hozumi commented on issue #7500: URL: https://github.com/apache/pulsar/issues/7500#issuecomment-667083124
https://youtu.be/PIX570nyq_c?t=738 Thank you for describing backlog and retention clearly. I think that it is very helpful if the above explanation is included in document. Adding a note for my previous understanding. For later created subscription to consume all retained messages, the backlog quota should be set to more than current retained size. On maximum storage size estimation: > Does the above document mean that while the messages in the consumer's backlog are not deleted by the retention policy settings, but all messages including acknowledged and unacknowledged are included to calculate the size limit of the retention policy? > If so, it make sense. I can easily manage maximum disk space only by retention policy and write_quorum_size. This is wrong. ``` #6 Backlog quota sets a CAP on unacked messages. #8 Retention Policy defines how to handle acked messages. Storage Size = Backlog Size + Retained Messages Size ``` (from the video above) Considering unacknowledged messages, the maximum storage size should be estimated by (the size of backlog quota + the size of the retention policy) * write_quorum_size, not simply by the size of the retention policy * write_quorum_size. (I ignored segment thing for simplicity. Actual storage size will be sum of underlying segment.) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
