[mythtv-users] 1/2 OT: MySQL with more than one tmpdir

[Thomas Boehm]

Raymond Wagner wrote:
> On 9/22/2013 11:20 AM, Thomas Boehm wrote:
>> Then
>> I want to create a tmpfs and want to use it for the tmpdir to speed up
>> MySQL a bit. But I have another large database, where 8GB would be too
>> small.
>
> MySQL doesn't store the whole database inside temporary tables. They
> are only used for certain types of internal processing, or in queries
> that specify the creation of a temporary table. Just because your
> database is over 8GB does not mean you actually need 8GB of temporary
> storage for it. You may need more. You will likely need much less.
>
> Temporary tables are only flushed to disk when they exceed the
> configured in-memory limit of the MySQL server. Rather than creating
> temporary storage out of memory, why not just let MySQL use more
> memory directly?

Ok, I should have written "and while repairing and optimizing" ;-)

I ran into problems in the past when I needed to repair a table/database
and it filled my /tmp partition. I think I needed twice the size of the
database. Or is "tmpdir" not used for optimizing and repairing and
instead the system's temp dir?