ROUND malfunction...!?!

Arturs_Strauss

Hi,

 

Please correct me or explain me how this works or otherwise it seems quite like a really bad bug.

Here is an example of query where I am summing two numbers and rounding the number two digits after the decimal point:

 

select round(sum(x.some_number),2.0) round_sum,
           round((0.2440 + 0.0010),2.0) other_number,
          (0.2440 + 0.0010) just_number,
          round(0.2450,2.0) other_round_number
 from (select 0.2440 as some_number
            union all
            select 0.0010 as some_number) x;

the result for all of these calculations are:

round_sum  other_number just_number  other_round_number

0.24                      0.24                      0.2450                          0.24

 

All of these results are incorrect except “just_number”.

I have double checked with calculator, excel or whatever other tool which is smart enough to round numbers. And all of these give out result: 0.25!!! Which is correct.

How can you explain that?

 

And it is on v7.1

id10t

Hi!

For me looks like a bug. My explanation why its look like a bug:

daniel=> select round(1.005, 2.0), round(1.105, 2.0), round(1.205, 2.0), round(1.305, 2.0);
 round | round | round | round 
-------+-------+-------+-------
     1 |   1.1 |  1.21 |   1.3
(1 row)

Lets check its not a problem of inexact values of floats and implicitly will convert all values to money data type [witch is NUMERIC(18,4)]

daniel=> select round(1.005::money, 2.0), round(1.105::money, 2.0), round(1.205::money, 2.0), round(1.305::money, 2.0);
 round | round | round | round 
-------+-------+-------+-------
     1 |   1.1 |  1.21 |   1.3
(1 row)

Regards.

Arturs_Strauss

Hi mr. „id10t”!

Thanks for your replay and for that you confirmed my assumption that this is a bug.
And it is quite bad bug – basically it means if I have some kind of calculations and out coming number has more than one digit after decimal point, which is important to me, they are all wrong if I use ROUND function.

Perhaps you know – is there a way to report the bug to HP Vertica? Or this post is the only way to drag the attention of support team and hope that they will fix it?

id10t

Hi!

Any way I will post an answer

Sorry Im not an EE customer, I can't open a ticket, I just tried to investigate from my point of view. Also Im not a Vertica employee so I can't declare that is a bug, only Vertica engineers/employees can do it.

Perhaps you know – is there a way to report the bug to HP Vertica?

Only EE customers can open a ticket and there are 2 ways - saleforce.com and mail. From obvious reasons I can't post rules for mail reports, but if you are enterprise customer you can contact with your sales agent.

I'm sorry, that was useless.
Regards.