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Posted to commits@cassandra.apache.org by "Tyler Hobbs (JIRA)" <ji...@apache.org> on 2014/05/27 18:14:02 UTC
[jira] [Updated] (CASSANDRA-6875) CQL3: select multiple CQL rows in
a single partition using IN
[ https://issues.apache.org/jira/browse/CASSANDRA-6875?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tyler Hobbs updated CASSANDRA-6875:
-----------------------------------
Attachment: 6875-part2.txt
Good analysis, [~wtmitchell3]. We shouldn't need to adjust the bound for the comparator at all for IN queries (and the iterator was obviously being used incorrectly anyway). 6875-part2.txt fixes that and adds some unit test coverage for IN queries on reversed comparators and IN queries with more items than the number of components in the comparator..
> CQL3: select multiple CQL rows in a single partition using IN
> -------------------------------------------------------------
>
> Key: CASSANDRA-6875
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6875
> Project: Cassandra
> Issue Type: Bug
> Components: API
> Reporter: Nicolas Favre-Felix
> Assignee: Tyler Hobbs
> Priority: Minor
> Fix For: 2.0.9, 2.1 rc1
>
> Attachments: 6875-part2.txt
>
>
> In the spirit of CASSANDRA-4851 and to bring CQL to parity with Thrift, it is important to support reading several distinct CQL rows from a given partition using a distinct set of "coordinates" for these rows within the partition.
> CASSANDRA-4851 introduced a range scan over the multi-dimensional space of clustering keys. We also need to support a "multi-get" of CQL rows, potentially using the "IN" keyword to define a set of clustering keys to fetch at once.
> (reusing the same example\:)
> Consider the following table:
> {code}
> CREATE TABLE test (
> k int,
> c1 int,
> c2 int,
> PRIMARY KEY (k, c1, c2)
> );
> {code}
> with the following data:
> {code}
> k | c1 | c2
> ---+----+----
> 0 | 0 | 0
> 0 | 0 | 1
> 0 | 1 | 0
> 0 | 1 | 1
> {code}
> We can fetch a single row or a range of rows, but not a set of them:
> {code}
> > SELECT * FROM test WHERE k = 0 AND (c1, c2) IN ((0, 0), (1,1)) ;
> Bad Request: line 1:54 missing EOF at ','
> {code}
> Supporting this syntax would return:
> {code}
> k | c1 | c2
> ---+----+----
> 0 | 0 | 0
> 0 | 1 | 1
> {code}
> Being able to fetch these two CQL rows in a single read is important to maintain partition-level isolation.
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