Major Description
When migrating consumer offsets from ZooKeeper to kafka, we have to turn on dual-commit (i.e., the consumers will commit offsets to both zookeeper and kafka) in addition to setting offsets.storage to kafka. However, when we commit offsets we only commit offsets if they have changed (since the last commit). For low-volume topics or for topics that receive data in bursts offsets may not move for a long period of time. Therefore we may want to force the commit (even if offsets have not changed) when migrating (i.e., when dual-commit is enabled) - we can add a minimum interval threshold (say force commit after every 10 auto-commits) as well as on rebalance and shutdown.
Also, I think it is safe to switch the default for offsets.storage from zookeeper to kafka and set the default to dual-commit (for people who have not migrated yet). We have deployed this to the largest consumers at linkedin and have not seen any issues so far (except for the migration caveat that this jira will resolve).