Question

我需要从包含二级索引的表中获取记录。但是我得到“错误请求：不支持带有第二个索引的ORDER BY”。错误。我知道cassandra服务器中的CQL3不支持此功能。如何实现此功能？

以下是我的表结构和索引创建和选择查询。

1.在cassandra中创建表：

    CREATE COLUMNFAMILY message_log(conversationid bigint,starttime timestamp,flag boolean,user_id text,expert_id text,conv_initiator_id text,message text,PRIMARY KEY(conversationid,starttime)) ;

2.创建索引： CREATE INDEX message_log_idx_conv_initiator_id ON message_log（conv_initiator_id）;

CREATE INDEX message_log_idx_flag ON message_log (flag);

3.从表中获取记录： select messageid，user_id，expert_id，来自message_log的消息，其中conv_initiator_id ='manoj@1921.168.1.64'AND flag = true ORDER BY starttime ASC允许过滤。

I get "Bad Request: ORDER BY with 2ndary indexes is not supported.", when I run 3rd query.

我的模块的Erlang部分是：

get_chat_history_by_userid（从） - ＆GT;

{ok, Pid} = seestar_session:start_link("localhost", 9042),      
QryUse = "USE mykeyspace;", 
case seestar_session:perform(Pid, QryUse, one) of 
    {ok,_Result} ->         
        FromJid = From#jid.luser++"@"++From#jid.lserver,            
        Flag = true,        
        QueryFinal=lists:concat(["select conversationid,user_id,expert_id,message from message_log 
        where conv_initiator_id = ","'",FromJid ,"'", " AND flag =",Flag," ORDER BY starttime ASC"," ALLOW FILTERING"]),            
            case seestar_session:perform(Pid,QueryFinal,one) of 
                {ok,_RecordList} ->                                  
                    {rows,_ColumnNames,_Records} = _RecordList,                     
                    ?INFO_MSG("selecting records from database using userid    ~p",[_Records]),
                    _Records;   
                {error,_Error} ->
                    ?INFO_MSG("Error occured while selecting records from database using userid~p",[_Error])
            end;                    
    {error,_Error} ->
        ?INFO_MSG(" Error occured while executing use query ~p",[_Error])
end.

错误请求：不支持带有第二个索引的ORDER BY

0 个答案: