CODEWITHSUNDEEP
mongodbmongoose
NoobSter
NoobSter

Reputation: 1160

How does mongoDB order values when sorting, if the values are the same?

for instance, if i'm sorting a collection by val in : 

 `[{id: 1, val: 1}, {id: 2, val: 2} , {id: 3, val: 3}, {id: 4, val: 2}]

, etc.. How does it determine which val of 2 comes first?

Upvotes: 2

Views: 864

Answers (1)

Adam Harrison
Adam Harrison

Reputation: 3421

If the query is reading the values sorted from an index, the ordering will most likely be inherited from how the documents are stored in the index (https://docs.mongodb.com/manual/reference/method/cursor.sort/#sort-and-index-use).

For example, if the query is reading the results pre-sorted from the index { "val" : 1, "val2" : 1 }, then the results would likely be sorted by the field "val2".

If documents are being sorted in memory, then results are likely not guaranteed to have a specific order beyond what is specified in the sort clause.

Upvotes: 2

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