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Message-ID: <4C80F443.8040106@unitedgames.com>
Date: Fri, 03 Sep 2010 15:12:35 +0200
From: Hugo <hugo@unitedgames.com>
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To: user@cassandra.apache.org
Subject: Re: Consistency issue
References: <4C80D61C.2050302@unitedgames.com>
 <AANLkTikiHi1FvPr=Qb+=LEYF5Te1p=5saPDF1VpvUtAB@mail.gmail.com>
In-Reply-To: <AANLkTikiHi1FvPr=Qb+=LEYF5Te1p=5saPDF1VpvUtAB@mail.gmail.com>
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  I'm using QUORUM, but in my single-node setup this doesn't matter IMHO.

On 9/3/2010 1:51 PM, Nick Telford wrote:
> Which ConsistencyLevels did you use for your batchMutate() and 
> getSlice() operations?
>
> ConsistencyLevels directly dictate the level of consistency you will 
> get with your data.
>
> Regards,
>
> Nick Telford
>
> On 3 September 2010 12:03, Hugo <hugo@unitedgames.com 
> <mailto:hugo@unitedgames.com>> wrote:
>
>      Hi,
>
>     I'm performing tests with Cassandra 0.6.5 with Hector 0.6.0-14 on
>     a single machine (one node cluster). I've noticed an issue with
>     consistency.
>
>     In my tests I perform a KeySpace.batchMutate() to update a column
>     and immediately after that I perform a KeySpace.getSlice() on the
>     same column (from within the same thread). I noticed that
>     occasionally I get back the previous value rather than the value
>     I've just written.
>
>     My guess is that this occurs because Hector uses pooled
>     connections and both my requests are executed on different
>     connections. I suspect this causes a race condition in Cassandra
>     between the getSlice() and the batchMutate().
>
>     Can anyone confirm my suspicions and does anyone have a solution
>     for this?
>
>     Groets, Hugo.
>
>

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    I'm using QUORUM, but in my single-node setup this doesn't matter
    IMHO.<br>
    <br>
    On 9/3/2010 1:51 PM, Nick Telford wrote:
    <blockquote
      cite="mid:AANLkTikiHi1FvPr=Qb+=LEYF5Te1p=5saPDF1VpvUtAB@mail.gmail.com"
      type="cite">Which ConsistencyLevels did you use for your
      batchMutate() and getSlice() operations?
      <div><br>
      </div>
      <div>ConsistencyLevels directly dictate the level of consistency
        you will get with your data.</div>
      <div><br>
      </div>
      <div>Regards,</div>
      <div><br>
      </div>
      <div>Nick Telford<br>
        <br>
        <div class="gmail_quote">On 3 September 2010 12:03, Hugo <span
            dir="ltr">&lt;<a moz-do-not-send="true"
              href="mailto:hugo@unitedgames.com">hugo@unitedgames.com</a>&gt;</span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
            0.8ex; border-left: 1px solid rgb(204, 204, 204);
            padding-left: 1ex;">
            &nbsp;Hi,<br>
            <br>
            I'm performing tests with Cassandra 0.6.5 with Hector
            0.6.0-14 on a single machine (one node cluster). I've
            noticed an issue with consistency.<br>
            <br>
            In my tests I perform a KeySpace.batchMutate() to update a
            column and immediately after that I perform a
            KeySpace.getSlice() on the same column (from within the same
            thread). I noticed that occasionally I get back the previous
            value rather than the value I've just written.<br>
            <br>
            My guess is that this occurs because Hector uses pooled
            connections and both my requests are executed on different
            connections. I suspect this causes a race condition in
            Cassandra between the getSlice() and the batchMutate().<br>
            <br>
            Can anyone confirm my suspicions and does anyone have a
            solution for this?<br>
            <br>
            Groets, Hugo.<br>
          </blockquote>
        </div>
        <br>
      </div>
    </blockquote>
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