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HBase, mail # user - How many column families in one table ?


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Re: How many column families in one table ?
Vimal Jain 2013-07-01, 17:06
Sorry for the typo .. please ignore previous mail.. Here is the corrected
one..
1)I have around 140 columns for each row , out of 140 , around 100 columns
hold java primitive data type , remaining 40 columns  contain serialized
java object as byte array(Inside each object is an ArrayList). Yes , I do
delete data but the frequency is very less ( 1 out of 5K operations ). I
dont run any compaction.
2) I had ran scan keeping in mind the CPU,IO and other system related
parameters.I found them to be normal with system load being 0.1-0.3.
3) Yes i have 3 versions of cell ( default value).

On Mon, Jul 1, 2013 at 10:33 PM, Vimal Jain <[EMAIL PROTECTED]> wrote:

> Hi Lars,
> 1)I have around 140 columns for each row , out of 140 , around 100 rows
> are holds java primitive data type , remaining 40 rows contains serialized
> java object as byte array. Yes , I do delete data but the frequency is very
> less ( 1 out of 5K operations ). I dont run any compaction.
> 2) I had ran scan keeping in mind the CPU,IO and other system related
> parameters.I found them to be normal with system load being 0.1-0.3.
> 3) Yes i have 3 versions of cell ( default value).
>
>
> On Mon, Jul 1, 2013 at 9:08 PM, lars hofhansl <[EMAIL PROTECTED]> wrote:
>
>> The performance you're seeing is definitely not typical. 'couple of
>> further questions:
>> - How large are your KVs (columns)?- Do you delete data? Do you run major
>> compactions?
>> - Can you measure: CPU, IO, context switches, etc, during the scanning?
>> - Do you have many versions of the columns?
>>
>>
>> Note that HBase is a key value store, i.e. the storage is sparse. Each
>> column is represented by its own key value pair, and HBase has to do the
>> work to reassemble the data.
>>
>>
>> -- Lars
>>
>>
>>
>> ________________________________
>>  From: Vimal Jain <[EMAIL PROTECTED]>
>> To: [EMAIL PROTECTED]
>> Sent: Monday, July 1, 2013 4:44 AM
>> Subject: Re: How many column families in one table ?
>>
>>
>> Hi,
>> We had some hardware constraints along with the fact that our total data
>> size was in GBs.
>> Thats why to start with Hbase ,  we first began  with pseudo distributed
>> mode and thought if required we would upgrade to fully distributed mode.
>>
>>
>>
>> On Mon, Jul 1, 2013 at 5:09 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
>>
>> > bq. I have configured Hbase in pseudo distributed mode on top of HDFS.
>> >
>> > What was the reason for using pseudo distributed mode in production
>> setup ?
>> >
>> > Cheers
>> >
>> > On Mon, Jul 1, 2013 at 1:44 AM, Vimal Jain <[EMAIL PROTECTED]> wrote:
>> >
>> > > Thanks Dhaval/Michael/Ted/Otis for your replies.
>> > > Actually , i asked this question because i am seeing some performance
>> > > degradation in my production Hbase setup.
>> > > I have configured Hbase in pseudo distributed mode on top of HDFS.
>> > > I have created 17 Column families :( . I am actually using 14 out of
>> > these
>> > > 17 column families.
>> > > Each column family has around on average 8-10 column qualifiers so
>> total
>> > > around 140 columns are there for each row key.
>> > > I have around 1.6 millions rows in the table.
>> > > To completely scan the table for all 140 columns  , it takes around
>> 30-40
>> > > minutes.
>> > > Is it normal or Should i redesign my table schema ( probably merging
>> 4-5
>> > > column families into one , so that at the end i have just 3-4 cf ) ?
>> > >
>> > >
>> > >
>> > > On Sat, Jun 29, 2013 at 12:06 AM, Otis Gospodnetic <
>> > > [EMAIL PROTECTED]> wrote:
>> > >
>> > > > Hm, works for me -
>> > > >
>> > > >
>> > >
>> >
>> http://search-hadoop.com/m/qOx8l15Z1q42/column+families+fb&subj=Re+HBase+Column+Family+Limit+Reasoning
>> > > >
>> > > > Shorter version: http://search-hadoop.com/m/qOx8l15Z1q42
>> > > >
>> > > > Otis
>> > > > --
>> > > > Solr & ElasticSearch Support -- http://sematext.com/
>> > > > Performance Monitoring -- http://sematext.com/spm
>> > > >
>> > > >
>> > > >
>> > > > On Fri, Jun 28, 2013 at 8:40 AM, Vimal Jain <[EMAIL PROTECTED]>

Thanks and Regards,
Vimal Jain