merlimat commented on issue #654: Do not delete inactive topics if they have 
retention policy
URL: https://github.com/apache/incubator-pulsar/pull/654#issuecomment-320966051
 
 
   > change LGTM. But quick question: if topic doesn't have subscribers and 
publishers, then why do we want to keep inactive topic till message-retention 
time?
   
   I can see multiple reasons : 
    * Consistency & semantic: If I configure the retention for 3h, I should 
have the data stored for (at least) 3h, irrespective of other conditions 
    * Retention is used primarily to be able to roll-back a consumer. Right now 
it's possible to create a subscription (at the end of the stream) and then roll 
it back to a earlier point in time, but only if there are already other 
subscriptions, otherwise the topic would have been deleted before.
    * Using the Reader API, the broker doesn't control the reader position, so, 
when a reader is gone it doesn't retain anything on the broker side. The reader 
relies on the retention for the data to be available and it's vital to not 
delete the topic before that time expires.
   
   
 
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


With regards,
Apache Git Services

Reply via email to