how to see open connections in mongodb [duplicate] - mongodb

Question

My program requires a large number of connections to be open (Mongo). I get the error :
Too many connections open, can't open anymore
after 819 connections. I already know we can increase this limit. But that's not what I have in mind. I'm thinking of closing the MongoClient object, and then creating a new one again after 800 connections.
My thinking is that with a new mongoClient object all the connections will be closed and when I start/create it again, the connections will be opened again until 800.
Thus not giving the error. (Let me know if this approach is totally wrong/ won't give the required results.)
For this I need to know the number of connections opened ATM. Is there any way to get this information using java?

Answer 1

You can get connection information by using the db.serverStatus() command. It has a connections subdocument which contains the total/available connections information.
For more information :
Documentation of server status
Details of connections block

Answer 2

Check the number of MongoDB connections using MongoDB Scala driver:
Create a MongoDB client:
import org.mongodb.scala._
import scala.collection.JavaConverters._
import scala.concurrent.Await
import scala.concurrent.duration._
import scala.util.{Failure, Success, Try}
// To directly connect to the default server localhost on port 27017
val mongodbClient: MongoClient = MongoClient()
// Use a Connection String
val mongodbClient: MongoClient = MongoClient("mongodb://localhost")
// or provide custom MongoClientSettings
val settings: MongoClientSettings = MongoClientSettings.builder()
.applyToClusterSettings(b => b.hosts(List(new ServerAddress("localhost")).asJava).
.build()
val mongodbClient: MongoClient = MongoClient(settings)
Call getNoOfMongodbConnection by passing mongodbClient:
val result = getNoOfMongodbConnection(mongodbClient)
Method to get the number of connections(current, available and total)
def getNoOfMongodbConnection(mongodbClient: MongoClient) = {
val adminDatabase = mongodbClient.getDatabase("admin")
val serverStatus = adminDatabase.runCommand(Document("serverStatus" -> 1)).toFuture()
Try {
Await.result(serverStatus, 10 seconds)
} match {
case Success(x) => {
val connection = x.get("connections")
logger.info("Number of mongodb connection:--> " + connection)
connection
}
case Failure(ex) => {
logger.error("Got error while getting the number of Mongodb connection:---> " + ex.printStackTrace())
None
}
}
}