Spring - mongodb - aggregation - The 'cursor' option is required

Question

Executing the following aggregation pipeline:

public void getMostLikedItems () {
        UnwindOperation unwind = Aggregation.unwind("favoriteItems");
        GroupOperation group = Aggregation.group("favoriteItems").count().as("likes");
        SortOperation sort = Aggregation.sort(Sort.Direction.DESC, "likes");

        Aggregation aggregation = newAggregation(unwind, group, sort);
        DBObject result = mongoTemplate.aggregate(aggregation, "users", LikedItem.class).getRawResults();
}

throws the following exception:

com.mongodb.MongoCommandException: Command failed with error 9: 'The 'cursor' option is required, except for aggregate with the explain argument' on server localhost:27017. The full response is { "ok" : 0.0, "errmsg" : "The 'cursor' option is required, except for aggregate with the explain argument", "code" : 9, "codeName" : "FailedToParse" }

I don't understand what is meant by cursor option here. Where should this option be configured?

EDIT Here is a sample user document

{
  "_id": "5a6df13552f42a34dcca9aa6",
  "username": "user1",
  "password": "$2a$10$p0OXq5PPa41j1e4iPcGZHuWjoKJ983sieS/ovFI.cVX5Whwj21WYi",
  "favoriteItems": [
    {
      "_id": "5a0c6b2dfd3eb67969316d6d",
      "name": "item1",
      "city": "Rabat"
    },
    {
      "_id": "5a0c680afd3eb67969316d0b",
      "name": "item2",
      "city": "Rabat"
    }
  ]
}

What is your spring mongo jar version ? See if this [helps](https://stackoverflow.com/questions/47472688/spring-data-mongodb-the-cursor-option-is-required) — s7vr, Jan 28 '18 at 19:26
@Veeram my version is 3.4.3. I found the post earlier but I did not quite get the solution. Could you please help me understand it with a basic example or a link to an example? — Blank, Jan 28 '18 at 19:36

s7vr · Accepted Answer · 2018-01-29T11:03:45.303

4

From the docs.

MongoDB 3.4 deprecates the use of aggregate command without the cursor option, unless the pipeline includes the explain option. When returning aggregation results inline using the aggregate command, specify the cursor option using the default batch size cursor: {} or specify the batch size in the cursor option cursor: { batchSize: }.

You can pass batchSize with AggregationOptions in Spring Mongo 2.x version

Aggregation aggregation = newAggregation(unwind, group).withOptions(newAggregationOptions().cursorBatchSize(100).build());

With default batch size

Aggregation aggregation = newAggregation(unwind, group).withOptions(newAggregationOptions().cursor(new Document()).build());

edited Jan 29 '18 at 11:03

answered Jan 28 '18 at 20:01

s7vr

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My spring boot parent project is version 1.5.9. Can I upgrade spring data mongodb to version 2? sorry if this is outside the context of the question – Blank Jan 28 '18 at 20:12
Np. Do you see `AggregationOptions` class ? You can ` org.springframework.data spring-data-mongodb 2.0.2.RELEASE ` in your Pom dependencies to download 2.0 version. Btw I'll check what verison of spring mongo does spring boot 1.5.9 provide. – s7vr Jan 28 '18 at 20:20
3

1.5.9 boot references 1.10.9 spring mongo version which has AggregationOptions class. So you can try `Aggregation aggregation = newAggregation(unwind, group).withOptions(newAggregationOptions().cursor(new BasicDBObject());` – s7vr Jan 28 '18 at 20:46
i just tried it. the options need to be built before passing to withOptions() because this function takes AggregationOptions and not AggregationOptions.Builder. Thus, i did this `AggregationOptions options = newAggregationOptions().cursor(new BasicDBObject()).build();` then `Aggregation aggregation = newAggregation(unwind, group).withOptions(options);` then `System.out.println(mongoTemplate.aggregate(aggregation, "users", LikedItem.class).getRawResults());` but it returns `{ "cursor" : { "firstBatch" : [ ] , "id" : 0 , "ns" : "ShopDB.users"} , "ok" : 1.0}` – Blank Jan 29 '18 at 10:56
I see. You can also try `Aggregation aggregation = newAggregation(unwind, group).withOptions(newAggregationOptions().cursor(new BasicDBObject()).build());` Did you try setting batchsize ? You dont see any results do you ? – s7vr Jan 29 '18 at 11:00
No result. I think maybe new BasicDBObject() has default batchsize of zero – Blank Jan 29 '18 at 11:07
I dont think so. May be your query is not returning any results. Did you get a chance to try with setting some batch size ? Something like `Aggregation aggregation = newAggregation(unwind, group).withOptions(newAggregationOptions().cursorBatchSize(10).build());` – s7vr Jan 29 '18 at 11:23
1

Not really, after i upgraded my spring mongo jar to 2.0.3, my application throws other exceptions that i cant deal with at the moment so i rollbacked to the default one `spring-boot-starter-data-mongodb`. what i tried instead is `newAggregationOptions().cursor(new BasicDBObject("batchSize", 100)).build()` but no results still. – Blank Jan 29 '18 at 12:16
Oh sorry. Can you output `aggregation.toString()` to console and copy & paste the generated query into shell and see if it returns anything ? Add some sample document to the post and I can also try at my end. – s7vr Jan 29 '18 at 12:30
This is what aggregate generates `{ "aggregate" : "__collection__" , "pipeline" : [ { "$unwind" : "$favoriteItems"} , { "$group" : { "_id" : "$favoriteItems" , "likes" : { "$sum" : 1}}}] , "cursor" : { }}` i noticed that the collection name is not `users`. I tried it in the shell and i get 'SyntaxError: missing ; before statement @(shell):1:14' for both `__collection__ `and `users` – Blank Jan 29 '18 at 17:44
Also, I edited the post to include a sample user document. – Blank Jan 29 '18 at 17:51
That is fine. Can you try `db.users.aggregate( [ { "$unwind" : "$preferredShops"} , { "$group" : { "_id" : "$preferredShops" , "likes" : { "$sum" : 1}}}], {"cursor" : { "batchSize" : 100}} )` in shell ? **Update** works for me in shell with document you've provided. Just needed to change to `$favoriteItems` – s7vr Jan 29 '18 at 17:51
Yes the aggregate function works for me too when triggered from the shell. The issue is with its java translation – Blank Jan 29 '18 at 18:02
Indeed the cursor option is not working in `1.10.x` spring version. You can fix that by accessing the low level `DBCollection` and passing the aggregation stages with `AggregationOptions( mongdb pacakge)` – s7vr Jan 29 '18 at 18:23
Something like `DBCollection col = mongoTemplate.getCollection("users"); Cursor cursor = col.aggregate(Arrays.asList(unwind.toDBObject(Aggregation.DEFAULT_CONTEXT), group.toDBObject(Aggregation.DEFAULT_CONTEXT), sort.toDBObject(Aggregation.DEFAULT_CONTEXT)), AggregationOptions.builder().batchSize(100).build()); while(cursor.hasNext()) { DBObject dbObject = (DBObject) cursor.next(); System.out.println(dbObject); }` – s7vr Jan 29 '18 at 18:24
2

In boot 1.5 / data-mongo 1.10, `mongoTemplate.aggregate(...).getRawResults()` returns a `DBObject` which maps this structure : `{ "cursor" : { "firstBatch" : [ {"_id" : ObjectId("...")}, {"_id" : ObjectId("...")}, ], "id" : NumberLong(0), "ns" : "..." }, "ok" : 1.0, "operationTime" : ... }`. You have to walk through _cursor.firstBatch_ using `DBObject.get(...)` to get the actual query results, Spring cannot map reults from the cursor. (That's hardly readable, sorry) – gregfqt Feb 13 '19 at 14:09

Adarsh Patel · Answer 2 · 2018-08-02T09:16:59.647

'The 'cursor' option is required, except for aggregate with the explain argument'

This type of error raised in spring data when you are using incompatible versions of MongoDB and Spring-data-mongo.

Though you can get rawResults with explain, cursor arguments.

Aggregation aggregation = Aggregation.newAggregation(group).withOptions( new AggregationOptions(allowDiskUse, explain, cursor));

//try with .withOptions( new AggregationOptions(true,false,new Document()));

Passing by commented Arguments you will get result in rawResult but it will not be mapped in given outType.class.

To get mapped result you have to download right dependency of spring-data version according to your MongoDb version.

EDIT

I have used Spring version 5.0.3 and Spring-data-mongoDB version 2.0.3 It is working Fine.

score 1 · Answer 3 · answered Jan 22 '20 at 11:01

You can provide outputmode as cursor as providing a cursor is mandatory

List<DBObject> list = new ArrayList<DBObject>();
list.add(unwind.toDBObject(Aggregation.DEFAULT_CONTEXT));
list.add(group.toDBObject(Aggregation.DEFAULT_CONTEXT));
list.add(sort.toDBObject(Aggregation.DEFAULT_CONTEXT));

DBCollection col = mongoTemplate.getCollection("users");

Cursor cursor = col.aggregate(list, AggregationOptions.builder().allowDiskUse(true).outputMode(OutputMode.CURSOR).build());

List<AggregationResultVO> result = new ArrayList<AggregationResultVO>();

while(cursor.hasNext()) {
     DBObject object = cursor.next();
     result.add(new AggregationResultVO(object.get("aggregationResultId").toString()));
}

Spring - mongodb - aggregation - The 'cursor' option is required

3 Answers3

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