Hi Xiangying,
> In the current implementation, the backlog size is estimated from the > mark delete position to the last confirm position, whereas the backlog > message count is the number of messages from the mark delete position > to the last confirm position, minus the count of individually > acknowledged messages. The inconsistency between these two could > potentially confuse users. > While confusing, it is somewhat accurate. Since the messages can be part of the same ledger where some messages are acked, some aren't, we can't delete that entire ledger until all messages of the ledger are acked - so it does contribute towards size of the backlog from a disk perspective. There might be some optimization possible - in a way that we try to figure out all completely acked ledgers from markDeletePosition to latest offset and remove their size, but what's the ROI there? So I would say that in your proposal, option 2 (current) is more accurate (while not being the best) than option 1. Regards -- Girish Sharma
