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https://issues.apache.org/jira/browse/CASSANDRA-1487?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jignesh Dhruv updated CASSANDRA-1487:
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Attachment: QuorumResponseHandler.java.patch
QuoromResponseHandler Patch.
> Bug in calculating QUORUM
> -------------------------
>
> Key: CASSANDRA-1487
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1487
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 0.7 beta 1
> Reporter: Jignesh Dhruv
> Attachments: QuorumResponseHandler.java.patch
>
>
> Hello,
> It seems that there is a bug in calculating QUORUM in
> src/java/org/apache/cassandra/service/QuorumResponseHandler.java
> Currently the QUORUM formula in place will return correct QUORUM if
> replication factor <= 3. However if you have a Replication Factor > 3, it
> will return incorrect result.
> -----------------------
> --- src/java/org/apache/cassandra/service/QuorumResponseHandler.java
> (revision 995482)
> +++ src/java/org/apache/cassandra/service/QuorumResponseHandler.java
> (working copy)
> @@ -109,7 +109,7 @@
> case ANY:
> return 1;
> case QUORUM:
> - return (DatabaseDescriptor.getQuorum(table)/ 2) + 1;
> + return DatabaseDescriptor.getQuorum(table);
> case ALL:
> return DatabaseDescriptor.getReplicationFactor(table);
> default:
> -------------------
> In QuorumResponseHandler:determineBlockFor()
> DatabaseDescriptor.getQuorum(table) is already returning a quorum value which
> is further divided by 2 and a one is added.
> So say if your RF=6, it is suppose to check 4 replicas, (6/2)+1=4 but it ends
> up checking only 3 replicas as DatabaseDescriptor.getQuorum returns 4, so
> determineBlockFor will return (4/2)+1=3.
> Let me know if you have any questions.
> Jignesh
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