Hi, If you are worried about old state, you can combine the compaction filter based TTL with other cleanup strategies (see docs). For example, setting `cleanupFullSnapshot` when you take a savepoint it will be cleared of any expired state and you can then use it to bring it into Flink 1.8.
Best, Stefan > On 13. Mar 2019, at 13:41, Ning Shi <nings...@gmail.com> wrote: > > Just wondering if anyone has any insights into the new TTL state cleanup > feature mentioned below. > > Thanks, > > — > Ning > > On Mar 11, 2019, at 1:15 PM, Ning Shi <nings...@gmail.com > <mailto:nings...@gmail.com>> wrote: > >> It's exciting to see TTL state cleanup feature in 1.8. I have a question >> regarding the migration of existing TTL state to the newer version. >> >> Looking at the Pull Request [1] that introduced this feature, it seems like >> that Flink is leveraging RocksDB's compaction filter to remove stale state. >> I assume this means that state will only be cleaned on compaction. If I have >> a significant amount of stale TTL state, some of which may have already been >> compacted to higher levels already, upgrading to 1.8 may not clean them. Is >> this assumption correct? If so, is the best approach to take a full >> snapshot/checkpoint and restore it to 1.8 to have them been cleaned on >> initialization? >> >> Thanks, >> >> [1] https://github.com/dataArtisans/frocksdb/pull/1 >> <https://github.com/dataArtisans/frocksdb/pull/1> >> >> -- >> Ning
