PostgreSQL UNIX domain sockets vs TCP sockets

Question

I wonder if the UNIX domain socket connections with postgresql are faster then tcp connections from localhost in high concurrency rate and if it does, by how much?

Answer 1

Postgres core developer Bruce Momjian has blogged about this topic. Momjian states, "Unix-domain socket communication is measurably faster." He measured query network performance showing that the local domain socket was 33% faster than using the TCP/IP stack.