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From Andrew Purtell <apurt...@apache.org>
Subject Re: Using TTL tout purge data automatically ?
Date Fri, 23 Sep 2011 16:50:18 GMT
This is an occasional source of confusion.

Curious if anyone thinks that TTLs in milliseconds makes sense.

My opinion is no, of what practical use is data with a lifetime of 1, 10, or 100 ms?


----- Original Message -----
> From: Jean-Daniel Cryans <jdcryans@apache.org>
> To: user@hbase.apache.org
> Cc: 
> Sent: Friday, September 23, 2011 9:40 AM
> Subject: Re: Using TTL tout purge data automatically ?
> 
> From the book http://hbase.apache.org/book/ttl.html
> 
> "ColumnFamilies can set a TTL length in seconds"
> 
> and you have:
> 
> TTL => '600000'
> TTL => '300000'
> 
> It's just three orders of magnitude different from what you thought
> you set the TTL to :)
> 
> J-D
> 
> On Fri, Sep 23, 2011 at 2:22 AM, Damien Hardy <dhardy@figarocms.fr> wrote:
>>  Hello,
>> 
>>  I created yesterday an HTable with 2 CF specifying the TTL for 5 an 10 min
>>  respectively.
>> 
>>  Inserted 2 datas (one in each column)
>> 
>>  And hoped that my values desapear passed a certain amount of time.
>> 
>>  This never happend ...
>> 
>>  This morning I keep hope that major_compaction once a days withdraw my
>>  expired datas ...
>> 
>>  Disapointed :
>> 
>>  hbase(main):004:0> describe 'ttltest'
>>  DESCRIPTION
>>                                                       
    ENABLED
>>   {NAME => 'ttltest', FAMILIES => [{NAME => 
> 'longttl', BLOOMFILTER => 'NONE',
>>  REPLICATION_SCOPE => '0', COMPRESSION => 'NONE', 
> VERSION true
>>   S => '1', TTL => '600000', BLOCKSIZE => 
> '65536', IN_MEMORY => 'false',
>>  BLOCKCACHE => 'true'}, {NAME => 'shortttl', 
> BLOOMFILTER => 'N
>>   ONE', REPLICATION_SCOPE => '0', COMPRESSION => 
> 'NONE', VERSIONS => '1', TTL
>>  => '300000', BLOCKSIZE => '65536', IN_MEMORY => 
> 'false',
>>   BLOCKCACHE => 'true'}]}
>> 
>>  hbase(main):005:0> scan 'ttltest'
>>  ROW                                                  COLUMN+CELL
>>   test1                                               column=longttl:data,
>>  timestamp=1316697813182, value=jeudi 22 septembre 2011, 15:22:06 (UTC+0200)
>>   test1                                               column=shortttl:data,
>>  timestamp=1316697803522, value=jeudi 22 septembre 2011, 15:22:06 (UTC+0200)
>>  1 row(s) in 0.1280 seconds
>> 
>> 
>>  Is TTL usable to purge expired values (even the last ones) ?
>> 
>>  Best regards,
>> 
>>  --
>>  Damien
>> 
>

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