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https://issues.apache.org/jira/browse/CASSANDRA-14002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Marcus Eriksson updated CASSANDRA-14002:
----------------------------------------
Status: Patch Available (was: Open)
Patch for this
[here|https://github.com/krummas/cassandra/commits/marcuse/nosharepairs] - it
replaces the SHA-256 with Murmur3.
Murmur3 is only 128 bit though, so the patch instead hashes every value twice
using 2 different murmur3 instances with different seeds to get the same number
of bits as SHA-256. The approach used is similar to what guava does in its
ConcatenatedHashFunction.
In my tests with semi-wide partitions (~100KB mean partition size) this reduces
the time spent building merkle trees with at least 50%.
https://builds.apache.org/view/A-D/view/Cassandra/job/Cassandra-devbranch-dtest/422/
https://circleci.com/gh/krummas/cassandra/173
cc [~mkjellman]
> Don't use SHA256 when building merkle trees
> -------------------------------------------
>
> Key: CASSANDRA-14002
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14002
> Project: Cassandra
> Issue Type: Bug
> Reporter: Marcus Eriksson
> Assignee: Marcus Eriksson
> Fix For: 4.x
>
>
> We should avoid using SHA-2 when building merkle trees as we don't need a
> cryptographic hash function for this.
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