Hacker News Reader

> What they're calling "synchronous multi-master" replication is actually implemented using "two-phase commit", which isn't replication per se, but rather application code using a database feature that allows specifically crafted database interactions to be written to multiple databases, and only successfully committing if the participating nodes agree that they've all committed.

I am not sure I understood, what is the difference between the two?

View on HN

As commonly defined, "replication" is something that happens in, and is managed by the database itself, or a daemon written for that purpose (whether the daemon works at the logical level, replicating database tuples, or at the physical level, replicating disk blocks), and of which an application can be largely, if not wholly agnostic. With two-phase commit, OTOH, an application has to be specifically written to take advantage of that functionality.

What happens if one of the nodes goes offline? System stops accepting requests or it keeps going and ends up in an inconsistent state?

Failure modes are defined by the two-phase commit protocol, the standard way of managing distributed database changes:

http://en.wikipedia.org/wiki/Two-phase_commit_protocol

Reply on news.ycombinator.com