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Date: Mon, 28 Jul 2014 18:16:57 +0800
Message-ID: 
 <CAMZUsP7cjHS43HB3ZrQWYGubcdSO9JTSxuNg5q3ZzmNK0=hnhw@mail.gmail.com>
Subject: Re: delete a row in hbase:meta
From: Qiang Tian <tianq01@gmail.com>
To: "user@hbase.apache.org" <user@hbase.apache.org>
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unfortunately the log was deleted and cannot be reproduced...only have
below data in meta table just before the problem happened :

 moma,,1406539662740.c0a589ce74c8bad980d16947fdf56 column=info:regioninfo,
timestamp=1406541888175, value={ENCODED =>
c0a589ce74c8bad980d16947fdf56036, NAME =>
'moma,,1406539662740.c0a589ce74c8bad9
 036.                                              80d16947fdf56036.',
STARTKEY => '', ENDKEY => ''}
 moma,,1406539662740.c0a589ce74c8bad980d16947fdf56
column=info:seqnumDuringOpen, timestamp=1406541888222,
value=\x00\x00\x00\x00\x00\x00\x00*\x01*
 036.
 moma,,1406539662740.c0a589ce74c8bad980d16947fdf56 column=info:server,
timestamp=1406541888222, value=HRegionServer3:60020
 036.
 moma,,1406539662740.c0a589ce74c8bad980d16947fdf56
column=info:serverstartcode, timestamp=1406541888222, value=1406312768813
 036.
 moma,\x00"\x00\x00\x00\x012+\xF8\xCB\xF0,14064686
column=info:seqnumDuringOpen, timestamp=1406478771359,
value=\x00\x00\x00\x00\x00\x00\x00*\x01*
 25503.6936ebd2ae1d85fc09f243a767229339.
 moma,\x00"\x00\x00\x00\x012+\xF8\xCB\xF0,14064686 column=info:server,
timestamp=1406478771359, value=HRegionServer2:60020
 25503.6936ebd2ae1d85fc09f243a767229339.
 moma,\x00"\x00\x00\x00\x012+\xF8\xCB\xF0,14064686
column=info:serverstartcode, timestamp=1406478771359, value=1406312832708
 25503.6936ebd2ae1d85fc09f243a767229339.

there are 2 rowkeys:
 moma,,1406539662740.c0a589ce74c8bad980d16947fdf56036.
 moma,\x00"\x00\x00\x00\x012+\xF8\xCB\xF0,1406468625503.6936ebd2ae1d85fc09f243a767229339.

the first was deleted via drop 'moma' command, the second cannot.
it looks during delete table, we look up "info:regioninfo" in meta to
locate the related regions, since the second has no "info:regioninfo"
column, it is ignored by hbase?

further investigation shows the 2 regions are just after
split(info:seqnumDuringOpen=1), but it looks updating meta during split
should have updated those info...

thanks.


On Mon, Jul 28, 2014 at 1:28 PM, Ted Yu <yuzhihong@gmail.com> wrote:

> Using hbck is recommended for such scenario.
>
> Did you look at master / region server logs to see if there is some clue
> during table drop operation ?
>
> Cheers
>
> On Jul 27, 2014, at 10:00 PM, Qiang Tian <tianq01@gmail.com> wrote:
>
> > Thanks Ted,
> > An user on 0.96 deletes a table region on HDFS by mistake, so he wants to
> > delete the entire table and recreate it. after disable&drop, he finds the
> > table's region info still exists in meta table..
> >
> > from the code, we should be able to delete the related info during table
> > drop, I suspect the startRow(<tablename>,,) in getTableStartRowForMeta
> > might not be correct?
> >
> > ps could hbck tool could fix it? (he deleted it finally via java code,
> will
> > see if we could repro it...)
> >
> >
> >
> > On Mon, Jul 28, 2014 at 12:05 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> >
> >> Deleting from hbase:meta is for advanced users :-)
> >>
> >> Can you tell us why that row needs to be deleted ?
> >>
> >> Cheers
> >>
> >>
> >> On Sun, Jul 27, 2014 at 8:32 PM, Qiang Tian <tianq01@gmail.com> wrote:
> >>
> >>> Hi Guys,
> >>>
> >>> for a row in hbase:meta like below, how to delete it? due to the chars
> of
> >>> startkey,  it cannot be found.
> >>> delete
> >>
> 'hbase:meta','moma,\x00"\x00\x00\x00\x012+\xF8\xCB\xF0,1406468625503.6936ebd2ae1d85fc09f243a767229339.','info:seqnumDuringOpen'
> >>>
> >>> ERROR: Row Not Found
> >>>
> >>> thanks!
> >>
>

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