PostgreSQL自动增量是否可以实现竞争条件(Are race conditions possible with PostgreSQL auto-increment)

 mail()是一个黑盒子。 您告诉PHP尝试发送邮件，但主机已配置PHP以执行此操作。 
 
 它很可能只是在你的情况下调用sendmail。 该机器上的邮件队列也很可能不是世界上最快的。 共享主机通常超载。 
 
 您应该做的第一件事是询问您的主机邮件延迟。 也许出了点问题，他们可以修复它。 或者他们可能只是告诉你，一分半钟的等待时间不长。 
 
 还有很多其他选项，主要是以向您提供SMTP服务的公司的形式。 我不推荐一个，但我可以建议你跳到你最喜欢的搜索引擎，并寻找“smtp服务”。 我最近开始使用Amazon Simple Email Service 。 它应该是快速和良好的维护，它肯定是便宜的。 
 
 所有这些选项可能需要对您进行一些配置更改。 例如，您需要设置自定义DNS记录（对于DKIM和SPF ），以确保来自第三方提供商的邮件不会自动标记为垃圾邮件。 
 
 使用SMTP与PHP很容易。 那里有很多邮件生成选项。 我个人最喜欢的是SwiftMailer 。 它甚至还有Amazon SES的传输选项 。 
 
 当然，最后一个选项是获取您自己的虚拟专用服务器或专用服务器，这将允许您根据需要配置外发邮件，但代价是需要知道如何维护该服务器。 
 
 
 编辑： 相关编码恐怖帖的强制性链接 。 

mail() is a black box. You're telling PHP to try sending a mail however the host has configured PHP to do so.
 
It's very likely that it's just calling sendmail in your case. It's also very likely that the mail queue on that machine isn't the fastest in the world. Shared hosting machines are often overloaded.
 
The very first thing you should do is ask your host about the mail delay. Perhaps something is wrong, and they can fix it. Or they might just tell you that a minute and a half is not a long time to wait.
 
There are lots of other options, mostly in the form of companies that provide an SMTP service to you. I can't recommend one, but I can recommend that you pop over to your favorite search engine and look for "smtp service." I've recently starting working with Amazon Simple Email Service. It's supposed to be fast and well-maintained, and it's certainly inexpensive.
 
All of those options are likely going to require some configuration changes on your end. For example, you'll want to set up custom DNS records (for DKIM and SPF) to ensure that mail from a third party provider isn't automatically flagged as spam. 
 
Using SMTP with PHP is dead easy. There are plenty of mail generating options out there. My personal favorite is SwiftMailer. It even has a transport option for Amazon SES.
 
The final option, of course, is grabbing your own virtual private server or dedicated server, which will let you configure outgoing mail as you desire, at the cost of needing to know how to maintain that server.
 
 
Edit: Obligatory link to relevant Coding Horror post.