index – MySQL: message “Incorrect key file for table” “try to repair it”

I’m using MySQL 5.7.10

I have a table like this, with 100M rows and a size of 16GB .

CREATE TABLE `my_table` (
    `id` DOUBLE NOT NULL AUTO_INCREMENT,
    `entity_id` DOUBLE NOT NULL,
    `concept_id` VARCHAR(50) NOT NULL COLLATE 'utf8_spanish_ci',
    `value` DOUBLE(15,6) NOT NULL,
    `increment` DOUBLE(10,6) NULL DEFAULT NULL,
    PRIMARY KEY (`id`),
    INDEX `IDX_concept` (`concept_id`),
    INDEX `IDX_entity` (`entity_id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
ROW_FORMAT=DYNAMIC
AUTO_INCREMENT=118166425

Once a month, I execute:

ALTER TABLE my_table ENGINE=InnoDB;

My intention is to defrag the table, so the data are put together and the size keeps as low as possible.

This time, it failed and the failure message is: “Incorrect key file for table ‘my_table’; try to repair it”.

I have made the following steps:

1. Create a table like this: my_table2.
2. Use mysqldump to dump my_table data in a file.
3. Replace the create and the inserts to be done in “my_table2”.
4. Execute the file. my_table2 is created and each row in my_table exists in my_table2.
5. Execute ALTER TABLE my_table2 ENGINE=InnoDB;

And it failed too, with the same message “Incorrect key file for table ‘my_table2’; try to repair it”.

How could I fix the error? Thank you.

EDIT 1: I have executed CHECK TABLE for both tables, and the result is status OK, for both of them.