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shardConnPoolStats (database command)

This version of the documentation is archived and no longer supported. To upgrade your 6.0 deployment, see the MongoDB 7.0 upgrade procedures.

Definition

shardConnPoolStats

Removed in MongoDB 5.0. Use connPoolStats instead.

Returns information on the pooled and cached connections in the sharded connection pool. The command also returns information on the per-thread connection cache in the connection pool.

The shardConnPoolStats command uses the following syntax:

{ shardConnPoolStats: 1 }

The sharded connection pool is specific to connections between members in a sharded cluster. The mongos instances in a cluster use the connection pool to execute client reads and writes. The mongod instances in a cluster use the pool when issuing mapReduce to query temporary collections on other shards.

When the cluster requires a connection, MongoDB pulls a connection from the sharded connection pool into the per-thread connection cache. MongoDB returns the connection to the connection pool after every operation.

Compatibility

This command is available in deployments hosted in the following environments:

MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

MongoDB Enterprise: The subscription-based, self-managed version of MongoDB
MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

Output

shardConnPoolStats.hosts

Displays connection status for each config server, replica set, and standalone instance in the cluster.

shardConnPoolStats.hosts.<host>.available: The number of connections available for this host to connect to the mongos.

shardConnPoolStats.hosts.<host>.created: The number of connections the host has ever created to connect to the mongos.

shardConnPoolStats.replicaSets

Displays information specific to replica sets.

shardConnPoolStats.replicaSets.<name>.host

Holds an array of documents that report on each replica set member. These values derive from the replica set status values.

shardConnPoolStats.replicaSets.<name>.host[n].addr: The host address in the format [hostname]:[port].

shardConnPoolStats.replicaSets.<name>.host[n].ok: This field is for internal use. Reports false when the mongos either cannot connect to instance or received a connection exception or error.

shardConnPoolStats.replicaSets.<name>.host[n].ismaster: The host is the replica set's primary if this is true.

shardConnPoolStats.replicaSets.<name>.host[n].hidden: The host is a hidden member of the replica set if this is true.

shardConnPoolStats.replicaSets.<name>.host[n].secondary

The host is a hidden member of the replica set if this is true.

The host is a secondary member of the replica set if this is true.

shardConnPoolStats.replicaSets.<name>.host[n].pingTimeMillis: The latency, in milliseconds, from the mongos to this member.

shardConnPoolStats.replicaSets.<name>.host[n].tags

A tags document contains user-defined tag field and value pairs for the replica set member.

{ "<tag1>": "<string1>", "<tag2>": "<string2>",... }

For read operations, you can specify a tag set in the read preference to direct the operations to replica set member(s) with the specified tag(s).
For write operations, you can create a customize write concern using settings.getLastErrorModes and settings.getLastErrorDefaults.

For more information, see Configure Replica Set Tag Sets.

Tip

members[n].tags

shardConnPoolStats.createdByType

The number connections in the cluster's connection pool.

shardConnPoolStats.createdByType.master: The number of connections to a shard.

shardConnPoolStats.createdByType.set: The number of connections to a replica set.

shardConnPoolStats.createdByType.sync: The number of connections to the config database.

shardConnPoolStats.totalAvailable: The number of connections available from the mongos to the config servers, replica sets, and standalone mongod instances in the cluster.

shardConnPoolStats.totalCreated: The number of connections the mongos has ever created to other members of the cluster.

shardConnPoolStats.threads

Displays information on the per-thread connection cache.

shardConnPoolStats.threads.hosts

Displays each incoming client connection. For a mongos, this array field displays one document per incoming client thread. For a mongod, the array displays one entry per incoming sharded mapReduce client thread.

shardConnPoolStats.threads.hosts.host: The host using the connection. The host can be a config server, replica set, or standalone instance.

shardConnPoolStats.threads.hosts.created: The number of times the host pulled a connection from the pool.

shardConnPoolStats.threads.hosts.avail: The thread's availability.

shardConnPoolStats.threads.seenNS: The namespaces used on this connection thus far.

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