jackc/pgx · error

server is in standby mode

Error message

server is in standby mode

What it means

Target-session-attrs validation error: 'select pg_is_in_recovery()' returned true, meaning the server is in recovery (a standby), but target_session_attrs=primary requires a non-recovering primary. pgx discards this connection and tries the next host in the list.

Solutions

1. Connect to the primary node
2. Remove target_session_attrs=primary if standbys are acceptable
3. With multiple hosts, ensure the primary's address is included so some candidate can satisfy the requirement

When it happens

Trigger: Thrown at pgconn/config.go:1089 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /api/errors/719913cdf29bbc73. Report an issue: GitHub.

Appendix: source

Thrown at pgconn/config.go:1089

	}

	if string(result[0].Rows[0][0]) != "t" {
		return errors.New("server is not in hot standby mode")
	}

	return nil
}

// ValidateConnectTargetSessionAttrsPrimary is a ValidateConnectFunc that implements libpq compatible
// target_session_attrs=primary.
func ValidateConnectTargetSessionAttrsPrimary(ctx context.Context, pgConn *PgConn) error {
	result, err := pgConn.Exec(ctx, "select pg_is_in_recovery()").ReadAll()
	if err != nil {
		return err
	}

	if string(result[0].Rows[0][0]) == "t" {
		return errors.New("server is in standby mode")
	}

	return nil
}

// ValidateConnectTargetSessionAttrsPreferStandby is a ValidateConnectFunc that implements libpq compatible
// target_session_attrs=prefer-standby.
func ValidateConnectTargetSessionAttrsPreferStandby(ctx context.Context, pgConn *PgConn) error {
	result, err := pgConn.Exec(ctx, "select pg_is_in_recovery()").ReadAll()
	if err != nil {
		return err
	}

	if string(result[0].Rows[0][0]) != "t" {
		return &NotPreferredError{err: errors.New("server is not in hot standby mode")}
	}

	return nil

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