Why does netstat show multiple entries for the Postgres process?
netstat -ap | grep postgre
tcp 0 0 localhost:5433 0.0.0.0:* LISTEN 15416/postgres tcp 0 0 localhost:5433 localhost:33138 ESTABLISHED 15435/postgres: 15/ unix 2 [ ACC ] STREAM LISTENING 75271 15416/postgres /var/run/postgresql/.s.PGSQL.5433
+----------------+ | pg_backend_pid | +----------------+ | 15435 | +----------------+
in another tab. run
ps aux | grep postgresreturn
postgres 15416 0.0 0.7 217652 29532 ? Ss 20:42 0:00 /usr/lib/postgresql/15/bin/postgres -D /var/lib/postgresql/15/main -c config_file=/etc/postgresql/15/main/postgresql.conf
First command return 3 rows. I get the meaning of the second row. So i guess 15416 refer to the server process id. But what does last row 75271 mean? I also didn't get the meaning of
unix 2in the last row.
I found the man page of netstat: https://man7.org/linux/man-pages/man8/netstat.8.html But I don't know how to display column.So the netsat result not that intuitive.
inna last edited by
Your server is listening on both a TCP socket, and a Unix domain socket (i.e. a special file, which has a name and directory like regular files do, but doesn't have any content and is just there to help client and server find each other).
That last line is about the Unix domain socket. 75271 is the inode of that file. Your grep has stripped off the header lines which netstat outputs, so of course you can't see them. It might be better to pipe the output to
grep. Or sent it to a file, then use your favorite text editor to look at the file.