Andrii, 404. Jay and I chatted a bit. We agreed to leave createTopicRequest as async for now.
There is another thing. 500. Currently, we have this issue (KAFKA-1367) that the ISR in the metadata cache can be out of sync. The reason is that ISR is really maintained at the leader. We can potentially add a new BrokerMetaRequest, which will return useful stats specific to a broker. Such stats can include (1) for each partition whose leader is on this broker, the ISR and the lag (in messages) for each of the followers, (2) space used per partition, (3) remaining space per log dir (not sure how easy it is to get this info). If we have this new request, we can probably remove the ISR part from TMR v1. Currently, the producer/consumer client don't really care about ISR. The admin client will then issue BrokerMetaRequest to find out ISR and other stats. Thanks, Jun On Tue, Apr 7, 2015 at 12:10 PM, Andrii Biletskyi < andrii.bilets...@stealth.ly> wrote: > Hi all, > > A summary of our discussion: > > 201. Q: Cluster updates in backward compatible way. > A: Add topicConfigs map property and change constructor, this > shouldn't break Consumer/Producer since TMR is used in NetworkClient, > not directly by Consumer/Producer. > > 300. Q: Can we merge AlterTopic and ReassignPartitions requests? > A: It looks like in terms of Wire Protocol partition reassignment > can > be just an application of AlterTopicRequest. On the AdminClient side we can > split this into two separate methods, if needed. > > Some additional items that were added today: > 400. Q: Do we need ListTopicsRequest, we can use TMR for this purpose. > A: The answer depends on whether we can leverage ListTopics in > consumer/producer, because the only benefit of the ListTopics is > performance > optimization, otherwise it doesn't worth it. > > 401. Q: AdminClient.topicExists - do we need it? > A: AdminClient.listTopics should be sufficient. > > 402. Review AdminClient API and use separate objects instead of collections > for methods arguments / return results (e.g. preferredReplica accepts > Map<String, List<Int>> > might be better to add separate java object) > > 403. Error number in KIP-4 (100x). Currently there are no dedicated ranges > for errors, we will probably continue doing it this way. > > 404. There were some concerns again about the asynchronous semantics > of the admin requests. Jun and Jay to agree separately how we want > to handle it. > > Please add / correct me if I missed something. > > Thanks, > Andrii Biletskyi > > On Tue, Apr 7, 2015 at 4:11 PM, Andrii Biletskyi < > andrii.bilets...@stealth.ly> wrote: > > > Hi all, > > > > I wasn't able to send email to our thread (it says we exceeded message > > size limit :)). > > So I'm starting the new one. > > > > > > Jun, > > > > Thanks again for the review. Answering your comments: > > > > 201. I'm not sure I understand how can we evolve Cluster in backward > > compatible way. In my understanding topic configs are not returned > > currently - > > in TMR_V0. Thus we need to add new property in Cluster - smth like > > private final Map<String, List<ConfigEntry>> topicConfigs; > > Which affects Cluster constructor, which is used in MetadataResponse.java > > - not sure whether we can change Cluster this way so it's backward > > compatible, > > I suppose - no. > > Let me know if I'm missing something... > > > > 300. Hm, so you propose to give up ReassignPartition as a separate > command? > > That's interesting, let's discuss it today in detail. > > Two small points here: 1) afaik currently replica-assignment argument in > > alter-topic > > (from TopicCommand) doesn't reassign partitions, it lets users specify > > replica > > assignment for newly added partition (AddPartitionsListener) 2) > > ReassignPartitions > > command involves a little bit more than just changing replica assignment > > in zk. > > People are struggling with partition reassignment so I think it's good to > > have explicit > > request for it so we can handle it independently, also as mentioned > > earlier we'll > > probably add in future some better status check procedure for this > > long-running > > request. > > > > 301. Good point. We also agreed to use clientId as an identifier for the > > requester - > > whether it's a producer client or admin. I think we can go with -1/-1 > > approach. > > > > 302. Again, as said above replica-assignment in alter-topic doesn't > change > > replica assignment of the existing partitions. But we can think about it > > in general - > > how can we change topic replication factor? The easy way - we don't need > > it, > > we can use reassign partitions. Not sure whether we want to add special > > logic > > to treat this case... > > > > 303.1. Okay, sure, I'll generalize topicExists(). > > 303.2. I think, yes, we need separate verify methods as a status check > > procedure, > > because respective requests are long running, and CLI user potentially > > will > > asynchronously call reassign-partitions, do other stuff (e.g. create > > topics) periodically > > checking status of the partition reassignment. Anyway we'll have to > > implement this logic > > because it's a criterion of the completed Future of the reassign > > partitions async > > call, we'll to have make those methods just public. > > 303.3. If preferredReplica returns Future<Map<String, Errors>> than what > > is an error > > in terms of preferred replica leader election? As I understand we can > only > > check > > whether it has succeeded (leader == AR.head) or not _yet_. > > > > 304.1. Sure, let's add timeout to reassign/preferred replica. > > 304.2. This can be finalized after we discuss 300. > > > > 305. Misprints - thanks, fixed. > > > > Thanks, > > Andrii Biletskyi > > >
