https://issues.apache.org/jira/browse/HBASE-21745

张铎(Duo Zhang) <palomino...@gmail.com> 于2019年1月19日周六 上午9:51写道:

> OK, the original issue is HBCK2 for AMv2, but here we need to do more, not
> only for AMv2.
>
> Let me open a new issue and post what Andrew said above there.
>
> 张铎(Duo Zhang) <palomino...@gmail.com> 于2019年1月19日周六 上午9:26写道:
>
>> OK, let me find the original HBCK2 issue and see how can we make progress
>> on it.
>>
>> BTW, on scan performance, Zheng Hu has done a work to get about 40%
>> performance back in this issue for 100% scan case on ycsb
>>
>> https://issues.apache.org/jira/browse/HBASE-21657
>>
>> Andrew Purtell <apurt...@apache.org> 于2019年1月19日周六 上午8:14写道:
>>
>>> Lars was testing tip of branch-2 with Phoenix and said scans were 50%
>>> slower than branch-1. I’ll try and get him to provide more details.
>>> Anyway
>>> after hbck2 is complete issues like that will come out in the testing
>>> we’d
>>> do as part of sanity checking a move of the pointer.
>>>
>>> On Fri, Jan 18, 2019 at 4:02 PM Zach York <zyork.contribut...@gmail.com>
>>> wrote:
>>>
>>> > I agree with the sentiment around HBCK2. I think these kind of recovery
>>> > tools are essential before marking something stable.
>>> >
>>> > I also remember when we did testing around HBase 2.x/2.1 that we were
>>> > getting perf degradations and couldn't seem to get performance to be as
>>> > good as we were getting in the 1.x line.
>>> >
>>> > - Zach
>>> >
>>> > On Thu, Jan 17, 2019 at 11:06 PM Pankaj kr <pankaj...@huawei.com>
>>> wrote:
>>> >
>>> > > Yeah, HBCK2/ OfflineMetaRepair tools are really required to migrate
>>> old
>>> > > version data to HBase-2. We have use cases where we are using these
>>> tools
>>> > > to rebuild the meta for further region assignment.
>>> > > Similar discussion is going on HBASE-21665, after fixing the NPE and
>>> > > rebuilding the meta, master don't assign the regions as we skip the
>>> empty
>>> > > regions while loading meta during master startup.
>>> > >
>>> > > A big +1 from my side on this...
>>> > >
>>> > > Regards,
>>> > > Pankaj
>>> > >
>>> > > -----Original Message-----
>>> > > From: 张铎(Duo Zhang) [mailto:palomino...@gmail.com]
>>> > > Sent: 18 January 2019 11:55
>>> > > To: HBase Dev List <dev@hbase.apache.org>
>>> > > Subject: Re: [DISCUSS] Moving towards a branch-2 line that can get
>>> the
>>> > > 'stable' pointer.
>>> > >
>>> > > So the first priority is to make progress on HBCK2? If we all agree,
>>> > let's
>>> > > start to work.
>>> > >
>>> > > Andrew Purtell <apurt...@apache.org> 于2019年1月18日周五 下午12:31写道:
>>> > >
>>> > > > Sorry, let me add... Check all the boxes on that list and I'm +1
>>> for
>>> > > > moving the stable pointer (modulo some time to pound on the
>>> candidate
>>> > > > to really put it through its paces, like two weeks of chaos...)
>>> > > >
>>> > > > On Thu, Jan 17, 2019 at 8:28 PM Andrew Purtell <
>>> apurt...@apache.org>
>>> > > > wrote:
>>> > > >
>>> > > > > I do not believe we should move the stable pointer to any 2.x
>>> until
>>> > > > > HBCK2 is feature complete. We can discuss what that milestone
>>> should
>>> > > look like.
>>> > > > > At a minimum, I think we need:
>>> > > > >
>>> > > > >    - Rebuild meta from region metadata in the filesystem, aka
>>> offline
>>> > > > >    meta rebuild.
>>> > > > >    - Fix assignment errors (undeployed regions, double
>>> assignments
>>> > > (yes,
>>> > > > >    should not be possible), etc)
>>> > > > >    - Fix region holes, overlaps, and other errors in the region
>>> chain
>>> > > > >    - Fix failed split and merge transactions that have failed to
>>> roll
>>> > > > >    back due to some bug (related to previous)
>>> > > > >    - Enumerate store files to determine file level corruption and
>>> > > > >    sideline corrupt files
>>> > > > >    - Fix hfile link problems (dangling / broken)
>>> > > > >
>>> > > > > This is a list of the real problems I have had to fix in
>>> production
>>> > > > > at least once (in the past 10 years...).
>>> > > > >
>>> > > > > On Thu, Jan 17, 2019 at 8:19 PM 张铎(Duo Zhang)
>>> > > > > <palomino...@gmail.com>
>>> > > > > wrote:
>>> > > > >
>>> > > > >> There are still lots of small new features which we want to
>>> > > > >> integrate
>>> > > > into
>>> > > > >> branch-2 so I'm -1 on making release directly from branch-2.
>>> > > > >> Backporting at once before release is a pain I'd say, I've tried
>>> > > > >> this many times recently, as we have to follow up the community
>>> > > > >> version...Let's make a branch-2.2 when we want to release 2.2.0,
>>> > > > >> and maybe also retire the branch-2.0?
>>> > > > >>
>>> > > > >> For the stable pointer, I think 2.1.x maybe a good candidate?
>>> > > > >> Though we know that we may still have some bugs for the AMv2,
>>> but
>>> > > > >> actually we all know that the AMv1 for all the branch-1.x also
>>> has
>>> > > > >> lots of bugs, that's why hbck is very important.
>>> > > > >>
>>> > > > >> And also +! on making progress on HBCK2, we need to port he
>>> useful
>>> > > > >> features of HBCK1 to HBCK2. There is no software can guarantee
>>> that
>>> > > > >> there is no bug, so FWIW we should have a way to fix broken
>>> > > > >> clusters.
>>> > > > >>
>>> > > > >> Sean Busbey <bus...@apache.org> 于2019年1月18日周五 上午11:47写道:
>>> > > > >>
>>> > > > >> > There are a few related topics I'd like to discuss and I
>>> figured
>>> > > > >> > this subject line is the most likely to get a bit of
>>> attention.
>>> > > > >> > :)
>>> > > > >> >
>>> > > > >> > First, I'd like us all to get on the same page wrt the current
>>> > > > >> > state of branch-2. Personally, I don't think it can be
>>> released
>>> > > > >> > as-is with a 2.y version because folks can't rolling upgrade
>>> from
>>> > > > >> > 2.0 or 2.1 to it due to the current implementation of
>>> > > > >> > HBASE-20881. As Duo has mentioned a couple of times, folks
>>> have
>>> > > > >> > to ensure there are no region transitions around during the
>>> > > > >> > upgrade. I think that will be prohibitive for folks looking to
>>> > > upgrade. What do other folks think?
>>> > > > >> >
>>> > > > >> > Second, I think our recent discussions around the need for
>>> > > > >> > shifting to more minor releases for HBase 1.y also applies to
>>> the
>>> > > 2.y branches.
>>> > > > >> > branch-2 hasn't had a release since 2.1.0 came out in July
>>> 2018.
>>> > > > >> > That's a scary long amount of time. I think it contributes to
>>> us
>>> > > > >> > ending up with changes like the above since it's easy to think
>>> > > > >> > about the branch as something that has a lot of time before
>>> the
>>> > > > >> > next release.
>>> > > > >> >
>>> > > > >> > Personally, I'd like to see us skip making minor-release
>>> specific
>>> > > > >> > branches for a bit unless a CVE fix or something comes up.
>>> > > > >> > Ideally, that would mean we work towards a 2.2.0 release
>>> directly
>>> > > > >> > from branch-2 and then 2.2.1, etc. When we have a feature
>>> that's
>>> > > > >> > ready to backport from the master branch for a release we then
>>> > > > >> > update branch-2's version to be 2.3.0.
>>> > > > >> >
>>> > > > >> > Or maybe we try set a regular cadence to feature releases by
>>> > > > >> > having
>>> > > > >> > branch-2 release a new minor, two months of new maintenance
>>> > > > >> > releases, followed by a new minor. That would mean after the
>>> last
>>> > > > >> > of the maintenance releases we'd have a window of a few weeks
>>> > > > >> > where we can all decide which features in master are mature
>>> > > > >> > enough to backport for the new minor release.
>>> > > > >> >
>>> > > > >> > Lastly, what would it take for folks to feel confident moving
>>> the
>>> > > > >> > 'stable' pointer to a HBase 2.y? Is there a major gap still on
>>> > > > >> > assignment stability? Is it a more thorough look at
>>> performance?
>>> > > > >> > More time to ensure HBCK2 has good coverage of failure modes
>>> that
>>> > > need it?
>>> > > > >> >
>>> > > > >>
>>> > > > >
>>> > > > >
>>> > > > > --
>>> > > > > Best regards,
>>> > > > > Andrew
>>> > > > >
>>> > > > > Words like orphans lost among the crosstalk, meaning torn from
>>> > > > > truth's decrepit hands
>>> > > > >    - A23, Crosstalk
>>> > > > >
>>> > > >
>>> > > >
>>> > > > --
>>> > > > Best regards,
>>> > > > Andrew
>>> > > >
>>> > > > Words like orphans lost among the crosstalk, meaning torn from
>>> truth's
>>> > > > decrepit hands
>>> > > >    - A23, Crosstalk
>>> > > >
>>> > >
>>> >
>>> --
>>> Best regards,
>>> Andrew
>>>
>>> Words like orphans lost among the crosstalk, meaning torn from truth's
>>> decrepit hands
>>>    - A23, Crosstalk
>>>
>>

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