Add Go/PostgreSQL version

Results

@@ -33,3 +33,9 @@ rorschach:~database_connect_bench 0:14 :-) 1099% time ./dcb_perl_psql
 0.00254458002746105 session 2
 ./dcb_perl_psql  0.05s user 0.01s system 93% cpu 0.068 total
 
+trintignant:~/wrk/database_connect_bench 19:29 :-) 1077% time ./dcb_go_psql
+2021-05-07 19:32:40.307679 +0200 CEST
+0.017314667 connect
+0.0178164 session
+./dcb_go_psql  0.01s user 0.01s system 52% cpu 0.044 total
+

dcb_go_psql.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"time"
+	"fmt"
+	"log"
+	"database/sql"
+
+	_ "github.com/lib/pq"
+)
+
+func main() {
+	t0 := time.Now()
+	db, err := sql.Open("postgres", "host=/run/postgresql")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	tx, _ := db.Begin()
+	d1 := time.Since(t0)
+	row := tx.QueryRow("select current_timestamp")
+	var db_ts time.Time
+	row.Scan(&db_ts)
+	fmt.Println(db_ts)
+	db.Close()
+	d2 := time.Since(t0)
+	fmt.Println(d1.Seconds(), "connect")
+	fmt.Println(d2.Seconds(), "session")
+}