Hi, all
Leaving aside this feature, has the PR of the big feature we merged in been discussed in detail? How to define detailed discussion? I think that we should discuss some of our discussion points clearly at the beginning of the design, instead of how to revert the PR after the PR is merged. I think there is a problem with this process. Who can guarantee that there are no bugs and no problems in the developed functions, and we are all improving through continuous iteration. And this feature also refers to the design of some other excellent projects, such as doris and hbase. As for the name of this feature, in doris, it is called multi-tenancy[1], in hbase it is called quota[2], we can call it resource-control, I think it is ok. After all, we did not reflect the wording of multi-tenancy in the code implementation. [1] https://doris.apache.org/docs/dev/admin-manual/multi-tenant [2] https://hbase.apache.org/book.html#quota Thanks, --------------------------------------- Houliang Qi BONC, Ltd ---- Replied Message ---- | From | Chao Wang<[email protected]> | | Date | 04/11/2023 09:15 | | To | [email protected]<[email protected]> | | Cc | [email protected]<[email protected]> | | Subject | Re: [discuss] consider revert the feature of multi-tenancy | Hi, Xiangdong, what is the side effect when we manually create a time series? How about the pr https://github.com/apache/iotdb/pull/9430, limit the timeseries number of cluster, anyone analyze the side effect about creating a time series? This discuss is not for getting "+1" or "-1" (though anyone can reply the vote..). I just want to discuss that do we REALLY consider and analyze the feature and the implementation carefully? Why not discuss before the PR submission, but wait until the PR submission before discussing, wouldn't it waste the energy of community participants? I have also seen emails sent before, not without notifying everyone. In addition, I think Jialin's suggestion is more reasonable. The description of this function may not be particularly clear. It can be said in another way, such as resource control. However, reverting will undoubtedly be harmful to the community, will discourage the enthusiasm of community participants, and is very unfriendly to community participants. If in doubt, I think it would be better to raise it as soon as possible, instead of waiting for others to finish their hard work before questioning. Another point is that the multi-tenancy function may be a function required by other companies' IOTDB releases, but will other people's contributions to the community affect the development of the community? I think it will be more conducive to the development of community diversity. Thanks! Chao Wang BONC ltd [email protected] On 4/10/2023 23:45，Xiangdong Huang<[email protected]> wrote： Besides the above, when we merge this pr, we posted the design in the feishu[4] and discussed it online as least two times, and emailed and discussed it with everyone[5], it has been passed 10 days. I think I know this and I have shown my concern about the possible harm of this featuer to IoTDB's edge mode... 1) how many side-effects the feature will bring; We have done some tests under[1], which says with 20 databases and 1 user when we set `quota_enable` to true to enable the multi-tenancy feature, the write performance is only slowed down 1.75%, the read latency has not much difference, we will do more tests to show the side-effects in the feature. The experiment is rather simple... When we really want to show the added codes having no side-effects, all the exepriemnt settings should follow a rule that how to fully expose the possible problems. For example, as mult-tenancy limits the available # of devices, timeseries, and the spaces of disk, it should have side-effect on create new device/timeseries, and writing new data. So, - what is the side effect when we manually create a time series? - what is the side effect when we use automatical creating a time series? - what is the side effect when we write new data? (as the data can be compressed when it is flushed on disk in async mode, how to check the disk space?). Besides, as it impaces each write operation, we need to focus on write operstions which's batchsize=1. This discuss is not for getting "+1" or "-1" (though anyone can reply the vote..). I just want to discuss that do we REALLY consider and analyze the feature and the implementation carefully? If not, then this big feature is not the time to be merged (and I will call a vote then), and then let's rethink it and make it really available together. If yes, we also need to rethink it and improve it for better performance. Best, ----------------------------------- Xiangdong Huang School of Software, Tsinghua University Chao Wang <[email protected]> 于2023年4月10日周一 19:14写道： Agree with Houliang's opinion. Thanks! Chao Wang BONC ltd On 4/10/2023 19:01，Houliang Qi<[email protected]> wrote： -1 First of all, thanks Xiangdong for pointing out IoTDB's Charter. "RESOLVED, that the Apache IoTDB Project be and hereby is responsible for the creation and maintenance of software related to an IoT native database with high performance for data management and analysis, on the edge and the cloud." As the charter post, IoTDB can be deployed in the cloud, this is why we deploy the multi-tenancy feature. The cloud can be a public or private cloud if we can deploy only one IoTDB cluster, and manage multi databases and users with different resources, which will simplify the maintenance. -> 1) how many side-effects the feature will bring; We have done some tests under[1], which says with 20 databases and 1 user when we set `quota_enable` to true to enable the multi-tenancy feature, the write performance is only slowed down 1.75%, the read latency has not much difference, we will do more tests to show the side-effects in the feature. -> 2) how to reduce the effect when IoTDB is deployed on the edge. We supply one switch about this feature, called `quota_enable`, by default this value is false, so it has no effect when IoTDB is deployed on the edge. This also answers Jinrui's doubt. -> 3) some checks failed on WinOS, are they irrelevant? No, I think they are not irrelevant, the false check message is about the Compaction module, and I see the former pr[2][3] which have been merged 4 days ago has the same issue, so I suspect that the compaction module has occasional bugs -> 4) The feature SHOULD be discussed carefully in the community, rather that submit PRs and merged after some reviews. Besides the above, when we merge this pr, we posted the design in the feishu[4] and discussed it online as least two times, and emailed and discussed it with everyone[5], it has been passed 10 days. The IoTDB community is open and different opinions are welcome. After all, we all have the same original intention of wanting IoTDB's features to be more diverse. [1] https://apache-iotdb.feishu.cn/docx/DbqCd8t3EoxlCFx1yYicd9N4n4s [2] https://github.com/apache/iotdb/actions/runs/4625220921/jobs/8181102446 [3] https://github.com/apache/iotdb/actions/runs/4531046594/jobs/7980725316 [4] https://apache-iotdb.feishu.cn/docx/doxcnKOYKDmJ40FpVnVsPMd3nTg [5] https://lists.apache.org/thread/y6dqcm2o7qk0nbkllb61bp8cv6d3m1h7 Thanks, --------------------------------------- Houliang Qi BONC, Ltd ---- Replied Message ---- | From | 张金瑞<[email protected]> | | Date | 04/10/2023 15:03 | | To | dev<[email protected]> | | Subject | Re：[discuss] consider revert the feature of multi-tenancy | +1, Agree with Xiangdong's opinion. And on the other hand, checking this PR's side effects may take lot of time and during this period, there may be lots of users using latest code to deploy/upgrade their systems. So the best practice is reverting this PR until the side-effect is eliminated Thanks, Zhang Jinrui，Apache IoTDB PMC Original From:"Xiangdong Huang"< [email protected] >; Date:2023/4/10 10:05 To:"dev"< [email protected] >; Subject:[discuss] consider revert the feature of multi-tenancy Hi all, I see the multi-tenancy feature is merged, and several committers made a lot of contributions on that. As multi-tenancy is quite a big feature, which may change IoTDB's position. The feature SHOULD be discussed carefully in the community, rather that submit PRs and merged after some reviews. Therefore, I call to revert the PR and discuss ASAP about the feature after that. At least, the proposer need to answer the following questions, 1) how many side-effect the feature will bring; 2) how to reduce the effect when IoTDB is deployed on the edge. 3) some checks failed on WinOS, are they irrelevant? I don't mean of rejecting any big contribution to IoTDB or harming the community's diversity, but accepting this feature is really big decision and it deserves us to take time to deliberate. Attached IoTDB's Charter: "RESOLVED, that the Apache IoTDB Project be and hereby is responsible for the creation and maintenance of software related to an IoT native database with high performance for data management and analysis, on the edge and the cloud." [1] https://github.com/apache/iotdb/pull/9534/checks Best, ----------------------------------- Xiangdong Huang School of Software, Tsinghua University
