[tarantool-patches] Re: [PATCH 3/3] sql: fix passing FP values to integer iterator

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

On 28/05/2019 10:19, Konstantin Osipov wrote:
> * Vladislav Shpilevoy <v.shpilevoy@tarantool.org> [19/05/28 09:22]:
>> On 25/05/2019 08:51, Konstantin Osipov wrote:
>>> * Nikita Pettik <korablev@tarantool.org> [19/05/24 20:42]:
>>>> That happened due to the fact that type casting mechanism (OP_ApplyType)
>>>> doesn't affect FP value when it is converted to integer. Hence, FP value
>>>> was passed to the iterator over integer field which resulted in error.
>>>> Meanwhile, comparison of integer and FP values is legal in SQL.  To cope
>>>> with this problem for each equality comparison involving integer field
>>>> we emit OP_MustBeInt, which checks whether value to be compared is
>>>> integer or not. If the latter, we assume that result of comparison is
>>>> always false and continue processing query. 
>>>
>>> Are you sure other vendords would fail to return any results for
>>> WHERE foo = 1.0?
>>
>> I do not understand, what you are talking about. It works.
> 
> Is this with the patch applied? 

I do not know, and it does not matter, IMO. With the patch
it works.

> 
>>
>> tarantool> box.execute("CREATE TABLE t1(id INT PRIMARY KEY, a INT UNIQUE);")
>> tarantool> box.execute("INSERT INTO t1 VALUES (1, 1);")
>> tarantool> box.execute("SELECT a FROM t1 WHERE a = 1.0;")
> 
> I don't understand how it works then.
> a = 1.0 works but a = 1.1 doesn't?

Yes, it is a school math. 1 != 1.1, but 1 == 1.0