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I know that I can define clustering order when I create a table by cql as code below:

create table test(
id int,
time timestamp,
value text,
primary key(id,time)) with clustering order by (time desc)

but I want change the clustering for table test after its creation with alter:

alter table  test
with clustering order by (item asc)

but I got error by that. Thanks for any help.

Has QUIT--Anony-Mousse
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S.Mohamed Mahdi Ahmadian zadeh
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2 Answers2

18

Changing the clustering order would require rewriting all your data on disk in a different order. The standard way to do this is to leverage Spark with the Cassandra Spark Connector: https://github.com/datastax/spark-cassandra-connector

Alternatively, if you're early in your dev process or it's a relatively small amount of data, you can use the bulk loader to throw it into a new table: https://docs.datastax.com/en/dsbulk/doc/

jbellis
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  • Hey, thanks for your answer! I assume this is still valid in recent versions of Cassandra? And is there an easy way to bulk-load? – tftd Apr 23 '21 at 13:58
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    You're welcome! I'm a little surprised that this is still useful 8 years later. I've edited it with links to some tools that may help. – jbellis May 03 '21 at 14:49
0

You may also change your CQL SELECT query to ORDER BY ASC without altering the table.

Ergin
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