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From Frédéric Fondement <frederic.fondem...@uha.fr>
Subject Change compressor on existing tables
Date Mon, 11 Jul 2011 09:04:46 GMT
Another related question: is there a mean to change compressor (or 
enable compressor) on an existing column family without breaking 
existing data (e.g. from LZO to snappy) ?

Le 10/07/11 10:21, Weiwei Xiong a écrit :
> Now I applied the major_compact on a table with BLOOMFILTER enabled. But how
> can I make sure if the row-keys have really been added into the bloomfilter?
>
>
> I profiled the cost of<HTable>.exists(<Get>) but it seems to me BF didn't
> give me speedup comparing with the execution without BLOOMFILTER enabled.
>
> Am I missing anything here?
>
> Thanks
> ww
>
> On Sat, Jul 9, 2011 at 1:32 PM, Weiwei Xiong<xiongww@gmail.com>  wrote:
>
>> Thanks Andrew. I will give it a try.
>>
>> ww
>>
>>
>> On Fri, Jul 8, 2011 at 6:45 PM, Andrew Purtell<apurtell@apache.org>wrote:
>>
>>> Sorry that is:
>>>
>>>    major_compact 'tablename'
>>>
>>> Typing too fast...
>>>
>>> Best regards,
>>>
>>>
>>>     - Andy
>>>
>>> Problems worthy of attack prove their worth by hitting back. - Piet Hein
>>> (via Tom White)
>>>
>>>
>>> ----- Original Message -----
>>>> From: Andrew Purtell<apurtell@apache.org>
>>>> To: "user@hbase.apache.org"<user@hbase.apache.org>
>>>> Cc:
>>>> Sent: Friday, July 8, 2011 6:42 PM
>>>> Subject: Re: Enable BLOOMFILTER on existing tables
>>>>
>>>> You can update existing data through manually triggering compaction.
>>> After you
>>>> make a change like this, go to the hbase shell and execute:
>>>>
>>>>    major_compaction 'yourtablename'
>>>>
>>>> After major compaction all of the store files for the table will abide
>>> the most
>>>> recent schema settings.
>>>>
>>>> Best regards,
>>>>
>>>>
>>>>     - Andy
>>>>
>>>>
>>>> Problems worthy of attack prove their worth by hitting back. - Piet Hein
>>> (via
>>>> Tom White)
>>>>
>>>>
>>>> ----- Original Message -----
>>>>>   From: Weiwei Xiong<xiongww@gmail.com>
>>>>>   To: user@hbase.apache.org
>>>>>   Cc:
>>>>>   Sent: Friday, July 8, 2011 6:02 PM
>>>>>   Subject: Enable BLOOMFILTER on existing tables
>>>>>
>>>>>   Hi all,
>>>>>
>>>>>   I want to enable the bloomfilter on some existing tables to speed-up
>>>> row-key
>>>>>   existence checking.  I altered the BLOOMFILTER from "NONE" to
>>>>>   "ROW" for this
>>>>>   purpose.
>>>>>
>>>>>   But one think I am not clear is, will the setting change also take
>>> effect
>>>> on
>>>>>   pre-existing rows? Or only rows to be inserted in future get the
>>>> BLOOMFILTER
>>>>>   property?
>>>>>
>>>>>   If bloomfilter change won't be applied to existing rows, is there any
>>>> other
>>>>>   way to speed up the row-key existence checking?
>>>>>
>>>>>   Thanks,
>>>>>   ww
>>>>>
>>


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