Mongodb query takes too long if no matches found - database

Question

I have a posts collection like bellow :
{
"_id" : ObjectId("5ad249121c76fb096c0081e6"),
"slug" : "5ad2491261324",
"title" : "title",
"content" : "content here",
"tags" : [
"tag1",
"tag2"
],
"status" : 1,
"created_at" : ISODate("2018-04-12T07:23:07.000Z"),
"user_id" : ObjectId("5ad249111c76fb096c007dfd"),
"url_id" : ObjectId("5ad249121c76fb096c0081e7"),
"updated_at" : ISODate("2018-04-14T18:31:46.000Z"),
"images" : [
{
"extension" : "jpg",
"path" : "/medias/tests/4.jpg",
"thumbnail" : "/medias/tests/4-th.jpg",
"updated_at" : ISODate("2018-04-14T18:31:46.000Z"),
"created_at" : ISODate("2018-04-14T18:31:46.000Z"),
"_id" : ObjectId("5ad249121c76fb096c0081e8")
}
]
}
The collection has text index on title.
When i execute bellow query :
db.getCollection('posts').find({title: /test/})
If there is at least one matches, the query executes very fast. But when it has not matches, takes too long to execute.
Why this happening?
Edit
I have 100m record in this collection.

Answer 1

MongoDB facilitates creating text indexes on fields to search text contained into fields belonging to collection of MongoDB Database
According to description as mentioned into above question collection has a text index on title field.
Hence to search a string value into title field please try executing following find operation into MongoDB shell.
db.getCollection('posts').find({
$text: {
$search: 'test'
})
According to documentation of MongoDB
$text performs a text search on the content of the fields indexed with
a text index.