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https://issues.apache.org/jira/browse/CASSANDRA-6870?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13940156#comment-13940156
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Edward Capriolo commented on CASSANDRA-6870:
--------------------------------------------
{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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