why the table of information_schema is damaged?

Question

I want to get information from COLUMNS of information_schema. I execute the following command:

root:information_schema> select * from COLUMNS;

but it occur the error：

ERROR 126 (HY000): Incorrect key file for table '/tmp/#sql_11b6_0.MYI'; try to repair it

So I want to repair the table. I execute the following command:

root:information_schema> repair table COLUMNS;

but it occur error again,the wrong content follow：

ERROR 1044 (42000): Access denied for user 'root'@'localhost' to database 'information_schema'

I don't why the root user have no privileges to repair the table

Answer 1

When you see something like '/tmp/#sql_XXXXX_X.MYI', the problem is your file system is full and the temporary file needing to be created can't be written to. Remove any unnecessary files and try again.