Hi Dong, I think your suggestion of including `Records` in the name of the new request and renaming `Fetch` and `Produce` to be `FetchRecords` and `ProduceRecords` is a good one. We can do the the renames separately. It's a compatible change since the name of the API is never exchanged with clients and the request/response classes are internal (we have done such renames before as Jason pointed out offline). The number of APIs will continue to grow and it will be much clearer if we avoid implicit assumptions about the target of an API request/response.
Given that, I also think that DeleteRecords makes sense since we also have DeleteTopics. Both are batch APIs that delete multiple items (the space is only freed later). If we use Oracle's definition of "purge", it seems to be what happens to cause the space to be freed (and happens in the background in Kafka): "Purging is the process of freeing up space in the database or of deleting obsolete data that is not required by the system. The purge process can be based on the age of the data or the type of data" https://docs.oracle.com/cd/E12057_01/doc.1014/e12050/archpurg.htm#BABHDECI Regarding the AdminClient, I thought the KIP was proposing adding this method to the Java AdminClient (KIP-117). If it's the Scala one, then it doesn't even need to be in the KIP as the Scala AdminClient is internal and no compatibility guarantees are offered (the methods that exist there never went through a KIP for example). So, I'm OK with keeping the method signature as it is. Ismael On Fri, Mar 10, 2017 at 6:06 PM, Dong Lin <lindon...@gmail.com> wrote: > Hey Jason, > > Just to clarify, are you, together with Ismael and Jeff, suggesting that > the new request should be named PurgeRecordsRequest instead of > PurgeRequest? The advantage of PurgeRecordsRequest is the name itself is > more explicit about what it does. The disadvantage of PurgeRecordsRequest > is that it is a bit consistent with ProduceRequest and FetchRequest, which > already assumes that if the target is not explicitly specified then the > target is "Records". > > I would be in favor of PurgeRecordsRequest if we plan to change > FetchRequest > to FetchRecordsRequest and ProduceRequest to ProduceRequestsRequest. > Otherwise, I would prefer PurgeRequest since it is more consistent with > existing style. Would PurgeRequest look more reasonable if we simply assume > that the operation target is "Records" if it is not explicitly specified in > the name? > > Becket is also in favor of PurgeRequest for the same reason. Maybe we can > start a vote for this if people can not reach consensus on this name? I > won't fight for PurgeRequest if most people like PurgeRecordsRequest. > > Thanks, > Dong > > > > > On Thu, Mar 9, 2017 at 5:39 PM, Jason Gustafson <ja...@confluent.io> > wrote: > > > Re; Purge vs PurgeRecords: I think I'm with Ismael and Jeff that the > > increasing surface area of the request APIs calls for more explicit > naming. > > PurgeRecords sounds reasonable to me. Using simple verbs like "fetch" and > > "produce" made sense when there were 6 or 7 APIs, but we'll soon be up to > > 30. I could also imagine having other Purge* APIs in the future (e.g. > > PurgeCommittedOffsets?), so it would be nice to avoid the need to rename > in > > the future, though it's probably not too big of a problem if we have to. > > (FWIW, I'd also be in favor of change FetchRequest to FetchRecordsRequest > > and ProduceRequest to ProduceRequestsRequest.) > > > > -Jason > > > > On Tue, Mar 7, 2017 at 10:11 AM, Dong Lin <lindon...@gmail.com> wrote: > > > > > Hi Jun, Ismael, > > > > > > I think making the API similar to a future KIP is desirable but not > > > required. Implementation is easy but discussion of the API may take a > lot > > > of time given that we haven't yet reached agreement on KIP-117. Thus I > > > prefer to just mark the API in Scala as unstable. > > > > > > I am OK with either delete or purge in the name. > > > > > > Thanks, > > > Dong > > > > > > > > > On Tue, Mar 7, 2017 at 9:59 AM, Jun Rao <j...@confluent.io> wrote: > > > > > > > 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 > > > > > > > > > >> > >> > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
