Hi, Cong IMO, Please do not break the previous directly. We can migrate it smoothly. We can add a configuration and give the Timeline of making this configuration default and removing it in the next release version.
For example: - Add configuration: `compactionRemainNullKey=true` by default (current behaviour) - Make `compactionRemainNullKey=false` default in the 3.2.0 - Delete the configuration `compactionRemainNullKey` in 3.3.0. This approach will avoid breaking changes and give our users enough time to migrate their usage. Plus, I think it’s fair to cherry-pick it to all the previous active branches. Thanks! Mattison > On Nov 7, 2023, at 10:55, Cong Zhao <zhaoc...@apache.org> wrote: > > Hi, Pulsar community > > Currently, we retain all null-key messages during topic compaction, which I > don't think is necessary because when you use topic compaction, > it means that you want to retain the value according to the key, so > retaining null-key messages is meaningless. > > Additionally, retaining all null-key messages will double the storage cost, > and we'll never be able to clean them up since the compacted topic has not > supported the retention policy yet. > > In summary, I don't think we should retain null-key messages during topic > compaction. > Looking forward to your feedback! > > Thanks, > Cong Zhao