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From "Sam Tunnicliffe (JIRA)" <j...@apache.org>
Subject [jira] [Assigned] (CASSANDRA-10214) Enable index selection to be overridden on a per query basis
Date Thu, 24 Sep 2015 04:45:04 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-10214?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Sam Tunnicliffe reassigned CASSANDRA-10214:
-------------------------------------------

    Assignee: Sam Tunnicliffe

> Enable index selection to be overridden on a per query basis
> ------------------------------------------------------------
>
>                 Key: CASSANDRA-10214
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10214
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Sam Tunnicliffe
>            Assignee: Sam Tunnicliffe
>             Fix For: 3.x
>
>
> (Broken out of CASSANDRA-10124)
> We could add a {{USING INDEX <indexname>}} clause to {{SELECT}} syntax to force
the choice of index and bypass the usual index selection mechanism.
> {code}
> CREATE TABLE ks.t1(k int, v1 int, v2 int, PRIMARY KEY (k));
> CREATE INDEX v1_idx ON ks.t1(v1);
> CREATE INDEX v2_idx ON ks.t1(v2);
> CREATE CUSTOM INDEX v1_v2_idx ON ks.t1(v1, v2) USING 'com.foo.bar.CustomMultiColumnIndex';
> # Override internal index selection mechanism
> SELECT * FROM ks.t1 WHERE v1=0 AND v2=0 USING INDEX v1_idx;
> SELECT * FROM ks.t1 WHERE v1=0 AND v2=0 USING INDEX v2_idx;
> SELECT * FROM ks.t1 WHERE v1=0 AND v2=0 USING INDEX v1_v2_idx;
> {code}
> This is in some ways similar to [index hinting|http://docs.oracle.com/cd/B19306_01/server.102/b14211/hintsref.htm#CHDJDIAH]
in Oracle. 
> edit: fixed typo's (missing INDEX in the USING clauses)



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