Hello there community.
I am a student and I have now worked in multiple projects with mongodb and I focused on aggregations since requests became more and more complicated.
But there has been one roadblock that leads to issues over, over, and over again.
I want to make as few db calls as possible, meaning I want a single aggregation to get all the data I want.
We can merge multiple aggregations with $facet, but since this has an actual bytelimit, it doesn’t help in the following example:
I want to retrieve data, but also statistics and counts over lookups and whatsoever.
This leads to me doing $group, get the $size of an array, then $unwind multiple times to flatten some nested arrays, and finally $facet to get another count and data.
What I am trying to say here, is that it would make some aggregations so much easier, if I could instead of a facet, could also store a variable parallel to my aggregations ignored in the stages and only then used when I need it at the end for example.
In short the issue is: I perform actions like $group, then get a calculated variabel or count and $unwinding it all, do a lot more actions on a potentially facet-bytelimit exceeding amount of data forcing me to add the variable to all documents in all stages.
I would love to be able to have an alternative to the $facet, with an even smaller byte limit of that matter, but something where I have a stage with an aggregation that doesn’t change the above stage, but adds a parallel value which I can retrieve in forexample a $project.
Does something like this already exist or could this be implemented in the future?