-Unlike the B-trees, where you only need to touch one data page to find an entry
-of interest, doing an index lookup generally touches multiple keys, and the
-point of a hash structure is that the keys are evenly distributed across the
-data space. That means there's no convenient compact subset of the database that
-you can keep in the cache to insure quick operation, you can pretty much expect
-references to be scattered across the whole thing. My strategy here would be to
-provide enough cache for at least 50% of all of the hash data.
+For example, if your only index is for the objectClass attribute and db_stat
+reveals that {{objectClass.bdb}} has 339 internal pages and uses 4096 byte
+pages, the additional cache needed for just this attribute index is