$group after $lookup is taking way too long - mongodb

Question

I have following mongo collection:
{
"_id" : "22pTvYLd7azAAPL5T",
"plate" : "ABC-123",
"company": "AMZ",
"_portfolioType" : "account"
},
{
"_id" : "22pTvYLd7azAAPL5T",
"plate" : "ABC-123",
"_portfolioType" : "sale",
"price": 87.3
},
{
"_id" : "22pTvYLd7azAAPL5T",
"plate" : "ABC-123",
"_portfolioType" : "sale",
"price": 88.9
}
And I am trying to aggregate all documents which have same value in plate field. Below is the query I have written so far:
db.getCollection('temp').aggregate([
{
$lookup: {
from: 'temp',
let: { 'p': '$plate', 't': '$_portfolioType' },
pipeline: [{
'$match': {
'_portfolioType': 'sale',
'$expr': { '$and': [
{ '$eq': [ '$plate', '$$p' ] },
{ '$eq': [ '$$t', 'account' ] }
]}
}
}],
as: 'revenues'
},
},
{
$project: {
plate: 1,
company: 1,
totalTrades: { $arrayElemAt: ['$revenues', 0] },
},
},
{
$addFields: {
revenue: { $add: [{ $multiply: ['$totalTrades.price', 100] }, 99] },
},
},
{
$group: {
_id: '$company',
revenue: { $sum: '$revenue' },
}
}
])
Query works fine if I remove $group stage, however, as soon as I add $group stage mongo starts an infinite processing. I tried adding $match as the first stage so to limit number of documents to process but without any luck. E.g:
{
$match: { $or: [{ _portfolioType: 'account' }, { _portfolioType: 'sale' }] }
},
I also tried using { explain: true } but it doesn't return anything helpful.

Answer 1

As Neil Lunn noticed, you very likely don't need the lookup to reach your "end goal", which is still quite vague.
Please read comments and adjust as needed:
db.temp.aggregate([
{$group:{
// Get unique plates
_id: "$plate",
// Not clear what you expect if there are documents with
// different company, and the same plate.
// Assuming "it never happens"
// You may need to $cond it here with {$eq: ["$_portfolioType", "account"]}
// but you never voiced it.
company: {$first:"$company"},
// Not exactly all documents with _portfolioType: sale,
// but rather price from all documents for this plate.
// Assuming price field is available only in documents
// with "_portfolioType" : "sale". Otherwise add a $cond here.
// If you really need "all documents", push $$ROOT instead.
prices: {$push: "$price"}
}},
{$project: {
company: 1,
// Apply your math here, or on the previous stage
// to calculate revenue per plate
revenue: "$prices"
}}
{$group: {
// Get document for each "company"
_id: "$company",
// Revenue associated with plate
revenuePerPlate: {$push: {"k":"$_id", "v":"$revenue"}}
}},
{$project:{
_id: 0,
company: "$_id",
// Count of unique plate
platesCnt: {$size: "$revenuePerPlate"},
// arrayToObject if you wish plate names as properties
revenuePerPlate: {$arrayToObject: "$revenuePerPlate"}
}}
])