[mythtv-users] Bad mysql performance -- huge oldrecorded -- joins without index

Jeffrey Ratcliffe jeffrey.ratcliffe at gmail.com
Sat Jun 11 10:11:27 UTC 2016

On 9 June 2016 at 17:47, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> I think the general "best practice" (meaning guideline before
> profiling--which should always be performed before any efforts at
> optimization) says not to create an index on a temp table if you won't use
> the temp table and index at least twice.  While I haven't looked at the code
> in quite a while to be sure, I don't think we'd use the table/index twice.

Does this also imply that it is pointless increasing join_buffer_size
(the other suggestion from mysqltuner)?

What about table_open_cache ?



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