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HBase, mail # dev - [RESULT] ANN: The third hbase-0.96.1 release candidate is available for download


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Re: Re: [RESULT] ANN: The third hbase-0.96.1 release candidate is available for download
Jean-Marc Spaggiari 2013-12-18, 02:51
Thanks for following up Chunhui. That make sense. We will need HBCK to to
aware of that. First easy fix might be just to display a warning. Second
one will be to handle the situation.

So we only have the meta issue remaining now ;)

JM
2013/12/17 Chunhui Shen <[EMAIL PROTECTED]>

> About the online merge:
>
>
> HBCK will report an error now after the online merge,
> because the files of merging regions still remain on HDFS which will be
> cleaned by CatalogJanitor later.
>
>
> In the merge process, we create file references instead of moving files
> together because the latter will break Table Snapshot.
> Thus, we couldn't remove these files until the merged region complete
> compaction.
>
>
> Thanks for the feedback.
>
>
> I will enhance HBCK to handle this case.
>
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> At 2013-12-18 03:21:42,"Jean-Marc Spaggiari" <[EMAIL PROTECTED]>
> wrote:
> >So. Some feedback.
> >
> >0.94.x give "Status: OK" in HBCK.
> >
> >Did a distcp between the 2 clusters, removed splitlog since I'm not able
> to
> >change the owner to my HBase user, did the upgrade, started.
> >
> >I can see all my tables correctly, able to scan them.
> >
> >HBCK reports all the tables as okay, even the hbase:meta table, however,
> >I'm getting this:
> >"ERROR: Empty REGIONINFO_QUALIFIER found in hbase:meta"
> >
> >Ran hbck with -fixEmptyMetaCells
> >Reran it. All clear now.
> >
> >Now, I played with the online merge, and I'm still getting errors but they
> >seems to just be bad timing.
> >
> >tl;tr; jump to the arrow below.
> >
> >There is initially 4 regions in the table. I merge the 2 first one
> >together. That creates a 3 region table. I merge again the 2 first one
> >together. I wait few minutes, and I run HBCK.
> >
> >ERROR: Region { meta => null, hdfs =>
>
> >hdfs://hbasetest1:9000/hbase/data/default/dns/c6569a72cc3c2750d14976ab85f02315,
> >deployed =>  } on HDFS, but not listed in hbase:meta or deployed on any
> >region server
> >ERROR: Region { meta => null, hdfs =>
>
> >hdfs://hbasetest1:9000/hbase/data/default/dns/efa630782e1d603fbc239a11ab292957,
> >deployed =>  } on HDFS, but not listed in hbase:meta or deployed on any
> >region server
> >
> >I merged those 4 regions:
> >merge_region 'bb65f685cdefc4f2491d246f376fc1f0',
> >'d02ce8e3fa1a200c7f034b349acf8cc8'
> >merge_region 'efa630782e1d603fbc239a11ab292957',
> >'c6569a72cc3c2750d14976ab85f02315'
> >
> >And here is the HDFS content after the merge:
> >drwxr-xr-x   - hbase hbase          0 2013-12-17 13:35
> >/hbase/data/default/dns/c6569a72cc3c2750d14976ab85f02315
> >drwxr-xr-x   - hbase hbase          0 2013-12-17 13:35
> >/hbase/data/default/dns/d5b74aaa2853b00b0ad0f20f60c74398
> >drwxr-xr-x   - hbase hbase          0 2013-12-17 13:46
> >/hbase/data/default/dns/efa630782e1d603fbc239a11ab292957
> >drwxr-xr-x   - hbase hbase          0 2013-12-17 13:46
> >/hbase/data/default/dns/f2e0764d4e9dea8bfc0aeed9da3da5f7
> >
> >And the table in the WebUI:
> >dns,,1387305985379.f2e0764d4e9dea8bfc0aeed9da3da5f7.
> >dns,theafronews.ca,1379202071281.d5b74aaa2853b00b0ad0f20f60c74398.
> >
> >Regions efa630782e1d603fbc239a11ab292957 and
> >c6569a72cc3c2750d14976ab85f02315 should not be there anymore.
> >
> >Waiting even longer, they are now removed and hbck reports everything is
> >correct.
> >
> >I know there is some people which are running hbck -repair as a cron job.
> >If that occurs while the regions just got merged, it might re-create the
> >entries in the meta based on the hdfs content and they will have overlaps
> >and duplicates
> >
> >===> So to summarize, seems that merge append pretty quickly, but it waits
> >for the CatalogJanitor to remove the directories left over by the process.
> >I think the merge process should remove those files and not rely on the
> >catalog janitor. I did the test multiple times. First time took about 30
> >seconds for the janitor to clear the paths. But the 2nd time it took 4
> >minutes for the janitor to run and to clear the files...
> >
> >One last small thing. There is no more a split button in the WebUI. When