postgresql, streaming replication is synchronous?

Question

I've setup streaming replication and wonder if it's synchrounous.. if it's blocking.

Which implys when slave goes down, the synchronous rep will be blocked and there will be problems service client requests.

Or do I need not to worry about such a scenario?

Answer 1

Yes, with synchronous replication a COMMIT will block until the required standby servers have reported that they have received the information.

That leads to reduced availability if you only have a single standby server. This is not a PostgreSQL shortcoming, but a fundamental necessity; read about the CAP theorem for more.

The way to deal with that is to have more than one standby server, so that life can go on if a standby server fails.