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From "Aleksey Yeschenko (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6936) Make all byte representations of types comparable by their unsigned byte representation only
Date Wed, 04 Feb 2015 16:00:37 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14305353#comment-14305353
] 

Aleksey Yeschenko commented on CASSANDRA-6936:
----------------------------------------------

I'm hoping that just having CASSANDRA-8730 and CASSANDRA-8731 would be enough.

Many subtle and maybe not so subtle issues with converting representations under the hood
like this will come up.
One would be breaking timestamp ties in reconcile. To preserve old rules and avoid corruption
you'd have to convert the new representation back to the regular representation, and do a
comparison on that. So cells would now have to reference the type of the value, too.

bq. v4 protocol includes new serialization formats

Do you mean new types, or changing serialization format of the existing types? The latter
wouldn't be welcomed by driver authors.

> Make all byte representations of types comparable by their unsigned byte representation
only
> --------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-6936
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6936
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Benedict
>              Labels: performance
>             Fix For: 3.0
>
>
> This could be a painful change, but is necessary for implementing a trie-based index,
and settling for less would be suboptimal; it also should make comparisons cheaper all-round,
and since comparison operations are pretty much the majority of C*'s business, this should
be easily felt (see CASSANDRA-6553 and CASSANDRA-6934 for an example of some minor changes
with major performance impacts). No copying/special casing/slicing should mean fewer opportunities
to introduce performance regressions as well.
> Since I have slated for 3.0 a lot of non-backwards-compatible sstable changes, hopefully
this shouldn't be too much more of a burden.



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