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Minor
Description
If I create a new index and specify a type which is not supported by the storage engine:
- the index is created using the default type;
- I get no error / warning.
For example, I tried to create a hash index for XtraDB:
MariaDB [test]> CREATE TABLE t5 (c1 INT) ENGINE = XtraDB; Query OK, 0 rows affected, 2 warnings (0.08 sec) MariaDB [test]> ALTER TABLE t5 ADD INDEX i1 (c1) USING hash; Query OK, 0 rows affected (0.14 sec) Records: 0 Duplicates: 0 Warnings: 0 MariaDB [test]> SHOW WARNINGS; Empty set (0.00 sec) MariaDB [test]> SHOW INDEX FROM t5; +-------+------------+----------+--------------+-------------+-----------+------ -------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardi nality | Sub_part | Packed | Null | Index_type | Comment | +-------+------------+----------+--------------+-------------+-----------+------ -------+----------+--------+------+------------+---------+ | t5 | 1 | i1 | 1 | c1 | A | NULL | NULL | NULL | YES | BTREE | | +-------+------------+----------+--------------+-------------+-----------+------ -------+----------+--------+------+------------+---------+ 1 row in set (0.00 sec) MariaDB [test]>
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Launchpad bug id: 519691
There is IGNORE_BAD_TABLE_OPTIONS sql mode, which logically could apply here too.
But by default we do not "ignore bad table options" and this sql mode enables a relaxed behavior.
With indexes it's historically the opposite, the relaxed behavior is the default.
Suggestion: change the default to be strict and let IGNORE_BAD_TABLE_OPTIONS control it.
Re: No warning/error for unsupported index types
This is documented MySQL behaviour:
http://dev.mysql.com/doc/refman/5.1/en/create-index.html
"index_type"
"If you specify an index type that is not legal for a given storage engine, but there is another index type available that the engine can use without affecting query results, the engine uses the available type. "
On the other hand, if we receive a patch to generate a warning in this case, we might consider including it in MariaDB, as it seems a reasonable enough thing to do.