mysql - 如何在MySQL集群中使用选项Arbitration=WaitExternal？

Question

我目前正在阅读MySQL引用手册，并注意到NDB配置中有一个选项——Arbitrtaion=WaitExternal。问题是如何使用这个选项以及如何实现外部集群管理器？

The Arbitration parameter also makes it possible to configure arbitration in
such a way that the cluster waits until after the time determined by Arbitrat- 
ionTimeout has passed for an external cluster manager application to perform 
arbitration instead of handling arbitration internally. This can be done by 
setting Arbitration = WaitExternal in the [ndbd default] section of the config.ini
file. For best results with the WaitExternal setting, it is recommended that
ArbitrationTimeout be 2 times as long as the interval required by the external 
cluster manager to perform arbitration.

Answer 1

一些 git 注释和对原始设计文档的一些搜索表明以下内容:

当仲裁器要向仲裁器发送仲裁消息时，它将发出以下日志消息:

• 案例 ArbitCode::WinWaitExternal:{
• char buf[8*4*2+1];
• sd->mask.getText(buf);
• BaseString::snprintf(m_text, m_text_len,
• “等待外部仲裁后继续，”
• “节点:%s”，buf);
• 中断；
• }

所以例如等待外部仲裁后继续，节点:1,2

外部集群件应该检查​​此消息与 ArbitrationTimeout 的间隔相同。当外部集群件发现此消息时，应该杀死它决定丢失的数据节点仲裁。

NDB 数据节点将记录此终止，并将决定哪个节点生存的问题。