Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@cassandra.apache.org
MIME-Version: 1.0
In-Reply-To: <CACWHCD+EK62RYpwXozf3oudNakUSpkJ+F6-0WJ=3Pv2Czki0MA@mail.gmail.com>
References: <CAKiMtbcwcn-+zUm-yriCXWmJfREYi7pP8r4V2=z0Wrh-CxU6rQ@mail.gmail.com>
 <CACWHCD+EK62RYpwXozf3oudNakUSpkJ+F6-0WJ=3Pv2Czki0MA@mail.gmail.com>
From: Ali Akhtar <ali.rac200@gmail.com>
Date: Sun, 13 Nov 2016 17:25:58 +0500
Message-ID: <CAKiMtbcvqqXJ9H02neu9q5WqKVU4Zzx12tbbcgi7RYH4=tk+QA@mail.gmail.com>
Subject: Re: Consistency when adding data to collections concurrently?
To: user@cassandra.apache.org
Content-Type: multipart/alternative; boundary=047d7b873f806961af05412dd334
archived-at: Sun, 13 Nov 2016 12:26:07 -0000

--047d7b873f806961af05412dd334
Content-Type: text/plain; charset=UTF-8

If I wanted to get all values for an item, including its labels, how would
that be done in the above case?

Also can you make a UDT a clustered key?

On Sun, Nov 13, 2016 at 4:33 AM, Manoj Khangaonkar <khangaonkar@gmail.com>
wrote:

> Hi,
>
> Instead of using a collection, consider making label a clustered column.
>
> With this each request will essentially append a column (label) to the
> partition.
>
> To get all labels would be a simple query
>
> select label from table where partitionkey = "value".
>
> In general , read + update  of a column is an anti pattern in cassandra -
> which is what you are doing. What I suggesting
> above is appending more columns and not updating existing columns.
>
> regards
>
> regards
>
> On Sat, Nov 12, 2016 at 2:34 AM, Ali Akhtar <ali.rac200@gmail.com> wrote:
>
>> I have a table where each record contains a list<string> of labels.
>>
>> I have an endpoint which responds to new labels being added to a record
>> by the user.
>>
>> Consider the following scenario:
>>
>> - Record X, labels = []
>> - User selects 2 labels, clicks a button, and 2 http requests are
>> generated.
>> - The server receives request for Label 1 and Label 2 at the same time.
>> - Both requests see the labels as empty, add 1 label to the collection,
>> and send it.
>> - Record state as label 1 request sees it: [1], as label 2 sees it: [2]
>>
>> How will the above conflict be resolved? What can I do so I end up with
>> [1, 2] instead of either [1] or [2] after both requests have been processed?
>>
>
>
>
> --
> http://khangaonkar.blogspot.com/
>

--047d7b873f806961af05412dd334
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">If I wanted to get all values for an item, including its l=
abels, how would that be done in the above case?<div><br></div><div>Also ca=
n you make a UDT a clustered key?</div></div><div class=3D"gmail_extra"><br=
><div class=3D"gmail_quote">On Sun, Nov 13, 2016 at 4:33 AM, Manoj Khangaon=
kar <span dir=3D"ltr">&lt;<a href=3D"mailto:khangaonkar@gmail.com" target=
=3D"_blank">khangaonkar@gmail.com</a>&gt;</span> wrote:<br><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex"><div dir=3D"ltr"><div><div><div><div><div>Hi,<br><br></div>I=
nstead of using a collection, consider making label a clustered column.<br>=
<br></div>With this each request will essentially append a column (label) t=
o the partition.<br><br></div>To get all labels would be a simple query<br>=
<br></div>select label from table where partitionkey =3D &quot;value&quot;.=
<br><br></div><div>In general , read + update=C2=A0 of a column is an anti =
pattern in cassandra - which is what you are doing. What I suggesting<br></=
div><div>above is appending more columns and not updating existing columns.=
<br><br></div><div>regards<br></div><div><br></div>regards<br></div><div cl=
ass=3D"gmail_extra"><div><div class=3D"h5"><br><div class=3D"gmail_quote">O=
n Sat, Nov 12, 2016 at 2:34 AM, Ali Akhtar <span dir=3D"ltr">&lt;<a href=3D=
"mailto:ali.rac200@gmail.com" target=3D"_blank">ali.rac200@gmail.com</a>&gt=
;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 =
.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr">I have a=
 table where each record contains a list&lt;string&gt; of labels.<div><br><=
/div><div>I have an endpoint which responds to new labels being added to a =
record by the user.</div><div><br></div><div>Consider the following scenari=
o:</div><div><br></div><div>- Record X, labels =3D []</div><div>- User sele=
cts 2 labels, clicks a button, and 2 http requests are generated.</div><div=
>- The server receives request for Label 1 and Label 2 at the same time.</d=
iv><div>- Both requests see the labels as empty, add 1 label to the collect=
ion, and send it.</div><div>- Record state as label 1 request sees it: [1],=
 as label 2 sees it: [2]</div><div><br></div><div>How will the above confli=
ct be resolved? What can I do so I end up with [1, 2] instead of either [1]=
 or [2] after both requests have been processed?</div></div>
</blockquote></div><br><br clear=3D"all"><br></div></div><span class=3D"HOE=
nZb"><font color=3D"#888888">-- <br><div class=3D"m_-3346782449632582646gma=
il_signature" data-smartmail=3D"gmail_signature"><a href=3D"http://khangaon=
kar.blogspot.com/" target=3D"_blank">http://khangaonkar.blogspot.<wbr>com/<=
/a></div>
</font></span></div>
</blockquote></div><br></div>

--047d7b873f806961af05412dd334--