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https://issues.apache.org/jira/browse/CASSANDRA-5419?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-5419:
--------------------------------------
Comment: was deleted
(was: Detecting diffs smaller than a row is actually the hard part. (See
link.))
> Employ column differencing (as done for read repairs) during node repairs
> --------------------------------------------------------------------------
>
> Key: CASSANDRA-5419
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5419
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 1.1.10
> Environment: Production
> Reporter: Ahmed Bashir
> Labels: compaction, repair
>
> In particular for wide rows, the headroom required for node repairs can be
> substantial given that entire rows are streamed for any and all row hash
> discrepancies.
> This headroom must be sustained until compaction slowly compacts these newly
> streamed SSTables and reduces the overall load on each instance.
> The overall footprint of node repairs would be greatly reduced if we employed
> differencing at the column level and sent over row mutations, similar to what
> is done during read repair. This is a great alternative for deployments
> wherein sending over entire rows rather than the deltas is not an option.
> Since node repairs can now specify start and end tokens (i.e. subrange
> repairs), the additional computation can be broken down easily, and it's a
> welcome trade-off for significantly less streaming, compaction, and temporary
> headroom requirements.
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