Get and Put performance testing on Google BigTables (and other integrated DBs)

What are some effective ways to perform programmatic performance testing on database operations, especially in environments where the databases themselves do not offer dedicated tools? For example, in Google App Engine, entire page-loads are evaluated as one operation which may include specific database operations. This problem is also likely present in SQLite and other integrated DBs. As it is difficult to completely abstract the (equivalent of) selects and inserts that need to be tested, are there any recommended database tools to perform more thorough diagnostics on these sorts of queries?