Add prefer_simple_protocol option to ParseConfig

refs #650

conn.go

@@ -160,11 +160,22 @@ func ParseConfig(connString string) (*ConnConfig, error) {
 		}
 	}
 
+	preferSimpleProtocol := false
+	if s, ok := config.RuntimeParams["prefer_simple_protocol"]; ok {
+		delete(config.RuntimeParams, "prefer_simple_protocol")
+		if b, err := strconv.ParseBool(s); err == nil {
+			preferSimpleProtocol = b
+		} else {
+			return nil, errors.Errorf("invalid prefer_simple_protocol: %v", err)
+		}
+	}
+
 	connConfig := &ConnConfig{
 		Config:               *config,
 		createdByParseConfig: true,
 		LogLevel:             LogLevelInfo,
 		BuildStatementCache:  buildStatementCache,
+		PreferSimpleProtocol: preferSimpleProtocol,
 		connString:           connString,
 	}
 

conn_test.go

@@ -169,6 +169,26 @@ func TestParseConfigExtractsStatementCacheOptions(t *testing.T) {
 	require.Equal(t, stmtcache.ModeDescribe, c.Mode())
 }
 
+func TestParseConfigExtractsPreferSimpleProtocol(t *testing.T) {
+	t.Parallel()
+
+	for _, tt := range []struct {
+		connString           string
+		preferSimpleProtocol bool
+	}{
+		{"", false},
+		{"prefer_simple_protocol=false", false},
+		{"prefer_simple_protocol=0", false},
+		{"prefer_simple_protocol=true", true},
+		{"prefer_simple_protocol=1", true},
+	} {
+		config, err := pgx.ParseConfig(tt.connString)
+		require.NoError(t, err)
+		require.Equalf(t, tt.preferSimpleProtocol, config.PreferSimpleProtocol, "connString: `%s`", tt.connString)
+		require.Empty(t, config.RuntimeParams["prefer_simple_protocol"])
+	}
+}
+
 func TestExec(t *testing.T) {
 	t.Parallel()