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From "sankalp kohli (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7344) Read at SERIAL can lead to unnecessary contention
Date Thu, 19 Jun 2014 01:10:24 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7344?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14036778#comment-14036778
] 

sankalp kohli commented on CASSANDRA-7344:
------------------------------------------

By getting the last accepted commit and seeing whether it is empty. 
If it is not, then do a prepare and do like we do now. 
I am not sure why prepare phase is necessary to find out whether there is anything inflight/pending
to be committed. 

> Read at SERIAL can lead to unnecessary contention 
> --------------------------------------------------
>
>                 Key: CASSANDRA-7344
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7344
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: sankalp kohli
>            Assignee: sankalp kohli
>            Priority: Minor
>
> If two clients are doing a read at serial on the same row, it does a full prepare step
to figure out whether there is any updates or cas in flight or uncompleted. 
> This can cause contention between then leading to waste of time in retrying. One of the
request will not get a promise and will need to sleep. 
> Instead they can check whether there is anything to finish and if not continue. 
> If there is something to be done, then they can do the full prepare. 



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