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HBase >> mail # dev >> Re: HBase Types: Explicit Null Support


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Re: HBase Types: Explicit Null Support
Maybe if we can keep nullability separate from the
serialization/deserialization, we can come up with a solution that
works? We're able to essentially infer that a column is null based on
its value being missing or empty. So if an iterator through the row key
bytes could detect/indicate that, then an application could "infer" the
value is null.

We're definitely planning on keeping byte[] accessors for use cases that
need it. I'm curious on the geographic data case, though, could you use
a fixed length long with a couple of new SQL built-ins to encode/decode
the latitude/longitude?

On 04/01/2013 11:29 PM, Jesse Yates wrote:
> Actually, that isn't all that far-fetched of a format Matt - pretty common
> anytime anyone wants to do sortable lat/long (*cough* three letter agencies
> cough*).
>
> Wouldn't we get the same by providing a simple set of libraries (ala
> orderly + other HBase useful things) and then still give access to the
> underlying byte array? Perhaps a nullable key type in that lib makes sense
> if lots of people need it and it would be nice to have standard libraries
> so tools could interop much more easily.
> -------------------
> Jesse Yates
> @jesse_yates
> jyates.github.com
>
>
> On Mon, Apr 1, 2013 at 11:17 PM, Matt Corgan <[EMAIL PROTECTED]> wrote:
>
>> Ah, I didn't even realize sql allowed null key parts.  Maybe a goal of the
>> interfaces should be to provide first-class support for custom user types
>> in addition to the standard ones included.  Part of the power of hbase's
>> plain byte[] keys is that users can concoct the perfect key for their data
>> type.  For example, I have a lot of geographic data where I interleave
>> latitude/longitude bits into a sortable 64 bit value that would probably
>> never be included in a standard library.
>>
>>
>> On Mon, Apr 1, 2013 at 8:38 PM, Enis Söztutar <[EMAIL PROTECTED]> wrote:
>>
>>> I think having Int32, and NullableInt32 would support minimum overhead,
>> as
>>> well as allowing SQL semantics.
>>>
>>>
>>> On Mon, Apr 1, 2013 at 7:26 PM, Nick Dimiduk <[EMAIL PROTECTED]> wrote:
>>>
>>>> Furthermore, is is more important to support null values than squeeze
>> all
>>>> representations into minimum size (4-bytes for int32, &c.)?
>>>> On Apr 1, 2013 4:41 PM, "Nick Dimiduk" <[EMAIL PROTECTED]> wrote:
>>>>
>>>>> On Mon, Apr 1, 2013 at 4:31 PM, James Taylor <[EMAIL PROTECTED]
>>>>> wrote:
>>>>>
>>>>>>  From the SQL perspective, handling null is important.
>>>>>
>>>>>  From your perspective, it is critical to support NULLs, even at the
>>>>> expense of fixed-width encodings at all or supporting representation
>>> of a
>>>>> full range of values. That is, you'd rather be able to represent NULL
>>>> than
>>>>> -2^31?
>>>>>
>>>>> On 04/01/2013 01:32 PM, Nick Dimiduk wrote:
>>>>>>> Thanks for the thoughtful response (and code!).
>>>>>>>
>>>>>>> I'm thinking I will press forward with a base implementation that
>>> does
>>>>>>> not
>>>>>>> support nulls. The idea is to provide an extensible set of
>>> interfaces,
>>>>>>> so I
>>>>>>> think this will not box us into a corner later. That is, a
>> mirroring
>>>>>>> package could be implemented that supports null values and accepts
>>>>>>> the relevant trade-offs.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Nick
>>>>>>>
>>>>>>> On Mon, Apr 1, 2013 at 12:26 PM, Matt Corgan <[EMAIL PROTECTED]>
>>>>>>> wrote:
>>>>>>>
>>>>>>>   I spent some time this weekend extracting bits of our
>> serialization
>>>>>>>> code to
>>>>>>>> a public github repo at http://github.com/hotpads/**data-tools<
>>>> http://github.com/hotpads/data-tools>
>>>>>>>> .
>>>>>>>>    Contributions are welcome - i'm sure we all have this stuff
>> laying
>>>>>>>> around.
>>>>>>>>
>>>>>>>> You can see I've bumped into the NULL problem in a few places:
>>>>>>>> *
>>>>>>>>
>>>>>>>> https://github.com/hotpads/**data-tools/blob/master/src/**
>>>>>>>> main/java/com/hotpads/data/**primitive/lists/LongArrayList.**java<
>> https://github.com/hotpads/data-tools/blob/master/src/main/java/com/hotpads/data/primitive/lists/LongArrayList.java