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From "Edward Capriolo (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CASSANDRA-6870) Transform operation
Date Wed, 19 Mar 2014 04:34:43 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6870?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13940156#comment-13940156
] 

Edward Capriolo edited comment on CASSANDRA-6870 at 3/19/14 4:33 AM:
---------------------------------------------------------------------

{code}
    ColumnTransform ct = new ColumnTransform();
      ct.setFunction_name("concat");
      ct.setInput_columns(Arrays.asList(ByteBufferUtil.bytes("a"),ByteBufferUtil.bytes("b")));
      ct.setOutput_column(ByteBufferUtil.bytes("a"));
{code}

Means pass cells a + b into udf named contat and write the results as column a. You can specify
a list of these in the request.


was (Author: appodictic):
{code}
    ColumnTransform ct = new ColumnTransform();
      ct.setFunction_name("concat");
      ct.setInput_columns(Arrays.asList(ByteBufferUtil.bytes("a"),ByteBufferUtil.bytes("b")));
      ct.setOutput_column(ByteBufferUtil.bytes("a"));
{code}

Means pass cells a + b into udf named contact and write the results as column a. You can specify
a list of these in the request.

> Transform operation
> -------------------
>
>                 Key: CASSANDRA-6870
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6870
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Edward Capriolo
>            Assignee: Edward Capriolo
>            Priority: Minor
>
> Compare and swap uses paxos to only update a value only if some criteria is met. If I
understand correctly we should be able to use this feature to provide a wider variety of server
side operations. 
> For example inside a paxos transaction performing a slice and then using a function to
manipulate the slice. You could accomplish features like append and increment this way without
user needing to know the current value.
> I took a stab at doing this. I **think** I did it correctly. Comments welcome.



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