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Michael Shuler commented on CASSANDRA-9602: ------------------------------------------- [~thobbs] could you discuss this as a possible improvement for READ at EACH_QUORUM? > EACH_QUORUM READ support needed > ------------------------------- > > Key: CASSANDRA-9602 > URL: https://issues.apache.org/jira/browse/CASSANDRA-9602 > Project: Cassandra > Issue Type: Improvement > Reporter: Scott Guminy > Assignee: Tyler Hobbs > Fix For: 3.x > > > EACH_QUORUM consistency for READ should be added. > This bug https://issues.apache.org/jira/browse/CASSANDRA-3272 says it is not > needed ever, however I have a use case where I need it. I think the decision > made was incorrect. Here's why... > > My application has two key pieces: > > # *End user actions* which add/modify data in the system. End users > typically access the application from only one Data Center and only see their > own data > # *Scheduled business logic tasks* which run from any node in any data > center. These tasks process data added by the end users in an asynchronous > way > > *End user actions must have the highest degree of availability.* Users must > always be able to add data to the system. The data will be processed later. > To support this, end user actions will use *LOCAL_QUORUM Read and Write > Consistency*. > > Scheduled tasks don't need to have a high degree of availability but MUST > operate on the most up to date data. *The tasks will run with EACH_QUORUM* > to ensure that no matter how many data centers we have, we always READ the > latest data. This approach allows us some amount of fault tolerance. > > The problem is that EACH_QUORUM is not a valid READ consistency level. This > mean I have no alternative but to use ALL. ALL will work, but is not the > best since it offers support for ZERO failures. I would prefer EACH_QUORUM > since it can support some failures in each data center. -- This message was sent by Atlassian JIRA (v6.3.4#6332)