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From Scott Shealy <spshe...@yahoo.com>
Subject Re: Worst case #iops to read a row
Date Sat, 10 Apr 2010 13:00:50 GMT
thanks , that is helpful

S.

----- Original Message ----
From: Jonathan Ellis <jbellis@gmail.com>
To: user@cassandra.apache.org
Sent: Fri, April 9, 2010 11:39:26 AM
Subject: Re: Worst case #iops to read a row

worst case is 2 or 3, depending on row size:

one seek to read the right row index block
one seek to read the row header (bloom filter + column index)
if it's a big row, one seek to read the column block (block size is
configurable, default is 256KB)

On Thu, Apr 8, 2010 at 5:21 PM, Scott Shealy <spshealy@yahoo.com> wrote:
> Not knowing know anything  about the physical layout of the data on disk or how it is
accessed when it is read... Could someone who does help
> estimate the worst case scenario(no caching at any level) for the number of iops to read
a row of modest size and modest number of columns in a
> large column family.
>
> TIA,
>
> S.
>
>


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