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https://issues.apache.org/jira/browse/CASSANDRA-10307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17154367#comment-17154367
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ZhaoYang commented on CASSANDRA-10307:
--------------------------------------

the lock contention issue will not be a problem in thread-per-core 
architecture, but the lock is still needed to prevent racing with the previous 
insertion that is waiting for async io from read-before-write.

> Avoid always locking the partition key when a table has a materialized view
> ---------------------------------------------------------------------------
>
>                 Key: CASSANDRA-10307
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10307
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Feature/Materialized Views
>            Reporter: T Jake Luciani
>            Priority: Normal
>              Labels: materializedviews
>             Fix For: 4.x
>
>
> When a table has associated materialized views we must restrict other 
> concurrent changes to the affected rows.  We currently lock the entire 
> partition.  
> The issue is many updates to the same partition on the base table is now 
> serialized effectively.
> We can't lock the primary key instead due to range tombstones cover a range 
> of rows.
> If we created (or perhaps reuse if already exists) a clustering range class 
> we can lock at this level. 



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