If I understand the manual correctly, it uses /tmp for creating temporary tables if their size exceed the smaller of tmp_table_size or max_heap_table_size, otherwise, it will create the temporary table in memory. So if tmp_table_size is set to say 10Mb, and MySQL needs to create a temporary table internally (which it does need for sorting and other stuff) which would be about 20Mb, it's going to create it in /tmp. If that temporary table had been 5Mb, it would have created it in memory.
I'm not sure how to calculate the needed space for /tmp. Check this for how to change the tmp directory location: http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_tmpdir Cheers, Amr On Thu, Jun 11, 2009 at 8:51 AM, Mike Spreitzer <mspre...@us.ibm.com> wrote: > I find my MySQL Community Edition 5.1.34 server running out of space on > /tmp (which is indeed small). Why is it using /tmp? How much free space > do I need on /tmp? Can/should I make the server use a different location > instead of /tmp? > > Thanks, > Mike Spreitzer >
