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Re: [GSoC] MDEV-371- index on BLOB


Hi Sergei,

I am working on writing proposal for this project currently.

Currently MariaDB lets user create index upto 1000 bytes. should we use new
approach for prefixes less than <1000 chars also(but >63 or some other
threshold) to improve performance?

Should I first work on MyISAM or Aria storage engine? I am thinking of
starting with one and then porting to other.

Smit Hinsu

On Mon, Mar 17, 2014 at 8:33 PM, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:

> Hi, Smit!
> On Mar 17, smit hinsu wrote:
> > Hi Sergei and Roberto,
> >
> > My name is Smit Hinsu and I am final year undergrad student. I have good
> > knowledge about database internals and good experience with C++.
> >
> > I find feature of creating index on BLOB quickly using MD-5 interesting.
> I
> > have understood basic requirements for this feature. I have following
> > questions in my mind currently.
> >
> > I think, HASH index is not supported in MySQL's version of MyISAM storage
> > engine. Has MariaDB removed this restriction?
> No, it is not supported in MariaDB either. I mean, neither in MySQL nor
> in MariaDB you can write
> This doesn't work.
> But both in MySQL and in MariaDB, MyISAM actually supports these
> indexes! They are not available to the SQL user, but they are there in
> the code. This task, precisely, is to provide SQL access to this
> feature.
> > We should support index for BLOB for BTREE index also in which we store
> > only hash value of the value in BTREE. Is this possible?
> That's what MyISAM does, yes.
> > Can you suggest me some startup task related to index or storage engine
> > which can make me familiar with the related parts? I have started to look
> > at code.
> Look in storage/myisam for "MI_UNIQUEDEF" - see where this structure is
> used and how.
> Regards,
> Sergei