小编LoS*_*ano的帖子

我正在分析MongoDB数据源以检查其质量.我想知道每个文档是否包含属性time:所以我使用了这两个命令

> db.droppay.find().count();  
291822   
> db.droppay.find({time: {$exists : true}}).count()   
293525

如何使用给定字段的元素多于整个集合中包含的元素？出了什么问题？我无法找到错误.如果有必要,我可以发布文件的预期结构.

Mongo Shell版本是1.8.3.Mongo Db版本是1.8.3.

提前致谢

这是文档条目的预期结构:

{
  "_id" : ObjectId("4e6729cc96babe974c710611"), 
  "action" : "send",
  "event" : "sent",
  "job_id" : "50a1b7ac-7482-4ad6-ba7d-853249d6a123",    
  "result_code" : "0",
  "sender" : "",
  "service" : "webcontents",
  "service_name" : "webcontents",
  "tariff" : "0",
  "time" : "2011-09-07 10:22:35",
  "timestamp" : "1315383755",
  "trace_id" : "372",
  "ts" : "2011-09-07 09:28:42"
}

我很确定这很简单.我只是想从另一个空格中返回一个字符串.

public static void LinkWorker(string baseURLString)
{
     // do some stuff here
     HTMLWork(baseURLStringCycle)
     --> this is where i need xstring returned
     foreach(string xyString in xstring.split('\n'))
     {
     }
}

public static void HTMLWork(string baseURLStringCycle)
{
     //do HTML work here
     // create x string
     string xString = ; //the result of the htmlwork
}

我在以下行之后遇到了段错误:

this->my_set.insert(my_string);

该集已初始化,它包含std :: string.插入字符串不是指一个dandling指针,它是以null结尾的.集合中包含的所有其他字符串都不为null,并以'\ 0'结尾.

这是回溯:

#0  0xb7076bdb in std::_Rb_tree_insert_and_rebalance () from /usr/lib/libstdc++.so.6
#1  0xb7480795 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_M_insert_ (
    this=0x97bf918, __x=0x0, __p=0x980aa78, __v=@0xaabfc1c4) at /usr/include/c++/4.3/bits/stl_tree.h:854<br/>
#2  0xb7480b96 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_M_insert_unique (this=0x97bf918, __v=@0xaabfc1c4) at /usr/include/c++/4.3/bits/stl_tree.h:1148
#3  0xb74fab2d in std::set<std::string, std::less<std::string>, std::allocator<std::string> >::insert (this=0x97bf918, __x=@0xaabfc1c4)
    at /usr/include/c++/4.3/bits/stl_set.h:381

任何的想法？

编辑

更多代码:

set<string> dangerous_messages; //placed in header file

            qpid::client::Message msg;
            msg = (*mylocal_queues)[queue]->get(10*1e9);
            string msgUID = msg.getHeaders().getAsString("UID");
            if(this->dangerous_messages.count(msgUID))
            {
                       warning("(read_local_queue) Duplicate message \""+msgUID+"\" discarded");
           } …