Benedict created CASSANDRA-7520:
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Summary: Permit sorting sstables by raw partition key, as opposed
to token
Key: CASSANDRA-7520
URL: https://issues.apache.org/jira/browse/CASSANDRA-7520
Project: Cassandra
Issue Type: Improvement
Components: Core
Reporter: Benedict
At the moment we have some counter-intuitive behaviour, which is that with a
hashed partitioner (recommended) the more compacted the data is, the more
randomly distributed it is amongst the file. This means that data access
locality is made pretty much as bad as possible, and we rely on the OS to do
its best to fix that for us with its page cache.
[~jasobrown] mentioned this at the NGCC, but thinking on it some more it seems
that many use cases may benefit from dropping the token at the storage level
and sorting based on the raw key data. For workloads where nearness of key =>
likelihood of being coreferenced, this could improve data locality and cache
hit rate dramatically. Timeseries workloads spring to mind, but I doubt this is
constrained to them. Most likely any non-random access pattern could benefit. A
random access pattern would most likely suffer from this scheme, as we can
index more efficiently into the hashed data. However there's no reason we could
not support both schemes.
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