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在CQL上使用IN运算符分区键和（聚类键或索引列）

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我有一个警报表 . 我想在2列上使用IN运算符并在一列上使用大于运算符来查询它 . 我没试过下面的事情 . 有人可以告诉我DB设计使查询工作吗？我的环境细节：[cqlsh 5.0.1 | Cassandra 2.1.2 | CQL规范3.2.0 |原生协议v3]

在分区键中使用'type'：

CREATE TABLE alerts (
    serialNumber text,
    time bigint,
    type text,
    time2 int,
    status text,
    parentId int,
    PRIMARY KEY ((serialNumber,type), time)
 ) WITH CLUSTERING ORDER BY (time DESC);

cqlsh:testdb> select * from alerts WHERE serialNumber IN ( '1','2') AND type IN ( '1','2','3' ) AND time > 1;
code=2200 [Invalid query] message="Partition KEY part serialNumber cannot be restricted by IN relation (only the last part of the partition key can)"

使用聚类键中的“类型”：

CREATE TABLE alerts (
    serialNumber text,
    time bigint,
    type text,
    time2 int,
    status text,
    parentId int,
    PRIMARY KEY (serialNumber, type, time)
) WITH CLUSTERING ORDER BY (type ASC,time DESC);

cqlsh:testdb> select * from alerts WHERE serialnumber IN ( '1','2') AND type IN ( 'a','b') and time > 1;
code=2200 [Invalid query] message="Clustering column "type" cannot be restricted by an IN relation"

索引类型：

CREATE TABLE alerts (
    serialNumber text,
    time bigint,
    type text,
    time2 int,
    status text,
    parentId int,
    PRIMARY KEY (serialNumber, time)
) WITH CLUSTERING ORDER BY (time DESC);
CREATE INDEX alertsTypeIndex ON alerts(type);

select * from alerts WHERE serialnumber IN ( '1','2') and time > 1 AND type IN ( 'a','b');
code=2200 [Invalid query] message="IN predicates on non-primary-key columns (type) is not yet supported"

select * from alerts WHERE serialnumber IN ( '1','2') and time > 1 AND type = 'a';
code=2200 [Invalid query] message="Select on indexed columns and with IN clause for the PRIMARY KEY are not supported"
cassandra cql cassandra-2.0 cql3

1 回答

  • 2

    你在哪个版本？你的第二个例子在2.2.1中为我工作：

    Connected to VaporTrails at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 2.2.1 | CQL spec 3.3.0 | Native protocol v4]
Use HELP for help.
aploetz@cqlsh> use stackoverflow ;
aploetz@cqlsh:stackoverflow> CREATE TABLE alerts (
                 ...     serialNumber text,
                 ...     time bigint,
                 ...     type text,
                 ...     time2 int,
                 ...     status text,
                 ...     parentId int,
                 ...     PRIMARY KEY (serialNumber, type, time)
                 ... ) WITH CLUSTERING ORDER BY (type ASC,time DESC);
aploetz@cqlsh:stackoverflow> INSERT INTO alerts (serialnumber , time,type,time2, status, parentid) VALUES ('1',0,'1',1,'1',1);
aploetz@cqlsh:stackoverflow> INSERT INTO alerts (serialnumber , time,type,time2, status, parentid) VALUES ('2',2,'2',2,'2',2);
aploetz@cqlsh:stackoverflow> INSERT INTO alerts (serialnumber , time,type,time2, status, parentid) VALUES ('3',3,'3',3,'3',3);
aploetz@cqlsh:stackoverflow> select * from alerts WHERE serialNumber IN ( '1','2') AND type IN ( '1','2','3' ) AND time > 1;

 serialnumber | type | time | parentid | status | time2
--------------+------+------+----------+--------+-------
            2 |    2 |    2 |        2 |      2 |     2

(1 rows)

    即使你可以让它工作，我也会建议反对它 . 在分区键上使用IN关键字称为"multi-key"查询反模式 . DataStax有blurb in their documentation discussing why this is bad . 实质上，这种方法不能扩展，因为必须查询许多节点才能满足这些类型的查询 . 您应该找到另一种方法来建模警报，这样您就不需要使用IN关系 .

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