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HBase, mail # dev - Re: How to replace MetaUtils.ScannerListener?


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Re: How to replace MetaUtils.ScannerListener?
Jean-Marc Spaggiari 2013-03-23, 12:26
My initial question was about MetaUtils.ScannerListener but I can see
that it went over that ;)

Since no-one is against keeping off line merges for now, I will apply
my modifications into it directly. I will not put ScannerListerner
back to MetaUtils since Merge seems to be the only class to use it.

JMS

2013/3/22 Nick Dimiduk <[EMAIL PROTECTED]>:
> Err, "an *empty* source file".
>
> On Fri, Mar 22, 2013 at 4:33 PM, Nick Dimiduk <[EMAIL PROTECTED]> wrote:
>
>> On Fri, Mar 22, 2013 at 8:19 AM, Jonathan Hsieh <[EMAIL PROTECTED]> wrote:
>>
>>> Let me offer a counter argument.  The offline splitting code is still
>>> present even though online splitting isn't the problem it used to be. We
>>> actually added an extenal wal replayer even though we have wal replay in
>>> our normal recovery path.  Copy table still exists even though snapshots
>>> and snapshot export exists.  Would we consider removing these?
>>>
>>
>> Somewhat tangential to this thread, I think we shouldn't be shy about
>> deleting old/stale/deprecated code. This should be done on a case-by-case
>> basis, of course. For example, in this case, maybe the snapshot
>> functionality will evolve such that the CopyTable interface and semantics
>> become a pure subset of snapshots. At that point, we should absolutely
>> delete CopyTable as an independent code-path.
>>
>> As they say, "an source file ships no bugs".
>>
>> Just my 2¢
>> -n
>>
>>  On Thu, Mar 21, 2013 at 7:07 PM, Jean-Marc Spaggiari <
>>> [EMAIL PROTECTED]> wrote:
>>>
>>> > Hi Enis,
>>> >
>>> > I totaly agree. But even if online merge are available, maybe offline
>>> > merges can still usefull in case the cluster is down for maintenance,
>>> > or because there is any issue to start it, or anything else? We have
>>> > it, so we should maybe try to keep it?
>>> >
>>> > JM
>>> >
>>> > 2013/3/21 Enis Söztutar <[EMAIL PROTECTED]>:
>>> > > Thanks J-M.
>>> > >
>>> > > What I am trying to understand is that whether we should cut the cord
>>> for
>>> > > offline merge once online is working. If you think about it, there
>>> should
>>> > > not be a need to merge offline tables.
>>> > >
>>> > > Enis
>>> > >
>>> > >
>>> > > On Thu, Mar 21, 2013 at 3:16 PM, Jean-Marc Spaggiari <
>>> > > [EMAIL PROTECTED]> wrote:
>>> > >
>>> > >> Offline merge is already there and working fine.
>>> > >>
>>> > >> The usecase here was to retreive all the regions for a given table to
>>> > >> merge them 2 by 2, offline.
>>> > >>
>>> > >> It's working fine, but since the Meta rework it's not working anymore
>>> > >> and I'm trying to rebase the patch.
>>> > >>
>>> > >> Like J-D is saying, yes, it's used only in the offline merge... And
>>> > >> since the online merge is coming, I think it's cleaner to keep the
>>> > >> code in the offline merge since it will disapear soon, but in the
>>> > >> meantime, at least, we will have the offline one.
>>> > >>
>>> > >> JM
>>> > >>
>>> > >> 2013/3/21 Enis Söztutar <[EMAIL PROTECTED]>:
>>> > >> > What is the use case behind offline merge? Is it because we cannot
>>> do
>>> > >> > online merge yet? If we can get HBASE-7403 in, is there still need
>>> to
>>> > >> > support offline merge?
>>> > >> >
>>> > >> > Enis
>>> > >> >
>>> > >> >
>>> > >> > On Thu, Mar 21, 2013 at 2:56 PM, Jean-Daniel Cryans <
>>> > [EMAIL PROTECTED]
>>> > >> >wrote:
>>> > >> >
>>> > >> >> As far as I can tell, only the merge code uses MetaUtils to do
>>> > offline
>>> > >> >> work. If this is the code you are in then pull it back into
>>> MetaUtils
>>> > >> >> I think.
>>> > >> >>
>>> > >> >> J-D
>>> > >> >>
>>> > >> >> On Thu, Mar 21, 2013 at 2:44 PM, Jean-Marc Spaggiari
>>> > >> >> <[EMAIL PROTECTED]> wrote:
>>> > >> >> > Vector is because of a very old bad habit ;) I will change that
>>> to
>>> > >> >> ArrayList.
>>> > >> >> >
>>> > >> >> > So far I have inlined the scanMetaRegion feature into the Merge,
>>> > but
>>> > >> >> > maybe it should be cleaner to put it back in?
>>> > >> >> >
>>> > >> >> > Anyway, I will keep the inlined one until everything is cleaned.