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Date: Mon, 23 Jul 2012 11:10:44 -0700
Message-ID: 
 <CAOT3TWoO3dM2R82d39cym-V+wNObZH3U-Y1++tnfu9iu33KOog@mail.gmail.com>
Subject: Re: Schema advice: (Single row or multiple row!?) How do I store
 millions of columns when I need to read a set of around 500 columns at a
 single read query using column names ?
From: Mohit Anchlia <mohitanchlia@gmail.com>
To: user@cassandra.apache.org
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On Mon, Jul 23, 2012 at 11:00 AM, Ertio Lew <ertiop93@gmail.com> wrote:

> For each user in my application, I want to store a *value* that is queried
> by using the userId. So there is going to be one column for each user
> (userId as col Name & *value* as col Value). Now I want to store these
> columns such that can efficiently read columns for  atleast  300-500 users
> in a single read query.


Is the query timebased or userid based? How do you determine which users to
read first? Do you read all of them or few of them? What's the query
criteria?

It would be helpful to understand exactly how your query works. In NoSQL
there are no Btree indexes, which means you need to store data that is
materialized based on your query pattern.

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<br><br>
<div class=3D"gmail_quote">On Mon, Jul 23, 2012 at 11:00 AM, Ertio Lew <spa=
n dir=3D"ltr">&lt;<a href=3D"mailto:ertiop93@gmail.com" target=3D"_blank">e=
rtiop93@gmail.com</a>&gt;</span> wrote:<br>
<blockquote style=3D"BORDER-LEFT:#ccc 1px solid;MARGIN:0px 0px 0px 0.8ex;PA=
DDING-LEFT:1ex" class=3D"gmail_quote">For each user in my application, I wa=
nt to store a *value* that is queried by using the userId. So there is goin=
g to be one column for each user (userId as col Name &amp; *value* as col V=
alue). Now I want to store these columns such that can efficiently read col=
umns for=A0 atleast=A0=A0300-500 users in a single read query. </blockquote=
>
</div>
<div>=A0</div>
<div>Is the query timebased or userid based? How do you determine which use=
rs to read first? Do you read all of them or few of them? What&#39;s the qu=
ery criteria?</div>
<div>=A0</div>
<div>It would be helpful to understand exactly how your query works. In NoS=
QL there are no Btree indexes, which means you need to store data that is m=
aterialized based on your query pattern.</div>
<div><br>=A0</div>

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