Re: MySQL 5.5 Queries occasionally extremely slow

[Rick James]

> WHERE latitude != '0.000000' AND activedate >= inactivedate

What percentage of the rows are filtered out by tose conditions?
Consider removing the rows that are not relevant.

> Group By Projects.ProjectID
> ORDER BY Projects.ProjectID ASC, source.sort_order ASC

The GROUP BY ends up with unique values for ProjectID, so the second part of the ORDER BY never does anything extra.

> LIMIT 30000

Is that a realistic limit? What happens if you take off the limit?

> SELECT lots of stuff
> Group By Projects.ProjectID

Do you understand that you get random values for the stuff that is not tied directly to ProjectID?

Or are you doing the GROUP BY just in case some of the JOINs generate multiple rows?

Since you have a GROUP_CONCAT(), I guess you are expecting multiple rows, but from which table?

If the GROUP_CONCAT() is coming from just one table, then this _might_ run faster:
SELECT ...
( SELECT GROUP_CONCAT FROM ... WHERE ... GROUP BY ... ) AS images_list,
...
then remove the relavant JOIN and outer GROUP BY.

Please, please, tag each field with an alias of the table it belongs to. It is hard to know what is coming from where. Also, shorter aliases help reduce clutter.

Please provide SHOW CREATE TABLEs.