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https://issues.apache.org/jira/browse/CASSANDRA-10214?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Sam Tunnicliffe updated CASSANDRA-10214:
----------------------------------------
Description:
(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)
was:
(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 v1_idx;
SELECT * FROM ks.t1 WHERE v1=0 AND v2=0 USING v2_idx;
SELECT * FROM ks.t1 WHERE v1=0 AND v2=0 USING 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.
> 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
> 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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