Hi, Dong, Ismael, 1. I just meant that it would be useful to distinguish between removing the whole log vs removing a portion of the log. The exact naming is less important.
4. When we move the purgeBefore() api to the Java AdminClient, it would be great if the api looks comparable to what's in KIP-117. For now, perhaps we can mark the api in Scala as unstable so that people are aware that it's subject to change? Thanks, Jun On Fri, Mar 3, 2017 at 11:25 AM, Dong Lin <lindon...@gmail.com> wrote: > Hey Ismael, > > Thank for the detailed explanation. Here is my thought: > > 1. purge vs. delete > > We have originally considered purge, delete, truncate and remove. I don't > have a strong preference among them and would be OK with any choice here. > That is why I didn't provide specific reasoning for selecting purge and > instead asked you and Jun for reason to choose between purge/delete. > > Can you be more specific where do we use "delete" in AdminClient.scala? I > couldn't find any usage of "delete" there. > > "delete" seems to be the only one that is exposed in the wire protocol and > script to the user. For example, "delete" as an option for kafka-topics.sh. > And it is used in the name of "DeleteTopicRequest" and a field name in the > StopReplicaRequest. That is why I slightly prefer "delete" over "purge". > > But all these names have been used in the Java API that is not exposed > directly to the user. For example, We have Log.truncateTo(), > DelayedOperation.purgeCompleted(), and MemoryNavigableLRUCache.remove(). > Also, we haven't yet exposed any Java API to user that uses any of these > choices. Thus there is no unanimous choice here and it should be OK to > choose any of the "delete", "purge", "truncate" or "remove" and at this > stage. I personally don't have any obvious difference among them and am OK > with any of them. > > 2. Message vs. Record vs. data in the Java API name. > > Both "message" and "record" are used in the Kafka, e.g. MemoryRecords, > ProducerRecord, ConsumerRecords, ReplicaManager.appendRecords(), > ReplicaManager.fetchMessages(). I remember there was a patch that changed > method name from using "message" to "record". Since Record is used more > widely, I think we should use Record instead of Message going forward. > > I agree that data is not used anyway and I prefer to change it to record, > e.g. purgeRecordBefore(). Does anyone have comment on this? > > > 3. PurgeRecordRequest vs. PurgeRequest > > As you said, PurgeRequest is consistent with FetchRequest and > ProduceRequest and it makes sense if we reserve the word > "Purge" for dealing with records/messages. I am not aware of anything other > than "record/message" that we may want to purge in the future. Even if > there is, I am not sure this would be an issue. For example, we can just > create PurgeXXXRequest similar to DeleteTopicsRequest. If we name the new > request ad PurgeRecordsRequest, it will be different from FetchRequest and > ProduceRequest which is probably more confusing to user. Thus I prefer to > keep the request name as PurgeRequest. > > > 4. Change method signature to encapsulate the parameters and result as does > in KIP-117. > > I don't think we should do it in KIP-107. First, KIP-117 is still under > discussion while KIP-107 has been reviewed for a few rounds and is almost > ready for commit. Changing the API at this moment will require more > discussion and delay progress. We should try to avoid that. Second, I think > it is OK for KIP-107 to have different API from KIP-117. The later KIP is > free to do what it wants and the earlier KIP should not depend on the later > KIP. User will need to change API anyway when they switch from Scala > AdminClient to Java AdminClient. > > Dong > > > On Fri, Mar 3, 2017 at 6:34 AM, Ismael Juma <ism...@juma.me.uk> wrote: > > > First of all, sorry to arrive late on this. > > > > Jun, do you have a reference that states that "purge" means to remove a > > portion? If I do "define: purge" on Google, one of the definitions is > > "physically remove (something) completely." > > > > In the PR, I was asking about the reasoning more than suggesting a > change. > > But let me clarify my thoughts. There are 2 separate things to think > about: > > > > 1. The protocol change. > > > > It's currently called Purge with no mention of what it's purging. This is > > consistent with Fetch and Produce and it makes sense if we reserve the > word > > "Purge" for dealing with records/messages. Having said that, I don't > think > > this is particularly intuitive for people who are not familiar with Kafka > > and its history. The number of APIs in the protocol keeps growing and it > > would be better to be explicit about what is being purged/deleted, in my > > opinion. If we are explicit, then we need to decide what to call it, > since > > there is no precedent. A few options: PurgeRecords, PurgeMessages, > > PurgeData, DeleteRecords, DeleteMessages, DeleteData (I personally don't > > like the Data suffix as it's not used anywhere else). > > > > 2. The AdminClient change. > > > > Regarding the name of the method, I'd prefer to avoid the `Data` suffix > > because I don't think we use that anywhere else (please correct me if I'm > > wrong). In the Producer, we have `send(ProduceRecord)` and in the > consumer > > we have `ConsumerRecords poll(...)`. So maybe, the suffix should be > > `Records`? Like in the protocol, we still need to decide if we want to > use > > `purge` or `delete`. We seem to use `delete` for all the other methods in > > the AdminClient, so unless we have a reason to use a different name, it > > seems like we should be consistent. > > > > The proposed method signature is `Future<Map<TopicPartition, > > PurgeDataResult>> purgeDataBefore(Map<TopicPartition, Long> > > offsetForPartition)`. In the AdminClient KIP (KIP-117), we are using > > classes to encapsulate the parameters and result. We should probably do > the > > same in this KIP for consistency. Once we do that, we should also > consider > > if `Before` should be in the method name or should be in the parameter > > class. Just an example to describe what I mean, one could say > > `deleteRecords(DeleteRecordsParams.before(offsetsForPartition)`. That > way, > > we could provide a different way of deleting by simply updating the > > parameters class. > > > > Some food for thought. :) > > > > Ismael > > > > > > > > On Thu, Mar 2, 2017 at 5:46 PM, Dong Lin <lindon...@gmail.com> wrote: > > > > > Hey Jun, > > > > > > Thanks for this information. I am not aware of this difference between > > the > > > purge and delete. Given this difference, I will prefer to the existing > > name > > > of the purge. > > > > > > Ismael, please let me if you are strong about using delete. > > > > > > Thanks, > > > Dong > > > > > > > > > On Thu, Mar 2, 2017 at 9:40 AM, Jun Rao <j...@confluent.io> wrote: > > > > > > > Hi, Dong, > > > > > > > > It seems that delete means removing everything while purge means > > > removing a > > > > portion. So, it seems that it's better to be able to distinguish the > > two? > > > > > > > > Thanks, > > > > > > > > Jun > > > > > > > > On Wed, Mar 1, 2017 at 1:57 PM, Dong Lin <lindon...@gmail.com> > wrote: > > > > > > > > > Hi all, > > > > > > > > > > I have updated the KIP to include a script that allows user to > purge > > > data > > > > > by providing a map from partition to offset. I think this script > may > > be > > > > > convenience and useful, e.g., if user simply wants to purge all > data > > of > > > > > given partitions from command line. I am wondering if anyone object > > > this > > > > > script or has suggestions on the interface. > > > > > > > > > > Besides, Ismael commented in the pull request that it may be better > > to > > > > > rename PurgeDataBefore() to DeleteDataBefore() and rename > > PurgeRequest > > > to > > > > > DeleteRequest. I think it may be a good idea because > kafka-topics.sh > > > > > already use "delete" as an option. Personally I don't have strong > > > > > preference between "purge" and "delete". I am wondering if anyone > > > object > > > > to > > > > > this change. > > > > > > > > > > Thanks, > > > > > Dong > > > > > > > > > > > > > > > > > > > > On Wed, Mar 1, 2017 at 9:46 AM, Dong Lin <lindon...@gmail.com> > > wrote: > > > > > > > > > > > Hi Ismael, > > > > > > > > > > > > I actually mean log_start_offset. I realized that it is a better > > name > > > > > > after I start implementation because "logStartOffset" is already > > used > > > > in > > > > > > Log.scala and LogCleanerManager.scala. So I changed it from > > > > > > log_begin_offset to log_start_offset in the patch. But I forgot > to > > > > update > > > > > > the KIP and specify it in the mailing thread. > > > > > > > > > > > > Thanks for catching this. Let me update the KIP to reflect this > > > change. > > > > > > > > > > > > Dong > > > > > > > > > > > > > > > > > > On Wed, Mar 1, 2017 at 6:15 AM, Ismael Juma <ism...@juma.me.uk> > > > wrote: > > > > > > > > > > > >> Hi Dong, > > > > > >> > > > > > >> When you say "logStartOffset", do you mean "log_begin_offset "? > I > > > > could > > > > > >> only find the latter in the KIP. If so, would log_start_offset > be > > a > > > > > better > > > > > >> name? > > > > > >> > > > > > >> Ismael > > > > > >> > > > > > >> On Tue, Feb 28, 2017 at 4:26 AM, Dong Lin <lindon...@gmail.com> > > > > wrote: > > > > > >> > > > > > >> > Hi Jun and everyone, > > > > > >> > > > > > > >> > I would like to change the KIP in the following way. > Currently, > > if > > > > any > > > > > >> > replica if offline, the purge result for a partition will > > > > > >> > be NotEnoughReplicasException and its low_watermark will be 0. > > The > > > > > >> > motivation for this approach is that we want to guarantee that > > the > > > > > data > > > > > >> > before purgedOffset has been deleted on all replicas of this > > > > partition > > > > > >> if > > > > > >> > purge result indicates success. > > > > > >> > > > > > > >> > But this approach seems too conservative. It should be > > sufficient > > > in > > > > > >> most > > > > > >> > cases to just tell user success and set low_watermark to > minimum > > > > > >> > logStartOffset of all live replicas in the PurgeResponse if > > > > > >> logStartOffset > > > > > >> > of all live replicas have reached purgedOffset. This is > because > > > for > > > > an > > > > > >> > offline replicas to become online and be elected leader, it > > should > > > > > have > > > > > >> > received one FetchReponse from the current leader which should > > > tell > > > > it > > > > > >> to > > > > > >> > purge beyond purgedOffset. The benefit of doing this change is > > > that > > > > we > > > > > >> can > > > > > >> > allow purge operation to succeed when some replica is offline. > > > > > >> > > > > > > >> > Are you OK with this change? If so, I will go ahead to update > > the > > > > KIP > > > > > >> and > > > > > >> > implement this behavior. > > > > > >> > > > > > > >> > Thanks, > > > > > >> > Dong > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > On Tue, Jan 17, 2017 at 10:18 AM, Dong Lin < > lindon...@gmail.com > > > > > > > > wrote: > > > > > >> > > > > > > >> > > Hey Jun, > > > > > >> > > > > > > > >> > > Do you have time to review the KIP again or vote for it? > > > > > >> > > > > > > > >> > > Hey Ewen, > > > > > >> > > > > > > > >> > > Can you also review the KIP again or vote for it? I have > > > discussed > > > > > >> with > > > > > >> > > Radai and Becket regarding your concern. We still think > > putting > > > it > > > > > in > > > > > >> > Admin > > > > > >> > > Client seems more intuitive because there is use-case where > > > > > >> application > > > > > >> > > which manages topic or produces data may also want to purge > > > data. > > > > It > > > > > >> > seems > > > > > >> > > weird if they need to create a consumer to do this. > > > > > >> > > > > > > > >> > > Thanks, > > > > > >> > > Dong > > > > > >> > > > > > > > >> > > On Thu, Jan 12, 2017 at 9:34 AM, Mayuresh Gharat < > > > > > >> > > gharatmayures...@gmail.com> wrote: > > > > > >> > > > > > > > >> > >> +1 (non-binding) > > > > > >> > >> > > > > > >> > >> Thanks, > > > > > >> > >> > > > > > >> > >> Mayuresh > > > > > >> > >> > > > > > >> > >> On Wed, Jan 11, 2017 at 1:03 PM, Dong Lin < > > lindon...@gmail.com > > > > > > > > > >> wrote: > > > > > >> > >> > > > > > >> > >> > Sorry for the duplicated email. It seems that gmail will > > put > > > > the > > > > > >> > voting > > > > > >> > >> > email in this thread if I simply replace DISCUSS with > VOTE > > in > > > > the > > > > > >> > >> subject. > > > > > >> > >> > > > > > > >> > >> > On Wed, Jan 11, 2017 at 12:57 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/confl > > uence/display/KAFKA/KIP-107 > > > > > >> > >> > > %3A+Add+purgeDataBefore%28%29+API+in+AdminClient. > > > > > >> > >> > > > > > > > >> > >> > > Thanks, > > > > > >> > >> > > Dong > > > > > >> > >> > > > > > > > >> > >> > > > > > > >> > >> > > > > > >> > >> > > > > > >> > >> > > > > > >> > >> -- > > > > > >> > >> -Regards, > > > > > >> > >> Mayuresh R. Gharat > > > > > >> > >> (862) 250-7125 > > > > > >> > >> > > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > >
