On Mar 8, 2010, at 12:28 AM, Gregory Tappero wrote:
> Thanks,
>
> I got the wanted result with
> http://friendpaste.com/6sYxT4cNJ9IjpWiW9qgCut
>
> benoitc came to my rescue.
>
The will be a problem with large databases. When the # of unique users is large, the group=false
query would return a very large object with all the users names in it. Except it won't because
it will raise a reduce_overflow_error.
Your problem is interesting. You might learn from reading this paper:
http://labs.google.com/papers/sawzall.html
It gives a survey of the available algorithms which can work in constant space even over large
databases.
Chris
> Greg
>
>
>
>
> On Mon, Mar 8, 2010 at 9:07 AM, Paweł Stawicki <pawelstawicki@gmail.com> wrote:
>> Hmm... I'm just thinking now, don't know if it works, but maybe try
>> something like this:
>> If you can get number of documents per day per username, first try to make
>> this number always one if keys is [date, username]:
>> Reduce:
>> if (keys.length == 2) {
>> return 1;
>> } else if (keys.length == 1) { //date only, return number of usernames
>> return values.length();
>> }
>>
>> The risk is that some usernames will count twice, but maybe try it.
>>
>> Best regards
>> --
>> Paweł Stawicki
>> http://pawelstawicki.blogspot.com
>> http://szczecin.jug.pl
>>
>>
>>
>> On Mon, Mar 8, 2010 at 08:03, Gregory Tappero <coulix@gmail.com> wrote:
>>
>>> My number of keys is 4, year month day userame so returning the bbr of
>>> keys in reduce does not seem to give me the output i am looking for.
>>> Unless i misunderstood something.
>>>
>>> Thank you for helping,
>>>
>>> Greg
>>>
>>> On Mon, Mar 8, 2010 at 12:28 AM, Randall Leeds <randall.leeds@gmail.com>
>>> wrote:
>>>> I'm not an expert on this, but I think you need to create your own
>>>> reduce function and output the number of keys rather than the sum of
>>>> the values.
>>>>
>>>> On Sun, Mar 7, 2010 at 15:15, Gregory Tappero <coulix@gmail.com> wrote:
>>>>> Thank you Pawel,
>>>>>
>>>>> If i try to follow your way it gives me the count of docs in a given
>>>>> day for each username, what i would like is the count of unique
>>>>> usernames for a given day.
>>>>>
>>>>> function(doc) {
>>>>>
>>>>> if (doc.doc_type=="EdoPing" && doc.em_type==0) {
>>>>> date = new Date().setRFC3339(doc.created_at);
>>>>> emit([date.getFullYear(), parseInt(date.getMonth())+1,
>>>>> date.getDate(), doc.em_uname] , 1);
>>>>>
>>>>> }
>>>>> }
>>>>>
>>>>> Reduce:
>>>>> _count
>>>>>
>>>>> =================
>>>>> I get:
>>>>>
>>>>> [2010, 3, 3, "student1"] 5
>>>>> [2010, 3, 4, "student1"] 18
>>>>> [2010, 3, 5, "eong"] 77
>>>>> [2010, 3, 6, "bkante"] 71
>>>>> [2010, 3, 6, "jfrancillette"] 72
>>>>> [2010, 3, 6, "mlouviers"] 12
>>>>> [2010, 3, 7, "student1"] 4
>>>>>
>>>>> I would like to extract the following
>>>>>
>>>>> [2010, 3, 3] 1
>>>>> [2010, 3, 4] 1
>>>>> [2010, 3, 5] 1
>>>>> [2010, 3, 6] 3
>>>>> [2010, 3, 7] 1
>>>>>
>>>>>
>>>>> if i do a group_level=3 it sum the values.
>>>>>
>>>>> {"key":[2010,3,3],"value":5},
>>>>> {"key":[2010,3,4],"value":18},
>>>>> {"key":[2010,3,5],"value":77},
>>>>> {"key":[2010,3,6],"value":155},
>>>>> {"key":[2010,3,7],"value":4}
>>>>>
>>>>> How can i count the unique username emitter per day ?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Sun, Mar 7, 2010 at 10:02 PM, Paweł Stawicki <
>>> pawelstawicki@gmail.com> wrote:
>>>>>> Just emit all documents with em_type = 0 in map function, with [date,
>>>>>> em_uname] as key. Then count in reduce.
>>>>>>
>>>>>> Map:
>>>>>> function(doc) {
>>>>>> if (doc.em_type = 0) {
>>>>>> //If you only want to count, you can emit anything (e.g. 1) instead
>>> of
>>>>>> doc here.
>>>>>> emit([date, em_uname], doc);
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> Reduce:
>>>>>> function(keys, values, rereduce) {
>>>>>> if (!rereduce) {
>>>>>> return count_of_values;
>>>>>> } else {
>>>>>> return sum_of_values;
>>>>>> }
>>>>>>
>>>>>> //If you return 1 from emit instead of doc, then count_of_values
==
>>>>>> sum_of_values
>>>>>> }
>>>>>>
>>>>>> Then you can handle everything by grouping:
>>>>>> http://yourserver:5984/yourdb/_view/yourview?group_level=2
>>>>>> or group=true
>>>>>>
>>>>>> Regards
>>>>>> --
>>>>>> Paweł Stawicki
>>>>>> http://pawelstawicki.blogspot.com
>>>>>> http://szczecin.jug.pl
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sat, Mar 6, 2010 at 16:26, Gregory Tappero <coulix@gmail.com>
>>> wrote:
>>>>>>
>>>>>>> Hello everyone,
>>>>>>>
>>>>>>> I have the following EdoPing 's type of documents
>>>>>>>
>>>>>>> {
>>>>>>> "_id": "22add509c1e7bc286832edc5bfe99ce5",
>>>>>>> "_rev": "1-49663ab8778f445e481143120d0d7086",
>>>>>>> "doc_type": "EdoPing",
>>>>>>> "em_uname": "student1",
>>>>>>> "em_gid": 1,
>>>>>>> "created_at": "2010-03-03T14:18:19Z",
>>>>>>> "em_ip": "92.154.70.148",
>>>>>>> "em_type": 0,
>>>>>>> "room_url": "z2fudcvcrfa3reaydatre",
>>>>>>> "room_users": [
>>>>>>> "tutorsbox"
>>>>>>> ]
>>>>>>> }
>>>>>>>
>>>>>>> i would like to count all unique em_uname of em_type 0 on a given
day
>>> date.
>>>>>>>
>>>>>>> For now i used this map/reduce
>>>>>>> http://friendpaste.com/5xUUQ26bbl9d5KRB8eojwe
>>>>>>>
>>>>>>> Date.prototype.setRFC3339 = function(dString){
>>>>>>> var regexp =
>>>>>>>
>>>>>>>
>>> /(\d\d\d\d)(-)?(\d\d)(-)?(\d\d)(T)?(\d\d)(:)?(\d\d)(:)?(\d\d)(\.\d+)?(Z|([+-])(\d\d)(:)?(\d\d))/;
>>>>>>>
>>>>>>> if (dString.toString().match(new RegExp(regexp))) {
>>>>>>> var d = dString.match(new RegExp(regexp));
>>>>>>> var offset = 0;
>>>>>>>
>>>>>>> this.setUTCDate(1);
>>>>>>> this.setUTCFullYear(parseInt(d[1],10));
>>>>>>> this.setUTCMonth(parseInt(d[3],10) - 1);
>>>>>>> this.setUTCDate(parseInt(d[5],10));
>>>>>>> this.setUTCHours(parseInt(d[7],10));
>>>>>>> this.setUTCMinutes(parseInt(d[9],10));
>>>>>>> this.setUTCSeconds(parseInt(d[11],10));
>>>>>>> if (d[12])
>>>>>>> this.setUTCMilliseconds(parseFloat(d[12]) * 1000);
>>>>>>> else
>>>>>>> this.setUTCMilliseconds(0);
>>>>>>> if (d[13] != 'Z') {
>>>>>>> offset = (d[15] * 60) + parseInt(d[17],10);
>>>>>>> offset *= ((d[14] == '-') ? -1 : 1);
>>>>>>> this.setTime(this.getTime() - offset * 60 * 1000);
>>>>>>> }
>>>>>>> } else {
>>>>>>> this.setTime(Date.parse(dString));
>>>>>>> }
>>>>>>> return this;
>>>>>>> };
>>>>>>>
>>>>>>> var seenKeys = new Array();
>>>>>>>
>>>>>>> function(doc) {
>>>>>>>
>>>>>>>
>>>>>>> if (doc.doc_type=="EdoPing" && doc.em_type==0) {
>>>>>>> date = new Date().setRFC3339(doc.created_at);
>>>>>>> var key = doc.em_uname +
>>> String(doc.created_at).substring(0,10);
>>>>>>> if (seenKeys[key] == undefined ) {
>>>>>>> seenKeys[key] = 1;
>>>>>>> emit([date.getFullYear(), parseInt(date.getMonth())+1,
>>>>>>> date.getDate() ] , 1);
>>>>>>> }
>>>>>>> }
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> It works when saved for this first time but as soon as new EdoPings
>>>>>>> get added it starts emitting rows it has already seen ! (same
key)
>>>>>>> creating faulty count results.
>>>>>>>
>>>>>>> Is it ok to have seenKeys outside of the doc function() ?
>>>>>>> What other way could i use to get the same results ?
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Greg
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Greg Tappero
>>>>> CTO co founder Edoboard
>>>>> http://www.edoboard.com
>>>>> +33 0645764425
>>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> Greg Tappero
>>> CTO co founder Edoboard
>>> http://www.edoboard.com
>>> +33 0645764425
>>>
>>
>
>
>
> --
> Greg Tappero
> CTO co founder Edoboard
> http://www.edoboard.com
> +33 0645764425
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