase.URL需要是'完全正确'的,还要包含文件系统的scheme.例如,要表示hdfs中的'/hbase'目录,namenode 运行在namenode.example.org的9090端口.则需要设置为hdfs://namenode.example.org:9000/hbase.默认情况下HBase是写到/tmp的.不改这个配置,数据会在重启的时候丢失. 默认: file:///tmp/hbase-${…

引用自:http://rusanu.com/2013/08/01/understanding-how-sql-server-executes-a-query/ Understanding how SQL Server executes a query August 1st, 2013 If you are a developer writing applications that use SQL Server and you are wondering what exactly happens…

备份分类 物理和逻辑备份 物理备份直接拷贝数据库目录和文件,适合数据量大.重要且需要在出现问题时快速恢复的数据库 逻辑备份保存信息包括逻辑数据库结构(数据库表的创建脚本)和内容(插入语句或者分隔符平面文件),适合数据量小或异构数据库数据迁移 本地备份和远程备份 mysqldump可以通过本地和远程服务器,对于SQL输出(CREATE and INSERT语句),本地或者远程可以备份并在客户端生成文件.对于带分隔符的文本文件,数据文件只能在服务器主机上生成. mysqlhotcopy只能在本地执行…

The Guide To Understanding mysqlreport This guide to understanding mysqlreport explains everything that mysqlreport can report. It also teaches how to interpret and understand all the values in context so that after reading a mysqlreport report ("a r…

https://www.percona.com/blog/2013/02/01/implications-of-metadata-locking-changes-in-mysql-5-5/ implications of Metadata Locking Changes in MySQL 5.5 Ovais Tariq  | February 1, 2013 |  Posted In: Insight for DBAs, Insight for Developers, MySQL While m…