Does postgres process requests at the same time?

Question

PostgreSQL

I don't fully understand if Postgres can process, for example, 2 requests at the same time? That is, if we take 2 connections from the pool and access the database at the same time, will they be processed at the same time? And if, say, one of the connections will execute the request for a very long time (say, 10 seconds), then the second connection with a simple request can be executed in parallel? And, if so, how many requests can be executed in parallel? What does it depend on?

Answer 1

From transactionality and the presence of a cluster. Transactions are always executed sequentially, and any other requests - in parallel. A distributed cluster has its own characteristics