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Connection Pool Statistics Reference

Connection Pool Statistics Reference¶

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Synopsis
Output

Synopsis¶

mongos instances maintain a pool of connections for interacting with constituent members of the sharded cluster. Additionally, mongod instances maintain connection with other shards in the cluster for migrations. The connPoolStats command returns statistics regarding these connections between the mongos and mongod instances or between the mongod instances in a shard cluster.

Note

connPoolStats only returns meaningful results for mongos instances and for mongod instances in sharded clusters.

Output¶

connPoolStats.hosts¶

The sub-documents of the hosts document report connections between the mongos or mongod instance and each component mongod of the sharded cluster.

connPoolStats.hosts.[host].available¶: available reports the total number of connections that the mongos or mongod could use to connect to this mongod.

connPoolStats.hosts.[host].created¶: created reports the number of connections that this mongos or mongod has ever created for this host.

connPoolStats.replicaSets¶

replicaSets is a document that contains replica set information for the sharded cluster.

connPoolStats.replicaSets.shard¶: The shard document reports on each shard within the sharded cluster

connPoolStats.replicaSets.[shard].host¶

The host field holds an array of document that reports on each host within the shard in the replica set.

These values derive from the replica set status values.

connPoolStats.replicaSets.[shard].host[n].addr¶: addr reports the address for the host in the sharded cluster in the format of “[hostname]:[port]”.

connPoolStats.replicaSets.[shard].host[n].ok¶

ok reports false when:

the mongos or mongod cannot connect to instance.
the mongos or mongod received a connection exception or error.

This field is for internal use.

connPoolStats.replicaSets.[shard].host[n].ismaster¶: ismaster reports true if this host is the primary member of the replica set.

connPoolStats.replicaSets.[shard].host[n].hidden¶: hidden reports true if this host is a hidden member of the replica set.

connPoolStats.replicaSets.[shard].host[n].secondary¶: secondary reports true if this host is a secondary member of the replica set.

connPoolStats.replicaSets.[shard].host[n].pingTimeMillis¶: pingTimeMillis reports the ping time in milliseconds from the mongos or mongod to this host.

connPoolStats.replicaSets.[shard].host[n].tags¶: New in version 2.2.

tags reports the tags, if this member of the set has tags configured.

connPoolStats.replicaSets.[shard].master¶: master reports the ordinal identifier of the host in the host array that is the primary of the replica set.

connPoolStats.replicaSets.[shard].nextSlave¶: Deprecated since version 2.2.

nextSlave reports the secondary member that the mongos will use to service the next request for this replica set.

connPoolStats.createdByType¶

createdByType document reports the number of each type of connection that mongos or mongod has created in all connection pools.

mongos connect to mongod instances using one of three types of connections. The following sub-document reports the total number of connections by type.

connPoolStats.createdByType.master¶: master reports the total number of connections to the primary member in each cluster.

connPoolStats.createdByType.set¶: set reports the total number of connections to a replica set member.

connPoolStats.createdByType.sync¶: sync reports the total number of config database connections.

connPoolStats.totalAvailable¶: totalAvailable reports the running total of connections from the mongos or mongod to all mongod instances in the sharded cluster available for use.

connPoolStats.totalCreated¶: totalCreated reports the total number of connections ever created from the mongos or mongod to all mongod instances in the sharded cluster.

connPoolStats.numDBClientConnection¶: numDBClientConnection reports the total number of connections from the mongos or mongod to all of the mongod instances in the sharded cluster.

connPoolStats.numAScopedConnection¶: numAScopedConnection reports the number of exception safe connections created from mongos or mongod to all mongod in the sharded cluster. The mongos or mongod releases these connections after receiving a socket exception from the mongod.

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