Like I said in OP, we've identified MySQL to be the primary bottleneck and are already working on resolving this.
>whose transactions are abandoned.
At least some saving grace here... we're not selling anything... it is purely a content site
Thanks for your input.
Ah, yes. I remember from your prior post that you have very large databases and table sizes and are considering (or have begun) partitioning the largest tables. It turns out there is an innate partitioning scheme built into the most recent MySQL versions, but it has to be compiled into the running binary by way of a compiler flag:
http://dev.mysql.com/doc/refman/5.1/en/partitioning.html
I apologize if you've already heard this, or if it's already in place as a partial solution.
Perhaps, it is time for us to revisit this. Thanks again Paul.
You need to examine the restart process and analyze why it resolves the issue. If the reason is the abandonment of dead parasitic processes and memory leaks, you need to find out why and correct them. If the reason is that the restart unceremoniously drops all the current transactions, you need to increase capacity.
> Can anyone think of any downside to this (used at least as a temporary measure)?
I certainly can -- a bunch of really irritated visitors, whose transactions are abandoned. But that's only true if that is actually what's going on. Make sure you don't have software issues that are preventing efficient operation. If that's not the issue, you need to grow with your customer base -- increase server capacity.