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From "Jay Patel (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-8855) Batching SELECTs for multiple column ranges for the same partition key
Date Tue, 24 Feb 2015 05:39:14 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-8855?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jay Patel updated CASSANDRA-8855:
---------------------------------
    Summary:  Batching SELECTs for multiple column ranges for the same partition key  (was:
 Batching SELECTs )

>  Batching SELECTs for multiple column ranges for the same partition key
> -----------------------------------------------------------------------
>
>                 Key: CASSANDRA-8855
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8855
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Jay Patel
>
> SELECT’s IN clause allows to batch selects for multiple partition keys of a given table.
Can we consider supporting batch select for multiple column ranges for a given partition key?
> For instance, would like to batch below two or more SELECTs for a given partition key
“event_type” and the different ranges of the “time”:
> SELECT value
> FROM events
> WHERE event_type = 'myEvent'
>   AND time > '2011-02-03'
>   AND time <= '2012-01-01'
> SELECT value
> FROM events
> WHERE event_type = 'myEvent'
>   AND time > '2012-02-03'
>   AND time <= '2013-01-01’
> One way to optimize these is to fire multiple SELECTs in parallel & async from the
application, but by batching them we can do further optimizations such as avoid multiple round
trips; from app server to C*, and even from coordinator to the replicas. Once request is received
by the target replicas, we can return all the ranges requested for a particular partition
key in one shot. 
> This will be very useful for some of the use cases we're working on. I can take a first
cut at this if no concerns.
> In addition, how about supporting batch for multiple SELECTs across tables. I think that
will require more changes in ResultSet and may not have lot of opportunities for optimizations.
However, at least it will help to avoid multiple round trips from app server to the C*.
> Thoughts welcome. Thanks!



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