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From Mike Carey <dtab...@gmail.com>
Subject Re: Status of the Metadata fixes (https://asterix-gerrit.ics.uci.edu/#/c/323/)
Date Wed, 05 Aug 2015 05:35:22 GMT
Oh - I missed the point on this - WIERD!  This seems like a "bug" - 
i.e., I don't think ? should be part of the syntax either, i.e., I agree 
with Ildar that this makes no sense - I'm not sure why it's there.  
Let's get rid of that and then we won't need this bit of metadata 
either.  (Though we'll need the code changes to fix this.)

On 8/4/15 2:34 PM, Ildar Absalyamov wrote:
> As Till mentioned in the comment the problem is that we might need
> nullability information in two cases:
> 1) When a field is declared nullable in the schema. In this case the
> information is persisted into the "IsNullable" metadata field, introduced
> in the patch
> 2) When we are declaring an open index of a nullable type (which is a
> useless thing to do in my opinion). In this case right now we persist only
> the type name, thus a "?" marker is needed to deserialize the proper type
> back.
> The conclusion was to store nullability information in "IsNullable" field
> in the second case as well, which as I hoped will allow to reuse some code
> from schema serialization. However the format of the metadata record is
> slightly different in the case of an index. I did not invest that much time
> into the issue since the last week, was hoping to finish soon.
>
> My main concern is whether the second case is valid at all. When an open
> index is declared on the field it does not matter if the type of the index
> is nullable or not, since the field value could potentially be null by
> definition.
> However, as Till mentioned in our discussion, it might make a difference if
> we distinguish between the case when field "foo" has a value "null" and the
> case when "foo" is completely missing from the record. Thoughts?
>
> 2015-08-04 14:07 GMT-07:00 Till Westmann <tillw@apache.org>:
>
>> I’ve added a comment to the review about what I think is an open issue.
>> It would be nice to get more eyes/opinions on this to see if this is an
>> issue and should be addressed.
>>
>> Thanks,
>> Till
>>
>>> On Aug 4, 2015, at 1:53 PM, Steven Jacobs <sjaco002@ucr.edu> wrote:
>>>
>>> It still has my +1 (I reviewed the changes since patchset 3), but it's
>>> waiting for a +2 from Till.
>>> Steven
>>>
>>> On Tue, Aug 4, 2015 at 1:36 PM, Ian Maxon <imaxon@uci.edu> wrote:
>>>
>>>> Hi,
>>>> This change is the last feature on the checklist before release,
>>>> AFAIK. Just wanted to start a thread so there's visibility into the
>>>> status of it, as I think there's been things going on behind the
>>>> scenes. I believe right now it is under review, and that Till has
>>>> provided comments to Ildar. However I'm not sure what has been going
>>>> on after that. Will this patch need another round of fixes and review,
>>>> or are the comments  something that is addressable post-release
>>>> without a breaking metadata change? If it does need more work, what is
>>>> the time frame for that?
>>>>
>>>> -Ian
>>
>


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