Time Complexity of $addToset vs $push when element does not exist in the Array

Question

Given: Connection is Safe=True so Update\'s return will contain update information.

Say I have a documents that look like:

[{\'a\': [1]}, {\'a\': [2]}, {         


        

Answer 1

Looks like $addToSet is doing the same thing as your command: $push with a $ne check. Both would be O(N)

https://github.com/mongodb/mongo/blob/master/src/mongo/db/ops/update_internal.cpp

if speed is really important then why not use a hash:

instead of:

{'$addToSet': {'a':1}}
{'$addToSet': {'a':10}}

use:

{$set: {'a.1': 1}
{$set: {'a.10': 1}