Question

我有下表：

CREATE TABLE dove.backend_events (
log_time_local timeuuid,
username text,
log_type text,
log_time timestamp,
device_category text,
log text,
device_details frozen<map<text, text>>,
PRIMARY KEY (log_time_local, username, device_details)
);

我正在运行此查询：SELECT * FROM dove.backend_events WHERE device_details['category'] = 'mobile' ALLOW FILTERING;

我收到此错误：InvalidRequest: code=2200 [Invalid query] message="Map-entry equality predicates on frozen map column device_details are not supported"

是什么导致它，我该如何解决？ <{1}}不是主键的一部分且未冻结时，不会发生此错误。

Answer 1

您可以为device_details添加索引，而不是将其设置为主键（并且不冻结它）：

CREATE TABLE dove.backend_events (
log_time_local timeuuid,
username text,
log_type text,
log_time timestamp,
device_category text,
log text,
device_details map<text, text>,
PRIMARY KEY (log_time_local, username)
);

CREATE INDEX dove.device_details_index ON dove.backend_events (ENTRIES(device_details));

通过这种方式，您可以有效地运行查询，而无需使用ALLOW FILTERING：

SELECT * FROM dove.backend_events WHERE device_details['category'] = 'mobile';

Cassandra无效查询＆＃34;不支持冻结地图列device_details上的地图条目等式谓词＆＃34;

1 个答案: