Hi Gang,

Thank you for the information, that is helpful for understanding the
overall design and implementation.

Do you have some statistical information, like performance, throughput,
stability, etc.? Besides, what's the plan of contributing it to the
community? Thanks!


Ma Gang <mg4w...@163.com> 于2018年11月1日周四 下午2:45写道:

> Thanks Xiaoxiang,
> Very good questions! Please see my comments started with [Gang]:
>
>
> 1.      Is it possible to use Yarn as cluster manager for index task.
> Coordinator process will set up them at specificed period.
> [Gang] I think it is possible, but in current design,  the indexing task
> is designed as long running task, it also can provide query service, this
> makes the whole system very simple and efficiency, I don't think we need to
> stop/start indexing task time by time. But use yarn to manage the resource
> is possible, we need to redesign the existing coordinator, to make it easy
> to deploy to Yarn, Kubernetes, etc. Hope this can be done after
> contribution to community.
>
> 2.      As I know, ebay’s New Kylin Streaming Solution use replica Set to
> ensure that income messages wouldn’t lost if some processes  lost. I think
> replica set is a set of kafka cosumer processes which is responsible for
> ingest message and build base cuboid in memory. Could you please show me
> some detail about how replica Set provide HA guarantee? How to configure
> it? A link / paper is OK.  I found one but I don’t know if it same meaning
> for your replica Set.
>
>
> [Gang] Yes, it is similar as the MongoDB replication, but currently we
> don't replicate data from Primary node, just assign the same Kafka
> topic/partitions to the receivers in a ReplicaSet, all receivers in a
> ReplicaSet will consume data from Kafka, so if one receiver is down, other
> receivers in the ReplicaSet are still consuming the same Kafka data, so the
> consume/query will not be impact. And We don't guarantee that the receivers
> in a ReplicaSet have the same consuming rate, but we can guarantee that the
> user can view data consistently by stick to the query to one receiver for
> one cube.
> The HA implementation is a little bit naive, but simple and worked. Maybe
> in the future, we can do HA by replication to support other streaming
> sources that don't support multiple consumers and don't have persistent
> store.
>
> 3.      How to add or remove node of replica Set in production env? How to
> monitor the health/pressure of replica Set cluster ?
> [Gang] Currently we have UI/restful api to let admin to add/remove node
> to/from a ReplicaSet, and have a simple ui to let admin monitor the health,
> consuming rate for each receiver/cube. Also all metrics are collected using
> yammer metrics framework, it is easy to exposed to other monitor system.
>
> 4.      Does all measure are supported in ebay’s New Kylin Streaming
> Solution? What about count distinct(bitmap)?
> [Gang] Most measures are supported, but precise count distinct(bitmap) is
> not support in case that the distinct dimension is not int type. As you
> know, to support precise count distinct for not-int type dimension, it
> needs to build global dictionary, it is not possible in the streaming env.
>
>
> 5.      It seems ebay’s New Kylin Streaming Solution use a custom columnar
> storage, why not use a open source mature columnar storage  solution ? Have
> your ever compare the performance of your custom columnar storage to open
> source columnar storage  solution ?
>
> [Gang] Most open source columnar format like Parquet, ORC are designed to
> use in Hadoop env, the streaming data are in local disk, so I didn't
> consider them at the beginning. It is not very hard to define columnar
> format to store Kylin specific data, use a customize columnar storage, you
> can use mmap file to scan data, add row-level invert index for all
> dimensions, so I think the performance will be better compared to using
> common columnar format. I didn't compare the performance, but the storage
> engine is pluggable, you may contribute a parquet storage if you are
> interesting.
>
>
>
>
>
>
> At 2018-11-01 12:42:25, "Xiaoxiang Yu" <xiaoxiang...@kyligence.io> wrote:
> >Hi gang, I am so glad to know that eBay has a solution for realtime olap
> on kylin. I have some small question:
> >
> >
> >1.      Is it possible to use Yarn as cluster manager for index task.
> Coordinator process will set up them at specificed period. Yarn will manage
> :
> >
> >a)       retry these task if some failed
> >
> >b)       resource allocation
> >
> >c)       log collection
> >
> >2.      As I know, ebay’s New Kylin Streaming Solution use replica Set to
> ensure that income messages wouldn’t lost if some processes  lost. I think
> replica set is a set of kafka cosumer processes which is responsible for
> ingest message and build base cuboid in memory. Could you please show me
> some detail about how replica Set provide HA guarantee? How to configure
> it? A link / paper is OK.  I found one but I don’t know if it same meaning
> for your replica Set.
> >
> >a)       [Mongodb replication](
> https://docs.mongodb.com/manual/replication/).
> >
> >3.      How to add or remove node of replica Set in production env? How
> to monitor the health/pressure of replica Set cluster ?
> >
> >4.      Does all measure are supported in ebay’s New Kylin Streaming
> Solution? What about count distinct(bitmap)?
> >
> >5.      It seems ebay’s New Kylin Streaming Solution use a custom
> columnar storage, why not use a open source mature columnar storage
> solution ? Have your ever compare the performance of your custom columnar
> storage to open source columnar storage  solution ?
> >
> >
> >
> >----------------
> >Best wishes,
> >Xiaoxiang Yu
> >
> >
> >发件人: Ma Gang <mg4w...@163.com>
> >答复: "dev@kylin.apache.org" <dev@kylin.apache.org>
> >日期: 2018年10月30日 星期二 15:24
> >收件人: "dev@kylin.apache.org" <dev@kylin.apache.org>
> >主题: [DISCUSS] New Kylin Streaming Solution From eBay
> >
> >Hi all,
> >
> >eBay Kylin team has developed a new Kylin streaming solution, the basic
> idea is to build a streaming cluster to ingest data from streaming
> source(Kafka), and provide query for real-time data, the data preparation
> latency is milliseconds, which means the data is queryable almost when it
> is ingested, attach is the architecture design doc.
> >We would like to contribute the feature to community, please let us know
> if you have any concern.
> >
> >Thanks,
> >Gang(Allen) Ma
> >
> >
> >
> >
> >
>


-- 
Best regards,

Shaofeng Shi 史少锋

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