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From Ey-Chih chow <eyc...@gmail.com>
Subject Re: terrible! I can't drop the table
Date Mon, 07 May 2012 17:42:48 GMT
If we use the class CleanFromMeta in http://www.mail-archive.com/issues@hbase.apache.org/msg06620.html
to delete related entries in .META., will the corresponding znode for the table get automatically
deleted?  Thanks.

Ey-Chih Chow


On May 7, 2012, at 8:11 AM, Jiajun Chen wrote:

> Yeah !
> delete the znode for that table and restart the cluster then create it
> successfully !
> 
> On 7 May 2012 23:08, Dave Wang <dsw@cloudera.com> wrote:
> 
>> You may need to edit your ZK nodes.  Depending on what version of HBase you
>> are running, you may need to either create or delete the znode for that
>> table.
>> 
>> - Dave
>> 
>> On Mon, May 7, 2012 at 7:57 AM, Jiajun Chen <cjjvictory@gmail.com> wrote:
>> 
>>> I deleted all rows of cjjWaitHash in .META. used deleteall in shell ,and
>>> output nothing after echo "scan '.META.'" | hbase shell | grep
>> cjjWaitHash
>>> .
>>> 
>>> but why ?
>>> 
>>>> count 'cjjWaitHash'
>>> ERROR: Unknown table cjjWaitHash!
>>> 
>>>> enable 'cjjWaitHash'
>>> ERROR: Table cjjWaitHash does not exist.'
>>> 
>>>> disable 'cjjWaitHash'
>>> ERROR: Table cjjWaitHash does not exist.'
>>> 
>>>> create 'cjjWaitHash',{NAME => 'c',COMPRESSION =>'LZO', VERSIONS =>
'1'}
>>> ERROR: Table already exists: cjjWaitHash!
>>> 
>>> 
>>> On 7 May 2012 22:34, Jiajun Chen <cjjvictory@gmail.com> wrote:
>>> 
>>>> But I can't find the key contains cjjWaitHash use the following code:
>>>> 
>>>> public void printMETA() throws IOException
>>>>    {
>>>>        final HTable table = MyHBaseConfiguration.getTable(".META.");
>>>>        final Scan scan = new Scan();
>>>>        final ResultScanner scanner = table.getScanner(scan);
>>>> 
>>>>        while (true)
>>>>        {
>>>>            final Result next = scanner.next();
>>>>            if (null == next)
>>>>            {
>>>> 
>>>>                 return;
>>>>            }
>>>>            final String row = Bytes.toString(next.getRow());
>>>>            if (row.contains("cjjWaitHash"))
>>>>            {
>>>>                System.err.println(row);
>>>>            }
>>>>            System.out.println(row);
>>>> 
>>>>        }
>>>>    }
>>>> 
>>>> On 7 May 2012 22:30, Doug Meil <doug.meil@explorysmedical.com> wrote:
>>>> 
>>>>> 
>>>>> This is why Harsh was suggesting that you look at what is in META for
>>> that
>>>>> table.  Those records have to get cleaned out of META because HBase
>>> thinks
>>>>> that table still exists.
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> On 5/7/12 10:23 AM, "Jiajun Chen" <cjjvictory@gmail.com> wrote:
>>>>> 
>>>>>> I can lost the data , how to create the table with no data ?
>>>>>> 
>>>>>> On 7 May 2012 22:19, Doug Meil <doug.meil@explorysmedical.com>
>> wrote:
>>>>>> 
>>>>>>> 
>>>>>>> Because you did this... "hadoop fs -rmr /hbase/cjjWaitHash"
>>>>>>> 
>>>>>>> ... your data is gone.
>>>>>>> 
>>>>>>> Per...
>>>>>>> 
>>>>>>> http://hbase.apache.org/book.html#trouble.namenode
>>>>>>> 
>>>>>>> 
>>>>>>> ... that's where StoreFiles are kept for that particular table.
>>>>>>> 
>>>>>>> 
>>>>>>> On 5/7/12 10:05 AM, "Jiajun Chen" <cjjvictory@gmail.com>
wrote:
>>>>>>> 
>>>>>>>> which temp directory ?
>>>>>>>> lose the data of all tables ?
>>>>>>>> 
>>>>>>>> On 7 May 2012 22:01, Tom Brown <tombrown52@gmail.com>
wrote:
>>>>>>>> 
>>>>>>>>> I made a very similar mistake myself the other day when
trying
>> to
>>>>>>> reset
>>>>>>>>> my
>>>>>>>>> cluster.  What finally solved it was deleting the temp
directory
>>>>> used
>>>>>>>>> by my
>>>>>>>>> data nodes (in my case I wanted to loose all my data,
so it was
>> ok
>>>>> to
>>>>>>>>> delete everything... In your case, you may have to figure
out
>> how
>>> to
>>>>>>>>> export
>>>>>>>>> some data first, as I don't know exactly what effect
deleting
>> that
>>>>>>> temp
>>>>>>>>> directory will have)
>>>>>>>>> 
>>>>>>>>> Good luck!
>>>>>>>>> 
>>>>>>>>> --Tom
>>>>>>>>> 
>>>>>>>>> On Monday, May 7, 2012, Doug Meil wrote:
>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> Harsh pretty much summed it up already (e.g., "don't
do that")
>>> but
>>>>>>>>> below
>>>>>>>>>> is some further reading of what just happened...
>>>>>>>>>> 
>>>>>>>>>> http://hbase.apache.org/book.html#arch.catalog
>>>>>>>>>> http://hbase.apache.org/book.html#trouble.namenode
>>>>>>>>>> 
>>>>>>>>>> ... META is just an HBase table under the covers.
By deleting
>>> the
>>>>>>>>> table
>>>>>>>>> on
>>>>>>>>>> the HDFS filesystem, it did nothing with the table
metadata in
>>>>>>> META.
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> On 5/7/12 9:18 AM, "Harsh J" <harsh@cloudera.com
>> <javascript:;>>
>>>>>>>>> wrote:
>>>>>>>>>> 
>>>>>>>>>>> The drop is what you ought to have done first,
before
>> removing
>>>>>>> the FS
>>>>>>>>>>> folder and the meta entries. It does all those
actions for
>> you.
>>>>>>> Why
>>>>>>>>>>> did you do it this way?
>>>>>>>>>>> 
>>>>>>>>>>> Do you see the table still appearing in the list
outputs? Can
>>> you
>>>>>>>>>>> provide us a paste bin link of:
>>>>>>>>>>> 
>>>>>>>>>>> echo "scan '.META.'" | hbase shell | grep cjjWaitHash
>>>>>>>>>>> 
>>>>>>>>>>> On Mon, May 7, 2012 at 6:44 PM, Jiajun Chen <
>>>>> cjjvictory@gmail.com
>>>>>>>>> <javascript:;>>
>>>>>>>>>> wrote:
>>>>>>>>>>>> I deleted the folder use bin/hadoop fs -rmr
>>> /hbase/cjjWaitHash
>>>>>>> ,and
>>>>>>>>>>>> deleted
>>>>>>>>>>>> the row with prefix cjjWaitHash in .META.
>>>>>>>>>>>> Now how can I drop the table cjjWaitHash
?
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> 
>>>>>>>>>>> --
>>>>>>>>>>> Harsh J
>>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> --
>>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>> --
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>> 
>> 
> 
> 
> 
> -- 
> 
> 陈加俊  项目经理
> 优讯时代(北京)网络技术有限公司
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> 
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