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- Optimize memory footprint after every upgrade step. [jone]
- Reduce memory footprint in SavepointIterator by garbage-collecting connection cache. [jone]
- Set the default savepoint threshold to 1000; make it configurable. [jone]
- Enable savepoint iterator by default. Affects ``self.objects``. [jone]
- Use a SavepointIterator in the WorkflowSecurityUpdater in order not to exceed
memory. [mbaechtold]