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

Håkon Alstadheim hakon at alstadheim.priv.no
Wed Jun 8 23:18:04 UTC 2016

Den 08. juni 2016 15:10, skrev Simon Hobson:
> Håkon Alstadheim <hakon at alstadheim.priv.no> wrote:
>> Mysqltuner complains about "Joins performed without indexes", but I do
>> not know enough mysql to start looking into that. Any hints ?
> Overall your values look reasonable - I assume you've already been tweaking them. But this one does stand out : "Query cache is disabled" - I assume that's not normal.
I believe I had the query cache up at 1.5 Gigs, with no noticeable
improvement. Found some guy saying that certain versions of MySQL saw no
benefit from query cache with certain specific usage. So, I tried
setting query cache to zero, and never looked back. There are much
better uses of ram in other parts of MySQL, like join buffer,
buffer_pool ...

More information about the mythtv-users mailing list