Best match Mongodb in complex objects - mongodb

Question

I have a database with about 50k records about candidates like the example bellow:
[
{
"_id":{
"$oid":"5744eff20ca7832b5c7452321"
},
"name":"Candidate 1",
"characteristics":[
{
"name":"personal skills",
"info":[
"Great speaker",
"Very friendly",
"Born to be a leader"
]
},
{
"name":"education background",
"info":[
"Studied Mechanical Engineering",
"Best of his class 2001"
]
}
]
},
... thousands more objects with same structure
]
And given some personal skills I would like to search the best matches for that input:
Example of input:
["speaker", "leader"]
Expected output:
list of candidates (whole object) descenting from the best match.
I basically need to search only the field "personal skills".
What could be a good approach for this problem using MongoDB? Or is there another database that fits better this problem?

Answer 1

The below query using regex brings us the matching records of speaker and leader.
db.collection_name.find(
{ $and :
[
{"characteristics.info": /.*speaker.*/},
{"characteristics.info": /.*leader.*/}
]
}
)
To have a better performance we can have a Text Index as shown below, but please note that there is only one Text Index allowed per collection
db.collection_name.createIndex({"characteristics":"text"});
After our Text Index has been created we can see that it is used in our search
Using explain to view the use of Text Index
db.collection_name.find({ $and: [{"characteristics.info": /.*speaker.*/}, {"characteristics.info": /.*leader.*/}]}).explain()
Mongo shell output with query plan explained
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "test.a",
"indexFilterSet" : false,
"parsedQuery" : {
"$and" : [
{
"characteristics.info" : {
"$regex" : ".*speaker.*"
}
},
{
"characteristics.info" : {
"$regex" : ".*leader.*"
}
}
]
},
"winningPlan" : {
"stage" : "COLLSCAN",
"filter" : {
"$and" : [
{
"characteristics.info" : {
"$regex" : ".*speaker.*"
}
},
{
"characteristics.info" : {
"$regex" : ".*leader.*"
}
}
]
},
"direction" : "forward"
},
"rejectedPlans" : [ ]
},
"serverInfo" : {
"host" : "PC369236",
"port" : 27017,
"version" : "3.6.1",
"gitVersion" : "025d4f4fe61efd1fb6f0005be20cb45a004093d1"
},
"ok" : 1
}