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我创建了map/reduce函数以将任务分组结果放入一个结果对象中。我使用pyymongo库在Python中写入:MongoDB Map/Reduce引发异常:失败:db断言失败
m = Code("""function() {
data = {};
res = ''
if(this.result_id) {
res={'objectid':this.result_id.toString()};
} else {
res=this.result;
}
emit(this.data, res);
}""")
r = Code("""function(k,values) {
data={};
for(var i=0; i<values.length; i++) {
for(attr in values[i])
data[attr]=values[i][attr];
}
return data
}""")
而且我需要该结果对象与输入任务查询的顺序相同。但是当我使用排序PARAM中要求:
res = db.tasks.map_reduce(m, r, query={'job_id':job_id},sort={'position':pymongo.ASCENDING})
但是MongoDB中这引发异常:
Traceback (most recent call last):
File "/usr/local/lib/python2.6/dist-packages/gevent/greenlet.py", line 403, in run
result = self._run(*self.args, **self.kwargs)
File "/data/www/public/app/seotools/daemon/scripts/mainconverter.py", line 129, in work
res = autoreconnect(self.db.tasks.map_reduce,m, r, query={'job_id':job_id},sort={'position':1})
File "/data/www/public/app/seotools/daemon/lib/db/mongo.py", line 95, in autoreconnect
result = func(*args,**kwargs)
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.8.1-py2.6-linux-x86_64.egg/pymongo/collection.py", line 945, in map_reduce
map=map, reduce=reduce, **kwargs)
File "/usr/local/lib/python2.6/dist-packages/pymongo-1.8.1-py2.6-linux-x86_64.egg/pymongo/database.py", line 294, in command
(command, result["errmsg"]))
OperationFailure: command SON([('mapreduce', u'tasks'), ('sort', {'position': 1}), ('query', {'job_id': ObjectId('4d0b30909c7684b60e000000')}), ('reduce', Code('function(k,values) {
data={};
for(var i=0; i<values.length; i++) {
for(attr in values[i])
data[attr]=values[i][attr];
}
return data
}', {})), ('map', Code("function() {
data = {};
res = ''
if(this.result_id) {
res={'objectid':this.result_id.toString()};
} else {
res=this.result;
}
emit(this.data, res);
}", {}))]) failed: db assertion failure
当我使用没有排序PARAM相同的查询:
res = db.tasks.map_reduce(m, r, query={'job_id':job_id})
它的工作相当精细。
哪里可以解决问题?
当你首先进行排序会发生什么? 'res = db.tasks.map_reduce(m,r,sort = {'position':pymongo.ASCENDING},query = {'job_id':job_id})'应该没关系,但是如果有的话,您可能已经找到一个错误? – 2010-12-17 18:02:00
我会试试这个,让你知道 – 2010-12-19 08:21:28
ammm ......你说得对,如果params的改变顺序有效。 – 2010-12-20 09:12:50