@ConstantFunction(name = "utc_timestamp", argTypes = {}, returnType = DATETIME)
    public static ConstantOperator utcTimestamp() {
        // for consistency with mysql, ignore milliseconds
        LocalDateTime utcStartTime = Instant.ofEpochMilli(ConnectContext.get().getStartTime() / 1000 * 1000)
                .atZone(ZoneOffset.UTC).toLocalDateTime();
        return ConstantOperator.createDatetimeOrNull(utcStartTime);
    }
@Test
    public void testUTCTimestamp() {
        ConnectContext ctx = new ConnectContext(null);
        ctx.setThreadLocalInfo();
        ctx.setStartTime();
        LocalDateTime expected = Instant.ofEpochMilli(ctx.getStartTime() / 1000 * 1000)
                .atZone(ZoneOffset.UTC).toLocalDateTime();
        assertEquals(expected, ScalarOperatorFunctions.utcTimestamp().getDatetime());
    }