Ahmed Bashir created CASSANDRA-5419:
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Summary: 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
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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