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From Billie Rinaldi <>
Subject Re: scan command hung
Date Mon, 05 Oct 2015 16:13:49 GMT
Yes.  In this case, I would suggest configuring the column families that
have very few rows to be in a separate locality group.  You should be able
to do this in the shell with the command:
setgroups groupname=colf1,colf2,colf3 -t tablename

Here, groupname is an arbitrary name for the group; colf1, colf2, and colf3
are the column families with few rows; and tablename is the table name.
After you create the locality group, you will need to compact the table for
the change to take effect:
compact -t tablename -w

For each table, you can create multiple locality groups tailored to the
access patterns of your data.  There is some additional information about
locality groups in the user manual:

On Mon, Oct 5, 2015 at 8:25 AM, z11373 <> wrote:

> Hi Josh,
> I see there are 4 tablet files for that table, and all of them are in range
> from 730MB to 860MB in size.
> For those column families that have problem, they are in 2 of those 4
> tablets.
> They are only a few rows, but for those column families which have no
> problem, they have millions of rows.
> This makes me thinking if the slowness because it has to find those 'few'
> rows among those 'gigantic' rows in that physical tablet file?
> Thanks,
> Z
> --
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> Sent from the Developers mailing list archive at

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