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From: eugene miretsky <eugene.miretsky@gmail.com>
Date: Wed, 15 Nov 2017 11:12:50 -0500
Message-ID: <CAK4TV3i7HmHuBMBTEhbveirqTn-6i4ZuxEmKrjLwHucgf9iP5w@mail.gmail.com>
Subject: CQL Map vs clustering keys
To: user@cassandra.apache.org
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archived-at: Wed, 15 Nov 2017 16:12:56 -0000

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Hi,

What would be the tradeoffs between using

1) Map

(

id UUID PRIMARY KEY,

myMap map<int,text>

);

2) Clustering key

(

 id UUID PRIMARY KEY,

key int,

val text,

PRIMARY KEY (id, key))

);

My understanding is that maps are stored very similarly to clustering
columns, where the map key is part of the SSTable's column name. The main
difference seems to be that with maps all the key/value pairs get retrieved
together, while with clustering keys we can retrieve individual rows, or a
range of keys.

Cheers,
Eugene

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<div dir=3D"ltr">Hi,=C2=A0<div><br></div><div>What would be the tradeoffs b=
etween using</div><br>1) Map<br><br>(<blockquote style=3D"margin:0 0 0 40px=
;border:none;padding:0px"><div>id UUID PRIMARY KEY,=C2=A0=C2=A0</div></bloc=
kquote><blockquote style=3D"margin:0 0 0 40px;border:none;padding:0px"><div=
><div>myMap map&lt;int,text&gt;</div></div></blockquote><div><div>);<br><br=
>2) Clustering key</div><div><br>(</div></div><blockquote style=3D"margin:0=
 0 0 40px;border:none;padding:0px"><div><div>=C2=A0id UUID PRIMARY KEY,</di=
v></div></blockquote><blockquote style=3D"margin:0 0 0 40px;border:none;pad=
ding:0px"><div><div>key int,</div></div></blockquote><blockquote style=3D"m=
argin:0 0 0 40px;border:none;padding:0px"><div><div>val text,</div></div></=
blockquote><blockquote style=3D"margin:0 0 0 40px;border:none;padding:0px">=
<div><div>PRIMARY KEY (id, key))</div></div></blockquote><div><div>);</div>=
</div><div><br></div><div>My understanding is that maps are stored very sim=
ilarly to clustering columns, where the map key is part of the SSTable&#39;=
s column name. The main difference seems to be that with maps all the key/v=
alue pairs get retrieved together, while with clustering keys we can retrie=
ve individual rows, or a range of keys.=C2=A0</div><div><br></div><div>Chee=
rs,</div><div>Eugene=C2=A0</div></div>

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