如何在MySQL Cluster中使用选项Arbitrtaion = WaitExternal？

Question

我正在阅读MySQL参考手册并注意到有一个NDB配置选项 - Arbitrtaion = WaitExternal。问题是如何使用此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注释和一些原始设计文档的搜索说明如下：

当仲裁员即将向仲裁员发送仲裁消息时，它将发出以下日志消息：

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

所以，例如 等待外部仲裁后继续，节点：1,2

外部集群件应检查此消息 与ArbitrationTimeout处于相同的间隔。 当它发现此消息时，外部群集 应该杀死它决定丢失的数据节点 仲裁。

NDB数据节点会注意到这个kill 决定哪个节点要生存。