如果我将一个进程分解为ruby，我是否需要重新连接到Mysql DB？

Question

I'm using the following environment.

• Rails 3.1
• Unicorn
• Mysql

I have to fork a process wich generate invoces. People told me to use

ActiveRecord::Base.connection.reconnect!

Because with some drivers could lost the connection with fork... I looked for some information about that but I'm more confused than before... here comes my doubts:

1 What's the difference between using

ActiveRecord::Base.connection.reconnect!

and

::ActiveRecord::Base.clear_all_connections!

before forking and

::ActiveRecord::Base.establish_connection

as shown here? Mysql, using fork in Ruby

2 Should I do it always?

If the answer is YES there is some place to put it as "fork configuration"?

3 what's happen with the connection when the forked process ends? should I close it? or does it close automatically? and what's append to the father's process connection?

4 Is it needed for all database connections?

I have read somewhere that is only for Postgres DB...

Thank you

Answer 1

不，从我的观点来看，你没有必要重新连接..你只需要连接，如果你想访问一个不同的数据库，据我所知rails为自己的mysql处理自己的重新连接。

Answer 2

You need to establish a new connection in your fork even it has no database access.

Because when then forked process exit, it will close the connection it copied, which is the same connection its parent process is using, this may interrupt the parent process. Vise versa.