How to use $text search inside $lookup pipeline - database

Question

I have the next collection for exaple:
// vehicles collection
[
{
"_id": 321,
manufactor: SOME-OBJECT-ID
},
{
"_id": 123,
manufactor: ANOTHER-OBJECT-ID
},
]
And I have a collection named tables:
// tables collection
[
{
"_id": SOME-OBJECT-ID,
title: "Skoda"
},
{
"_id": ANOTHER-OBJECT-ID,
title: "Mercedes"
},
]
As you can see, the vehicles collection's documents are pulling data from the
tables's collection ducments - the first document in the vehicles collection has a manufactor
id which is getting pulled from the tables collection and named Skoda.
That is great.
When I am querying the DB using aggregate I can able to easily pull the remote data from the remote collections
respectively - without any problem.
I can also easily make rules and limitations like $project, $sort, $skip, $limit and others.
But I want to display to the user only those vehicles that are manufcatord by Mercedes.
Since Mercedes is not mentioned in the vehicles collection, but only its ID, the $text $search would not
return with the right results.
This is the aggregate pipeline that I provide:
[
{
$match: {
$text: {
$search: "Mercedes"
}
}
},
{
$lookup: {
from: "tables",
let: {
manufactor: "$manufactor"
},
pipeline: [
{
$match: {
$expr: {
$eq: [
"$_id", "$$manufactor"
]
}
}
},
{
$project: {
title: 1
}
}
],
as: "manufactor"
},
},
{
$unwind: "$manufactor"
},
{
$lookup: {
from: "tables",
let: {
model: "$model"
},
pipeline: [
{
$match: {
$expr: {
$eq: [
"$_id", "$$model"
]
}
}
},
{
$project: {
title: 1
}
}
],
as: "model"
},
},
{
$unwind: "$model"
},
{
$lookup: {
from: "users",
let: {
joined_by: "$_joined_by"
},
pipeline: [
{
$match: {
$expr: {
$eq: [
"$_id", "$$joined_by"
]
}
}
},
{
$project: {
personal_info: 1
}
}
],
as: "joined_by"
},
},
{
$unwind: "$joined_by"
}
]
As you can see I am using the $text and $search $match at the first stage in the pipleline - otherwise
MongoDB will throw an error.
But this $text $search object searhed only in the origin collection - the vehicles collection.
Is there a way to tell MongoDB to search in the remote collection with the $text and $search method
and then put in the aggregate only results that are matching both?
UPDATE
When I am doing this instead:
{
$lookup: {
from: "tables",
pipeline: [
{
$match: {
$text: {
$search: "Mercedes"
}
}
},
{
$project: {
title: 1
}
}
],
as: "manufactor"
},
},
This is what I receive:
MongoError: pipeline requires text score metadata, but there is no text score available

Answer 1

if you are using one of the affected versions in this thread, you need to update your mongodb server.
As you can see the issue was fixed in version 4.1.8