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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 07:15:09 GMT
Oh yeah, could be. I will check that.

> On Aug 5, 2015, at 00:03, Mike Carey <dtabass@gmail.com> wrote:
> 
> Won't fixing the grammar to eliminate ? make that unnecessary?
> 
> 
> On 8/5/15 12:00 AM, Ildar Absalyamov wrote:
>> Since we are talking about open index case, we do already have a check that the indexed
field(s) is\are not a part of the schema.
>> Additional check will restrict the user-provided type of the field(s) to non-nullable
build-in type only.
>> 
>>> On Aug 4, 2015, at 23:46, Mike Carey <dtabass@gmail.com> wrote:
>>> 
>>> Hmmm - I think I understand...  I think we need to remove the ? from the create
index syntax (it isn't something it makes any sense to allow users to say) and then we should
make sure at create time that the indexed field or fields are NOT a part of the known schema
of the target dataset.  Right?
>>> 
>>> On 8/4/15 11:25 PM, Ildar Absalyamov wrote:
>>>> 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
>>>> 
>> Best regards,
>> Ildar
>> 
> 

Best regards,
Ildar


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