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Re: GSoC 2016:Unique indexes for blobs


Hello Jan,

         Thanks for the kind response and for giving the details of
implementation. I am going to explore InnoDB data dictionary before the
official coding period starts.


On 24 March 2016 at 01:47, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:

> Hi, Jan!
> On Mar 23, Jan Lindström wrote:
> > Hi,
> >
> > All below is correct and naturally you may re-implement duplicate search
> on
> > different index type. I think there is more code that needs change as
> this
> > new index type would contain a column (hash value of the blob field) that
> > is not on stored on base table, right ? Indexed columns are also stored
> > inside a InnoDB data dictionary persistently, so that part would also
> need
> > change (dict/dict0*.cc files). Actually, you could store blob has also to
> > table, it could make things easier. Secondly, remember that unique keys
> can
> > be used inside a InnoDB as foreign keys, this is again a design question,
> > do you allow blobs to be foreign keys or not. Finally, unique key with
> > NULL can be used as primary key i.e. clustered key on InnoDB, using blobs
> > hash on that might be out of reach on this timetable.
> >
> > R: Jan Lindström
> > Principal Engineer
> > InnoDB
> Agree, blobs (even UNIQUE NOT NULL) cannot be used as primary keys.
> For simplicity I would not support foreign keys either, this can be
> added later.
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx

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