• Why not it in warn_if_dir_in_part_elem() ?
• Why the check for DB_TYPE_INNODB ?
  • The warning "`Warning 1618 <DATA DIRECTORY> option ignored` is issued for any engine
  • No engine-specific checks in the general server code, please

I understand that engine-specific code in sql is not a good idea. But for this particular topic some InnoDB-specific code already exists: https://github.com/MariaDB/server/blob/ada54101a7185782657813c553907f61f2a35faf/sql/ha_partition.cc#L2201

I've tried first to put my code here, but eventually put it in another place because bool add_or_reorg_part is very handy for my check and I've reused it.

Right now I can't move that check inside InnoDB because it should work with ALGORITHM=COPY too. Or maybe I don't understand something?

warn_if_dir_in_part_elem is a different think. Warning should mention InnoDB, because it warns on InnoDB-specific case.

I've updated PR: added separate WARN_

It feels like i don't understand something. But as far as i can see
it is not an engine-specific problem. MariaDB ignores DATA DIRECTORY option for all the engines

MariaDB [test]> CREATE TABLE t (a INT NOT NULL) ENGINE=myisam DATA DIRECTORY = 'maria100/data/partitions_here/';

Query OK, 0 rows affected (0.09 sec)

MariaDB [test]> alter table t data directory = 'maria100/data/partitions_somewhere_else/';

Query OK, 0 rows affected, 1 warning (1 min 31.04 sec)

Records: 0  Duplicates: 0  Warnings: 1

MariaDB [test]> show warnings;

+---------+------+---------------------------------+

| Level   | Code | Message                         |

+---------+------+---------------------------------+

| Warning | 1618 | <DATA DIRECTORY> option ignored |

+---------+------+---------------------------------+

1 row in set (0.00 sec)

And that warning is raised in Sql_cmd_alter_table::execute().
I'd say we should raise same warning for the ALTER REORGANIZE PARTITION
somewhere there too.

> it is not an engine-specific problem. MariaDB ignores DATA DIRECTORY option for all the engines

DATA DIRECTORY for whole table and for partitions are different things.

Somewhat similar check for partitions happens here https://github.com/MariaDB/server/blob/90b66c169957962de612bc951cdf369cdfccc99c/sql/partition_info.cc#L1606

If you think it would be better I can merge my function with that one.

> > it is not an engine-specific problem. MariaDB ignores DATA DIRECTORY option for all the engines
> DATA DIRECTORY for whole table and for partitions are different things.

Do you mean DATA DIRECTORY for the partition tables is engine-specific? I need to see a test case showing that.

BTW the warn_if_dir_or_idx_in_innodb_part_elem() doesn't warn on that query:

MariaDB [test]> ALTER TABLE t REORGANIZE PARTITION p1,p2 INTO (

PARTITION p1 DATA DIRECTORY = '/home/hf/maria103/data/partitions_somewhere_else/', 

PARTITION p2 DATA DIRECTORY = '/home/hf/maria103/data/partitions_somewhere_else/');

even if the 't' partitions are InnoDB.

Also I'd note that the warn_if_dir_or_idx_in_innodb_part_elem() only works
when called from prep_alter_part_table() checking the add_or_reorg_part flag.
It seems nicer to just do it in the prep_alter_table() then.

> Somewhat similar check for partitions happens here
So the warn_if_dir_in_part_elem() checks the MODE_NO_DIR_IN_CREATE flag.
In fact that flag is checked in many places of the code which i don't like.
And i'd prefer the ignored-data-directory check in a single place - Sql_cmd_alter_table::execute looks good enough to me.

I've updated PR.

> Do you mean DATA DIRECTORY for the partition tables is engine-specific? I need to see a test case showing that.

It's main.partition_not_windows

Check was moved to prep_alter_part_table(). Table should be opened to perform this check. Sql_cmd_alter_table::execute() is too early, f.ex.

> And i'd prefer the ignored-data-directory check in a single place - Sql_cmd_alter_table::execute looks good enough to me.

It's already in one place and works for both ALTER TABLE and CREATE TABLE. If I'll move that check to Sql_cmd_alter_table::execute() I will also have to duplicate it somewhere for CREATE TABLE.

https://github.com/MariaDB/server/commit/031c695b8c865e5eb6c4c09ced404ae08f98430f