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From abdullah alamoudi <bamou...@gmail.com>
Subject Re: Question about open indexes
Date Tue, 22 Sep 2015 07:18:37 GMT
I see.
Thanks Ildar,

Abdullah.

Amoudi, Abdullah.

On Tue, Sep 22, 2015 at 10:04 AM, Ildar Absalyamov <
ildar.absalyamov@gmail.com> wrote:

> Abdullah,
>
> If I remember correctly whenever a secondary open index is created all
> existing records would be casted to a proper type to ensure that the index
> creation is valid.
> As for the overall correctness of casting operation, semantically creating
> an open index is the same thing as altering the dataset type. The current
> implementation allows only one open index of particular type created on a
> single field. If we would have had “alter datatype” functionality the open
> indexing would not be required at all.
>
> > On Sep 21, 2015, at 23:25, abdullah alamoudi <amoudi@apache.org> wrote:
> >
> > More thoughts:
> > I assume the intention of the cast was just to make sure if the open
> field
> > exists, it is of the specified type. Moreover, the un-casted record
> should
> > be inserted into the index.
> > If my assumptions are not correct, please, let me know ASAP.
> >
> > I have two thoughts on this:
> > 1. Actually, insert plans show that the records being inserted into the
> > primary index is actually the casted record creating the issue described
> > above.
> >
> > 2. I don't believe this is the right way to ensure that the open field if
> > exists is of the right type. why not extract the field using field access
> > by name function and then verify the type using the field tag?
> >
> >
> >
> > On Tue, Sep 22, 2015 at 9:11 AM, abdullah alamoudi <amoudi@apache.org>
> > wrote:
> >
> >> Hi Dev, @Ildar,
> >>
> >> In the insert pipeline for datasets with open indexes, we introduce a
> cast
> >> function before the insert and so one would expect the records to look
> like
> >> the casted record type which I assume has {{the closed fields + a
> nullable
> >> field}}.
> >>
> >> The question is, what happens to the previously existing records?, since
> >> now the index has both, records of the original type and records of the
> >> casted type.
> >>
> >> Thanks,
> >> Abdullah.
> >>
>
> Best regards,
> Ildar
>
>

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