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From: Ike Walker <ike.walker@flite.com>
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Subject: CQL workaround for modifying a primary key
Message-Id: <96D788E5-39B3-4C4B-A6D3-EF728A453867@flite.com>
Date: Tue, 3 Dec 2013 17:23:55 -0500
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
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What is the best practice for modifying the primary key definition of a =
table in Cassandra 1.2.9?

Say I have this table:

CREATE TABLE temperature (
   weatherstation_id text,
   event_time timestamp,
   temperature text,
   PRIMARY KEY (weatherstation_id,event_time)
);

I want to add a new column named version and include that column in the =
primary key.

CQL will let me add the column, but you can't change the primary key for =
an existing table.

So I drop the table and recreate it:

DROP TABLE temperature;

CREATE TABLE temperature (
   weatherstation_id text,
   version int,
   event_time timestamp,
   temperature text,
   PRIMARY KEY (weatherstation_id,version,event_time)
);

But then I start getting errors like this:

java.io.FileNotFoundException: =
/var/lib/cassandra/data/test/temperature/test-temperature-ic-8316-Data.db =
(No such file or directory)

So I guess the drop table doesn't actually delete the data, and I end up =
with a problem like this:

https://issues.apache.org/jira/browse/CASSANDRA-4857

What's a good workaround for this, assuming I don;t want to change the =
name of my table? Should I just truncate the table, then drop it and =
recreate it?

Thanks.

-Ike Walker=

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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">What =
is the best practice for modifying the primary key definition of a table =
in Cassandra 1.2.9?<div><br></div><div>Say I have this =
table:</div><div><br></div><div>CREATE TABLE temperature =
(</div><div>&nbsp; &nbsp;weatherstation_id text,</div><div>&nbsp; =
&nbsp;event_time timestamp,</div><div>&nbsp; &nbsp;temperature =
text,</div><div>&nbsp; &nbsp;PRIMARY KEY =
(weatherstation_id,event_time)</div><div>);</div><div><br></div><div>I =
want to add a new column named version and include that column in the =
primary key.</div><div><br></div><div>CQL will let me add the column, =
but you can't change the primary key for an existing =
table.</div><div><br></div><div>So I drop the table and recreate =
it:</div><div><br></div><div><div>DROP TABLE =
temperature;</div><div><br></div><div>CREATE TABLE temperature =
(</div><div>&nbsp; &nbsp;weatherstation_id text,</div><div>&nbsp; =
&nbsp;version int,</div><div>&nbsp; &nbsp;event_time =
timestamp,</div><div>&nbsp; &nbsp;temperature text,</div><div>&nbsp; =
&nbsp;PRIMARY KEY =
(weatherstation_id,version,event_time)</div><div>);</div></div><div><br></=
div><div>But then I start getting errors like =
this:</div><div><br></div><div><div>java.io.FileNotFoundException: =
/var/lib/cassandra/data/test/temperature/test-temperature-ic-8316-Data.db =
(No such file or directory)</div></div><div><br></div><div>So I guess =
the drop table doesn't actually delete the data, and I end up with a =
problem like this:</div><div><br></div><div><a =
href=3D"https://issues.apache.org/jira/browse/CASSANDRA-4857" =
title=3D"https://issues.apache.org/jira/browse/CASSANDRA-4857" =
style=3D"word-wrap: break-word; text-rendering: optimizelegibility; =
color: rgb(0, 51, 204); font-family: LucidaGrande; line-height: 18px; =
">https://issues.apache.org/jira/browse/CASSANDRA-4857</a></div><div><br><=
/div><div>What's a good workaround for this, assuming I don;t want to =
change the name of my table? Should I just truncate the table, then drop =
it and recreate =
it?</div><div><br></div><div>Thanks.</div><div><br></div><div>-Ike =
Walker</div></body></html>=

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