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From Ildar Absalyamov <ildar.absalya...@gmail.com>
Subject Re: Status of the Metadata fixes (https://asterix-gerrit.ics.uci.edu/#/c/323/)
Date Wed, 05 Aug 2015 06:25:35 GMT
OK, so I will include an index-creation time check to avoid the nullable types in this case
then.

> On Aug 4, 2015, at 22:35, Mike Carey <dtabass@gmail.com> wrote:
> 
> 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
>>> 
>> 
> 

Best regards,
Ildar


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