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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6839) Support non equal conditions (for LWT)
Date Thu, 14 Aug 2014 22:23:19 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6839?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14097793#comment-14097793
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Tyler Hobbs commented on CASSANDRA-6839:
----------------------------------------

Sorry for the delay, the rebase for 2.1 is taking longer than I expected.

While working on tests, I realized that the only reason we define {{equals()}} on bounds is
for detecting "incompatible" conditions on the same column.  However, with these changes,
just because two conditions are not equal does not mean they are incompatible.  For example,
you might have {{IF a > 0 AND a IN (-100, 200)}}.  You probably won't write that by hand,
but it's easy to imagine scenarios where that's generated by code.

I would like to remove the check for incompatible conditions along with {{equals()}} for the
Bounds classes.  If two conditions really are incompatible, the operation just won't apply.
 Even if we had a magically perfect check for incompatibility, I don't think it's proper to
throw an IRE there.

> Support non equal conditions (for LWT)
> --------------------------------------
>
>                 Key: CASSANDRA-6839
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6839
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Sylvain Lebresne
>            Assignee: Tyler Hobbs
>            Priority: Minor
>             Fix For: 2.0.10
>
>         Attachments: 6839-v2.txt, 6839-v3.txt, 6839.txt
>
>
> We currently only support equal conditions in conditional updates, but it would be relatively
trivial to support non-equal ones as well. At the very least we should support '>', '>=',
'<' and '<=', though it would probably also make sense to add a non-equal relation too
('!=').



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