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Type:
Bug
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Resolution: Duplicate
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Priority:
Major - P3
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None
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Affects Version/s: 3.6.2
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Component/s: Aggregation Framework
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None
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Environment:db.version() --> 3.6.2
OS: MacOS High Sierra 10.13.1
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ALL
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STR:
1. Create new test collection
2. Insert documents from the test.json
file
3. Run the following query:db.getCollection('test').aggregate([ { "$match": { "$and": [ { "status": { "$eq": "active" } } ] } }, { "$sort": { "status": 1 } }, { "$skip": 4 }, { "$limit": 2 } ])
Expected result: the documents with ids 6 and 7 are returned as in chained query
db.getCollection('test') .find({ "$and": [ { "status": { "$eq": "active" } } ] }) .sort({ "status": 1 }) .skip(4) .limit(2)
Actual result: the documents with ids 3 and 5 are returned
STR: 1. Create new test collection 2. Insert documents from the test.json file 3. Run the following query: db.getCollection( 'test' ).aggregate([ { "$match" : { "$and" : [ { "status" : { "$eq" : "active" } } ] } }, { "$sort" : { "status" : 1 } }, { "$skip" : 4 }, { "$limit" : 2 } ]) Expected result: the documents with ids 6 and 7 are returned as in chained query db.getCollection( 'test' ) .find({ "$and" : [ { "status" : { "$eq" : "active" } } ] }) .sort({ "status" : 1 }) .skip(4) .limit(2) Actual result: the documents with ids 3 and 5 are returned
I was trying to use an aggregation pipeline in the following order:
match -> sort -> skip(4) -> limit(2)
In my case:
1. Match step returned 6 documents
2. Sort step sorts data, but they all have the same value in the sorted column
3. Skip step skips first 4 documents
4. Limit step limits the result to 2 documents.
I expected to see last 2 documents from the match result, but the query returned 2-nd and 4-th documents from the match result. If I set a limit to 3, then everything works as expected (I receive last 2 documents). The other way to get a correct result is to add an _id : 1 as the last sort column in sort step or exclude sort step at all.
If I use simple chaining like .find().sort().skip().limit() it works correct too.
- duplicates
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- Closed
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