The performance data we are seeing indicate that the database is not effectively using the memory it has assigned. We see no significant difference, for instance, between performance of a machine with 8GB and one with 16GB of RAM. The idea here would be - basically - to force reuse of RAM for the database installation. A suggested implementation is given below:
Pros: Will likely reduce dependency on disk speed even further, since a large proportion of the queries hit the same OID's repeatedly.
Cons: Currently (Dec 2008), WDB appears to be CPU-bound for large workloads. Adding memcached does not solve these problems.