Hello Sergi

Actually I was prototyping for blob and varchar   for aria and myisam storage engine.

My prototype worked for complex definations like

craete table(abc int primary key, blob_col blob unique, varchar_col varchar(1000) unique) engine=myisam;

Solved the issue of frm file incosistance.

As you suggested for doing it for innodb i am current working on it.Innodb does not natively support hash based index.

when we run select distinct column from tbl;

it use create_internal_tmp_table() which uses maria storage engine for creating tmp table.

But query like this works

MariaDB [sachin]> create table iu2(abc blob unique);

Query OK, 0 rows affected (0.04 sec)

MariaDB [sachin]> insert into iu2 values(1);

Query OK, 1 row affected (0.03 sec)

MariaDB [sachin]> insert into iu2 values(1);

ERROR 1062 (23000): Duplicate entry '1' for key 'abc'

this query does not use hash but it simply compares values

Will write a proposal shortly.

Regards

sachin

On Sat, Mar 19, 2016 at 1:52 AM, Sergei Golubchik <serg@mariadb.org> wrote:

Hi, Sachin!

On Mar 18, Sachin Setia wrote:
>
> ERROR 1030 (HY000): Got error 190 "Incompatible key or row definition
> between the MariaDB .frm file and the information in the storage engine.
> You have to dump an" from storage engine MyISAM
>
> We are getting this becuase in mi_create for each unique_def it creates one
> keydef and writes it.And this creates two  problem
> 1. frm keydef algorithm is different from saved kefdef algorithm(always
> zero) for the time I have solved this problem .
>
> 2.Mismatch between keydef's keysegs the reason for this is when mi_create
> creates keyseg for unique_def it did not keeps the orignal uniquedef's
> keyseg parameters in mind like language start length which creates problem
> in check_definition function in ha_myisam.cc.I am currently working on it
> Once again sorry for this foolish mistake.
> Regars
> sachin

No problem, everyone makes mistakes :)

It's a prototype, after all. It's much more important that you
understand how the code works and why it doesn't work.

Regards,
Sergei
Chief Architect MariaDB
and security@mariadb.org