如何确保2个远程操作成功完成，如果其中一个远程操作失败，则回滚所有操作？

Question

I plan to use PHP to connect to 2 remote servers. One is a MySQL database. The other one is a Job Queue server.

For every Job that I push to the Job Queue server, I want to ensure that (exactly) 1 record is inserted into the MySQL DB. I want to ensure that the MySQL DB records and the Job Queue tasks execution are 100% in sync.

Since both are remote servers, I am worried that sometimes there may be connection problem to one of the servers (or both).

In my PHP application, how can I ensure that 2 remote operations complete successfully, and rollback all operations if 1 of the remote operations fails? Is there any programming best practices that I should follow for this kind of scenario?

Answer 1

This sounds like a pretty basic AND use case. Since you're in PHP, you're not worried about asyncronous calls or timeout waits. To pseudocode it:

Start Transaction1
    ... do stuff... //transaction 1 still open, no commit
Start Transaction2
    ... do more stuff...
If (Transaction1 success && Transaction2 success) {
    commit Transaction1
    commit Transaction2
} else {
    rollback Transaction1
    rollback Transaction2
}