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How to limit the connections per host in MongoDB?
Reduce the connection pool size in the clients. MongoDB (as at 2.6) doesn’t have an option to limit the connections per client. Normally client limits would be imposed via the driver (i.e. setting the connection pool size). For example, in the Java driver the MongoClient default maximum pool size is 100.
How many MongoDB nodes can Atlas allocate to?
The number of mongos routers is equal to the number of replica set nodes across all shards. Your read preference also contributes to the total number of connections Atlas can allocate for a given query. Your M2 cluster has three nodes with a 500 connection limit per node. Atlas reserves 10 connections per node.
Is it possible to pool connections in MongoDB?
One notable exception is setups where your app spawns a new process for each request, such as CGI and some configurations of PHP. Whatever driver you’re using, you’ll have to find out how they handle connections and if they pool or not.
Is it possible to scale MongoDB to 20K concurrent users?
You don’t want to open a new database connection each time a new user connects. I don’t know if you’ll be able to scale to 20k+ concurrent users easily, since MongoDB uses a new thread for each new connection.
What is new in pymongo version 2.3?
New in version 2.3. The maximum number of sockets the pool will open concurrently. When the pool has reached max_pool_size, operations block waiting for a socket to be returned to the pool. If waitQueueTimeoutMS is set, a blocked operation will raise ConnectionFailure after a timeout.
What happens when a connection fails in pymongo?
The resultant connection object has connection-pooling built in. It also performs auto-reconnection when necessary. If an operation fails because of a connection error, ConnectionFailure is raised. If auto-reconnection will be performed, AutoReconnect will be raised.
Can a mongoclient connect to multiple standalone servers?
In PyMongo 2.x, MongoClient accepted a list of standalone MongoDB servers and used the first it could connect to: A list of multiple standalones is no longer supported; if multiple servers are listed they must be members of the same replica set, or mongoses in the same sharded cluster.