[jira] [Commented] (CASSANDRA-2231) Add CompositeType comparer to the comparers provided in org.apache.cassandra.db.marshal

["Ed Anuff (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-2231?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13012531#comment-13012531 ] 

Ed Anuff commented on CASSANDRA-2231:
-------------------------------------

Sylvain, in the JPA implementation, we're seeing that we'd like to have a little more flexibility with the trailing end-of-component, specifically, that it be able to have values of -1,0,1 rather than just 0,1.  The comparison logic would look like this:

{noformat}
byte b1 = bb1.get();
byte b2 = bb2.get();
if (b1 < 0) {
	if (b2 >= 0) {
		return -1;
	}
}

if (b1 > 0) {
	if (b2 <= 0) {
		return 1;
	}
}

if ((b1 == 0) && (b2 != 0)) {
	return - b2;
}
{noformat}



> Add CompositeType comparer to the comparers provided in org.apache.cassandra.db.marshal
> ---------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-2231
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2231
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Contrib
>    Affects Versions: 0.7.3
>            Reporter: Ed Anuff
>            Assignee: Sylvain Lebresne
>            Priority: Minor
>             Fix For: 0.7.5
>
>         Attachments: CompositeType-and-DynamicCompositeType.patch, edanuff-CassandraCompositeType-1e253c4.zip
>
>
> CompositeType is a custom comparer that makes it possible to create comparable composite values out of the basic types that Cassandra currently supports, such as Long, UUID, etc.  This is very useful in both the creation of custom inverted indexes using columns in a skinny row, where each column name is a composite value, and also when using Cassandra's built-in secondary index support, where it can be used to encode the values in the columns that Cassandra indexes.  One scenario for the usage of these is documented here: http://www.anuff.com/2010/07/secondary-indexes-in-cassandra.html.  Source for contribution is attached and has been previously maintained on github here: https://github.com/edanuff/CassandraCompositeType

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