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Date: Tue, 29 Oct 2013 08:24:51 -0600
From: Keith Freeman <8forty@gmail.com>
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To: user@cassandra.apache.org
Subject: Re: CQL & selecting individual items from a map
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 <CAK2p28NqjPq6S=Y6syVhiq6sd=cUV+14WZ4BSGFF9Py+huHMfQ@mail.gmail.com>
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There's some rationale here: 
http://mail-archives.apache.org/mod_mbox/cassandra-user/201305.mbox/%3CCAENxBwx6pcSA=cWn=dKW_52K5odw5F3Xigj-zn_4BwFth+4ruA@mail.gmail.com%3E

And I'm sure part of the reason is the 64k size limit: maps (and sets 
and lists) are limited to 64k total size 
(http://wiki.apache.org/cassandra/CassandraLimitations), so it wouldn't 
be very read-efficient to load individual elements.

On 10/28/2013 08:03 PM, Liam Stewart wrote:
> I was wondering if anybody could explain the rationale behind 
> disallowing selection of individual elements from a map in CQL and why 
> an entire map must be retrieved at once when items are stored as 
> distinct columns? Are there any plans to allow individual selection?
>
> -- 
> Liam Stewart :: liam.stewart@gmail.com <mailto:liam.stewart@gmail.com>


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    There's some rationale here:
    <meta http-equiv="content-type" content="text/html;
      charset=ISO-8859-1">
    <a
href="http://mail-archives.apache.org/mod_mbox/cassandra-user/201305.mbox/%3CCAENxBwx6pcSA=cWn=dKW_52K5odw5F3Xigj-zn_4BwFth+4ruA@mail.gmail.com%3E">http://mail-archives.apache.org/mod_mbox/cassandra-user/201305.mbox/%3CCAENxBwx6pcSA=cWn=dKW_52K5odw5F3Xigj-zn_4BwFth+4ruA@mail.gmail.com%3E</a><br>
    <br>
    And I'm sure part of the reason is the 64k size limit: maps (and
    sets and lists) are limited to 64k total size (<a
      href="http://wiki.apache.org/cassandra/CassandraLimitations">http://wiki.apache.org/cassandra/CassandraLimitations</a>),
    so it wouldn't be very read-efficient to load individual elements.<br>
    <br>
    <div class="moz-cite-prefix">On 10/28/2013 08:03 PM, Liam Stewart
      wrote:<br>
    </div>
    <blockquote
cite="mid:CAK2p28NqjPq6S=Y6syVhiq6sd=cUV+14WZ4BSGFF9Py+huHMfQ@mail.gmail.com"
      type="cite">
      <div dir="ltr">I was wondering if anybody could explain the
        rationale behind disallowing selection of individual elements
        from a map in CQL and why an entire map must be retrieved at
        once when items are stored as distinct columns? Are there any
        plans to allow individual selection?
        <div>
          <br>
        </div>
        <div>-- <br>
          Liam Stewart :: <a moz-do-not-send="true"
            href="mailto:liam.stewart@gmail.com">liam.stewart@gmail.com</a>
        </div>
      </div>
    </blockquote>
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