MySQL Reference Manual :: A.2.12 Can't create/write to file

If you get an error of the following type for some queries, it means that MySQL cannot create a temporary file for the result set in the temporary directory:

Can't create/write to file '\\sqla3fe_0.ism'.

The preceding error is a typical message for Windows; the Unix message is similar.

One fix is to start mysqld with the --tmpdir option or to add the option to the [mysqld] section of your option file. For example, to specify a directory of C:\temp, use these lines:

[mysqld]
tmpdir=C:/temp

The C:\temp directory must exist and have sufficient space for the MySQL server to write to. See Section 4.3.2, “Using Option Files”.

Another cause of this error can be permissions issues. Make sure that the MySQL server can write to the tmpdir directory.

Check also the error code that you get with perror. One reason the server cannot write to a table is that the filesystem is full:

shell> perror 28
Error code  28:  No space left on device