What is desperately needed here is indexing. shares.time should have an index, to avoid a table scan.
Actually shares.time is indexed already. Actually the table is over-indexed for such high transaction velocity. He needs help. I've offered my services via 3 days ago during the previous incident, no reply. I do this for a living and would appreciate a little more professionalism put into the backend.
So do it yourself, make a better pool, and we will switch to that. I'm working on having one made, I'm not a software dev myself, but I know a lot of really good ones. Unfortunately, this really isn't that much money for the amount of work and hassle it will be. You guys that keep posting about his making $3000 a day really aren't accounting for costs.
You could try out Multicoin
https://bitcointalk.org/index.php?topic=396063.0 .

Advertising aside, I see how h20 is having trouble managing a lot of it, as it is fast paced especially with the amount of hashrate he has.
Lots of coins being thrown around.
I think he was and still is doing a good job keeping everything running.