[jira] [Updated] (CASSANDRA-14002) Don't use SHA256 when building merkle trees

2017-11-08 Thread Marcus Eriksson (JIRA) 

 [ 
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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[jira] [Updated] (CASSANDRA-14002) Don't use SHA256 when building merkle trees

2017-11-08 Thread Michael Kjellman (JIRA) 

 [ 
https://issues.apache.org/jira/browse/CASSANDRA-14002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Michael Kjellman updated CASSANDRA-14002:
-
Reviewer: Michael Kjellman

> 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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[jira] [Updated] (CASSANDRA-14002) Don't use SHA256 when building merkle trees

2018-03-04 Thread Marcus Eriksson (JIRA) 

 [ 
https://issues.apache.org/jira/browse/CASSANDRA-14002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Marcus Eriksson updated CASSANDRA-14002:

   Resolution: Fixed
Fix Version/s: (was: 4.x)
   4.0
   Status: Resolved  (was: Patch Available)

and committed as {{68b81372cd838808b304d58677cdc86f6ec35ffa}}, thanks!

> 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
>Priority: Major
> Fix For: 4.0
>
>
> 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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