Hi, Dong, For 2(b), it seems a bit weird to allow highWatermark to be smaller than lowWatermark. Also, from the consumer's perspective, messages are available only up to highWatermark. What if we simply throw OffsetOutOfRangeException if offsetToPurge is larger than highWatermark?
Thanks, Jun On Tue, Jan 17, 2017 at 9:54 PM, Dong Lin <lindon...@gmail.com> wrote: > Hi Jun, > > Thank you. Please see my answers below. The KIP is updated to answer these > questions (see here > <https://cwiki.apache.org/confluence/pages/diffpagesbyversion.action? > pageId=67636826&selectedPageVersions=5&selectedPageVersions=6> > ). > > 1. Yes, in this KIP we wait for all replicas. This is the same as if > producer sends a messge with ack=all and isr=all_replicas. So it seems that > the comparison is OK? > > 2. Good point! I haven't thought about the case where the user-specified > offset > logEndOffset. Please see answers below. > > a) If offsetToPurge < lowWatermark, the first condition > of DelayedOperationPurgatory will be satisfied immediately when broker > receives PurgeRequest. Broker will send PurgeResponse to admin client > immediately. The response maps this partition to the lowWatermark. > > This case is covered as the first condition of DelayedOperationPurgatory in > the current KIP. > > b) If highWatermark < offsetToPurge < logEndOffset, leader will send > FetchResponse with low_watermark=offsetToPurge. Follower records the > offsetToPurge as low_watermark and sends FetchRequest to the leader with > the new low_watermark. Leader will then send PurgeResponse to admin client > which maps this partition to the new low_watermark. The data in the range > [highWatermark, offsetToPurge] will still be appended from leader to > followers but will not be exposed to consumers. And in a short period of > time low_watermark on the follower will be higher than their highWatermark. > > This case is also covered in the current KIP so no change is required. > > c) If logEndOffset < offsetToPurge, leader will send PurgeResponse to admin > client immediately. The response maps this partition to > OffsetOutOfRangeException. > > This case is not covered by the current KIP. I just added this as the > second condition for the PurgeRequest to be removed from > DelayedOperationPurgatory (in the Proposed Change section). Since the > PurgeRequest is satisfied immediately when the leader receives it, it > actually won't be put into the DelayedOperationPurgatory. > > 3. Yes, lowWatermark will be used when smallest_offset is used in the > ListOffsetRequest. I just updated Proposed Change section to specify this. > > Thanks, > Dong > > On Tue, Jan 17, 2017 at 6:53 PM, Jun Rao <j...@confluent.io> wrote: > > > Hi, Dong, > > > > Thanks for the KIP. Looks good overall. Just a few more comments. > > > > 1."Note that the way broker handles PurgeRequest is similar to how it > > handles ProduceRequest with ack = -1 and isr=all_replicas". It seems that > > the implementation is a bit different. In this KIP, we wait for all > > replicas. But in producer, acks=all means waiting for all in-sync > replicas. > > > > 2. Could you describe the behavior when the specified offsetToPurge is > (a) > > smaller than lowWatermark, (b) larger than highWatermark, but smaller > than > > log end offset, (c) larger than log end offset? > > > > 3. In the ListOffsetRequest, will lowWatermark be returned when the > > smallest_offset option is used? > > > > Thanks, > > > > Jun > > > > > > On Wed, Jan 11, 2017 at 1:01 PM, Dong Lin <lindon...@gmail.com> wrote: > > > > > Hi all, > > > > > > It seems that there is no further concern with the KIP-107. At this > point > > > we would like to start the voting process. The KIP can be found at > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-107 > > > %3A+Add+purgeDataBefore%28%29+API+in+AdminClient. > > > > > > Thanks, > > > Dong > > > > > >
