[support] slow site: db problems

[Karthik]

> Anyway, thinking furher about the indexing problem, I manually launched
> cron.php when iowait was 0,...%. When I did this, iowait went up to 70%,
> 80% and stayed very high (+50%). Restarting mysql brought it down to
> 0,...% again.
>
> So I'm thinking both problems may be connected: the broken search
> indexing and cron.php that causes iowait to go way up - and causing it
> to stay very high. We also see that there is a high load on mysql.

- Set up a MySQL slow query log on your test machine.

- OPTIMIZE all your tables.

- There is a setting on the search config page that allows you to
control the number of nodes indexed per cron run. Try reducing it.

- Try disabling the search module and run cron. If it isn't the search
module causing an issue, try disabling other modules .. ad nauseum.

etc. etc.