MySQL-官方文档摘抄

点击(此处)折叠或打开

成都创新互联自2013年创立以来,先为平陆等服务建站,平陆等地企业,进行企业商务咨询服务。为平陆企业网站制作PC+手机+微官网三网同步一站式服务解决您的所有建站问题。

  1. There are three phases to an index build.
  2. In the first phase, the clustered index is scanned, and index entries are generated and added to the sort buffer. When the sort buffer becomes full, entries are sortedand writtenout to a temporary intermediate file. This process is also known as a “run”.
  3. In the second phase, with oneor more runs written to the temporary intermediate file, a merge sort is performed on all entriesin the file.
  4. In the thirdand final phase, the sorted entries are insertedinto the B-tree.


点击(此处)折叠或打开

  1. When running an online DDL operation, the thread that runs the ALTER TABLE statement applies an “online log” of DML operations that were run concurrently on the same table from other connection threads. When the DML operations are applied, it is possible to encounter a duplicate key entry error(ERROR 1062(23000): Duplicate entry), evenif the duplicate entry is only temporaryand would be reverted by a later entryin the “online log”.This is similar to the ideaof a foreign key constraint checkin InnoDBin which constraints must hold during a transaction.



点击(此处)折叠或打开

  1. Semisynchronous Replication

  2. The slave acknowledges receipt of a transaction's events only after the events have been written to its relay log and flushed to disk. 

半同步只负责relaylog的落盘, 并不关心Slave是否真的有应用这些events, 所以Master的双1+半同步正常可以确认binlog到了Slave端, Slave在不出问题的情况下能做到最终一致性;



点击(此处)折叠或打开

  1. innodb_lock_wait_timeout applies to InnoDB row locks only. A MySQL table lock does not happen inside InnoDB and this timeout does not apply to waits for table locks.
  2. The lock wait timeout value does not apply to deadlocks when innodb_deadlock_detect is enabled (the default) because InnoDB detects deadlocks immediately and rolls back one of the deadlocked transactions. When innodb_deadlock_detect is disabled, InnoDB relies 

    on innodb_lock_wait_timeout for transaction rollback when a deadlock occurs. 

For example, metadata lock


分享文章:MySQL-官方文档摘抄
浏览路径:http://bzwzjz.com/article/jdijsh.html

其他资讯

Copyright © 2007-2020 广东宝晨空调科技有限公司 All Rights Reserved 粤ICP备2022107769号
友情链接: 成都网站建设公司 网站设计制作报价 成都商城网站制作 成都网站建设 网站建设推广 重庆网站建设 做网站设计 网站制作公司 成都网站制作 成都营销网站制作 重庆网站建设 宜宾网站设计 成都定制网站建设 移动网站建设 移动手机网站制作 成都网站建设 高端网站设计 成都网站建设 成都网站建设 营销网站建设 成都网站建设流程 成都网站建设