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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 ?
Hi,
I have tested read performance after reducing number of column families
from 14 to 3 and yes there is improvement.
Meanwhile i was going through the paper published by google on BigTable.
It says

"It is our intent that the number of distinct column
families in a table be small (in the hundreds at most), and
that families rarely change during operation."

So Is that theoretical value ( 100 CFs )  or its possible but not with the
current version of Hbase ?
On Tue, Jul 2, 2013 at 12:48 AM, Viral Bajaria <[EMAIL PROTECTED]>wrote:

> On Mon, Jul 1, 2013 at 10:06 AM, Vimal Jain <[EMAIL PROTECTED]> wrote:
>
> > 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.
> >
>
> This answers the type of data in each cell not the size of data. Can you
> figure out the average size of data that you insert in that size. For
> example what is the length of the byte array ? Also for java primitive, is
> it 8-byte long ? 4-byte int ?
> In addition to that, what is in the row key ? How long is that in bytes ?
> Same for column family, can you share the names of the column family ? How
> about qualifiers ?
>
> If you have disabled major compactions, you should run it once a few days
> (if not once a day) to consolidate the # of files that each scan will have
> to open.
>
> 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.
> >
>
> How many disks do you have in your box ? Have you ever benchmarked the
> hardware ?
>
> Thanks,
> Viral
>

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Thanks and Regards,
Vimal Jain