Saxon

The fix to bug #1968 introduced a performance regression for keys where the key definition references global variables or user-defined functions. Indexes for such keys are no longer held globally, because the index (and the result of using it) can depend on per-transformation data such as global stylesheet parameters. Instead they are held at the level of the Controller. But such local indexes are not being properly cached for the duration of a transformation and are therefore built repeatedly rather than being reused. Test case key-089 illustrates the problem.