serverStatus

Definition

serverStatus: The serverStatus command returns a document that provides an overview of the database's state. Monitoring applications can run this command at a regular interval to collect statistics about the instance.

Syntax

The command has the following syntax:

db.runCommand(
   {
     serverStatus: 1
   }
)

The value (i.e. 1 above) does not affect the operation of the command. The db.serverStatus() command returns a large amount of data. To return a specific object or field from the output append the object or field name to the command.

For example:

db.runCommand({ serverStatus: 1}).metrics
db.runCommand({ serverStatus: 1}).metrics.commands
db.runCommand({ serverStatus: 1}).metrics.commands.update

mongosh provides the db.serverStatus() wrapper for the serverStatus command.

Tip

Behavior

By default, serverStatus excludes in its output:

some content in the repl document.
mirroredReads document. (Available starting in version 4.4)

To include fields that are excluded by default, specify the top-level field and set it to 1 in the command. To exclude fields that are included by default, specify the field and set to 0. You can specify either top-level or embedded fields.

For example, the following operation excludes the repl, metrics and locks information in the output.

db.runCommand( { serverStatus: 1, repl: 0, metrics: 0, locks: 0 } )

For example, the following operation excludes the embedded histogram field in the output.

db.runCommand( { serverStatus: 1, metrics: { query: { multiPlanner: { histograms: false } } } } )

The following example includes all repl information in the output:

db.runCommand( { serverStatus: 1,  repl: 1 } )

Initialization

The statistics reported by serverStatus are reset when the mongod server is restarted.

This command will always return a value, even on a fresh database. The related command db.serverStatus() does not always return a value unless a counter has started to increment for a particular metric.

After you run an update query, db.serverStatus() and db.runCommand({ serverStatus: 1}) both return the same values.

{
   "arrayFilters" : NumberLong(0),
   "failed" : NumberLong(0),
   "pipeline" : NumberLong(0),
   "total" : NumberLong(1)
}

Include `mirroredReads`

By default, the mirroredReads information (available starting in version 4.4) is not included in the output. To return mirroredReads information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, mirroredReads: 1 } )

Include `latchAnalysis`

By default, the latchAnalysis information (available starting in version 4.4) is not included in the output. To return latchAnalysis information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, latchAnalysis: 1 } )

Change `tcmalloc` Verbosity

By default, tcmalloc information is included in the output. This section provides memory allocation statistics for your database. To change the verbosity of the tcmalloc section, specify an integer between 0 and 2 (inclusive):

db.runCommand( { serverStatus: 1, tcmalloc: <int> } )

The command has the following behavior:

By default, tcmalloc is set to 1.
Passing a larger integer value increases the verbosity.
Passing 0 or false omits the tcmalloc section from the output.
Passing any other input results in the default setting.

For more information about how MongoDB allocates memory, see TCMalloc.

Output

Note

The output fields vary depending on the version of MongoDB, underlying operating system platform, the storage engine, and the kind of node, including mongos, mongod or replica set member.

For the serverStatus output specific to the version of your MongoDB, refer to the appropriate version of the MongoDB Manual.

asserts

"asserts" : {
   "regular" : <num>,
   "warning" : <num>,
   "msg" : <num>,
   "user" : <num>,
   "rollovers" : <num>
},

asserts: A document that reports on the number of assertions raised since the MongoDB process started. While assert errors are typically uncommon, if there are non-zero values for the asserts, you should examine the log file for more information. In many cases, these errors are trivial, but are worth investigating.

asserts.regular: The number of regular assertions raised since the MongoDB process started. Examine the log file for more information about these messages.

asserts.warning: This field always returns zero 0.

asserts.msg: The number of message assertions raised since the MongoDB process started. Examine the log file for more information about these messages.

asserts.user: The number of "user asserts" that have occurred since the last time the MongoDB process started. These are errors that user may generate, such as out of disk space or duplicate key. You can prevent these assertions by fixing a problem with your application or deployment. Examine the MongoDB log for more information.

asserts.rollovers: The number of times that the assert counters have rolled over since the last time the MongoDB process started. The counters will roll over to zero after 2 ³⁰ assertions. Use this value to provide context to the other values in the asserts data structure.

bucketCatalog

"bucketCatalog" : {
    "numBuckets" : <num>,
    "numOpenBuckets" : <num>,
    "numIdleBuckets" : <num>,
    "memoryUsage" : <num>
 }

New in version 5.0.

A document that reports metrics related to the internal storage of time series collections.

The bucketCatalog returns the following metrics:

Metric	Description
`numBuckets`	The number of buckets that store time series data internally.
`numOpenBuckets`	The number of active, uncommitted writes to buckets.
`numIdleBuckets`	The number of buckets that are not full and can store incoming time series data.
`memoryUsage`	The number of bytes used by internal bucketing data structures.

New in version 5.0.

connections

"connections" : {
   "current" : <num>,
   "available" : <num>,
   "totalCreated" : <num>,
   "active" : <num>,
   "threaded" : <num>,
   "exhaustIsMaster" : <num>,
   "exhaustHello" : <num>,
   "awaitingTopologyChanges" : <num>,
   "loadBalanced" : <num>
},

connections: A document that reports on the status of the connections. Use these values to assess the current load and capacity requirements of the server.

connections.current

The number of incoming connections from clients to the database server. This number includes the current shell session. Consider the value of connections.available to add more context to this datum.

The value will include all incoming connections including any shell connections or connections from other servers, such as replica set members or mongos instances.

connections.available: The number of unused incoming connections available. Consider this value in combination with the value of connections.current to understand the connection load on the database, and the UNIX ulimit Settings document for more information about system thresholds on available connections.

connections.totalCreated: Count of all incoming connections created to the server. This number includes connections that have since closed.

connections.active: The number of active client connections to the server. Active client connections refers to client connections that currently have operations in progress.

connections.threaded: The number of incoming connections from clients that are assigned to threads that service client requests.
New in version 5.0.

connections.exhaustIsMaster: The number of connections whose last request was an isMaster request with exhaustAllowed.
Note
If you are running MongoDB 5.0 or later, do not use the isMaster command. Instead, use hello.
New in version 4.4.

connections.exhaustHello: The number of connections whose last request was a hello request with exhaustAllowed.
New in version 5.0: (and 4.4.2)

connections.awaitingTopologyChanges: The number of clients currently waiting in a hello or isMaster request for a topology change.
Note
If you are running MongoDB 5.0 or later, do not use the isMaster command. Instead, use hello.
New in version 4.4.

connections.loadBalanced: New in version 5.3.
The current number of incoming connections received through the load balancer.

defaultRWConcern

Available starting in 4.4

The defaultRWConcern section provides information on the local copy of the global default read or write concern settings. The data may be stale or out of date. See getDefaultRWConcern for more information.

"defaultRWConcern" : {
  "defaultReadConcern" : {
    "level" : <string>
  },
  "defaultWriteConcern" : {
    "w" : <string> | <int>,
    "wtimeout" : <int>,
    "j" : <bool>
  },
  "defaultWriteConcernSource": <string>,
  "defaultReadConcernSource": <string>,
  "updateOpTime" : Timestamp,
  "updateWallClockTime" : Date,
  "localUpdateWallClockTime" : Date
}

defaultRWConcern: The last known global default read or write concern settings.
New in version 4.4.

defaultRWConcern.defaultReadConcern

The last known global default read concern setting.

If serverStatus does not return this field, the global default read concern has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultReadConcern.level

The last known global default read concern level setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern

The last known global default write concern setting.

If serverStatus does not return this field, the global default write concern has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern.w

The last known global default w setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcern.wtimeout

The last known global default wtimeout setting.

If serverStatus does not return this field, the global default for this setting has either not been set or has not yet propagated to the instance.

New in version 4.4.

defaultRWConcern.defaultWriteConcernSource: The source of the default write concern. By default, the value is "implicit". Once you set the default write concern with setDefaultRWConcern, the value becomes "global".
New in version 5.0.

defaultRWConcern.defaultReadConcernSource: The source of the default read concern. By default, the value is "implicit". Once you set the default read concern with setDefaultRWConcern, the value becomes "global".
New in version 5.0.

defaultRWConcern.updateOpTime: The timestamp when the instance last updated its copy of any global read or write concern settings. If the defaultRWConcern.defaultReadConcern and defaultRWConcern.defaultWriteConcern fields are absent, this field indicates the timestamp when the defaults were last unset.
New in version 4.4.

defaultRWConcern.updateWallClockTime: The wall clock time when the instance last updated its copy of any global read or write concern settings. If the defaultRWConcern.defaultReadConcern and defaultRWConcern.defaultWriteConcern fields are absent, this field indicates the time when the defaults were last unset.
New in version 4.4.

defaultRWConcern.localUpdateWallClockTime: The local system wall clock time when the instance last updated its copy of any global read or write concern setting. If this field is the only field under defaultRWConcern, the instance has never had knowledge of a global default read or write concern setting.
New in version 4.4.

electionMetrics

New in version 4.2.1.

The electionMetrics section provides information on elections called by this mongod instance in a bid to become the primary:

"electionMetrics" : {
   "stepUpCmd" : {
      "called" : NumberLong(<num>),
      "successful" : NumberLong(<num>)
   },
   "priorityTakeover" : {
      "called" : NumberLong(<num>),
      "successful" : NumberLong(<num>)
   },
   "catchUpTakeover" : {
      "called" : NumberLong(<num>),
      "successful" : NumberLong(<num>)
   },
   "electionTimeout" : {
      "called" : NumberLong(<num>),
      "successful" : NumberLong(<num>)
   },
   "freezeTimeout" : {
      "called" : NumberLong(<num>),
      "successful" : NumberLong(<num>)
   },
   "numStepDownsCausedByHigherTerm" : NumberLong(<num>),
   "numCatchUps" : NumberLong(<num>),
   "numCatchUpsSucceeded" : NumberLong(<num>),
   "numCatchUpsAlreadyCaughtUp" : NumberLong(<num>),
   "numCatchUpsSkipped" : NumberLong(<num>),
   "numCatchUpsTimedOut" : NumberLong(<num>),
   "numCatchUpsFailedWithError" : NumberLong(<num>),
   "numCatchUpsFailedWithNewTerm" : NumberLong(<num>),
   "numCatchUpsFailedWithReplSetAbortPrimaryCatchUpCmd" : NumberLong(<num>),
   "averageCatchUpOps" : <double>
}

electionMetrics.stepUpCmd

Metrics on elections that were called by the mongod instance as part of an election handoff when the primary stepped down.

The stepUpCmd includes both the number of elections called and the number of elections that succeeded.

New in version 4.2.1.

electionMetrics.priorityTakeover

Metrics on elections that were called by the mongod instance because its priority is higher than the primary's.

The electionMetrics.priorityTakeover includes both the number of elections called and the number of elections that succeeded.

New in version 4.2.1.

electionMetrics.catchUpTakeover

Metrics on elections called by the mongod instance because it is more current than the primary.

The catchUpTakeover includes both the number of elections called and the number of elections that succeeded.

Tip

extra_info

"extra_info" : {
   "note" : "fields vary by platform.",
   "page_faults" : <num>
},

extra_info: A document that provides additional information about the underlying system.

extra_info.note: A string with the text "fields vary by platform."

extra_info.page_faults

The total number of page faults. The extra_info.page_faults counter may increase dramatically during moments of poor performance and may correlate with limited memory environments and larger data sets. Limited and sporadic page faults do not necessarily indicate an issue.

Windows differentiates "hard" page faults involving disk I/O from "soft" page faults that only require moving pages in memory. MongoDB counts both hard and soft page faults in this statistic.

flowControl

New in version 4.2.

"flowControl" : {
   "enabled" : <boolean>,
   "targetRateLimit" : <int>,
   "timeAcquiringMicros" : NumberLong(<num>),
   "locksPerKiloOp" : <double>,  // Available in 4.4+. In 4.2, returned locksPerOp instead.
   "sustainerRate" : <int>,
   "isLagged" : <boolean>,
   "isLaggedCount" : <int>,
   "isLaggedTimeMicros" : NumberLong(<num>)
},

flowControl: A document that returns statistics on the Flow Control. With flow control enabled, as the majority commit point lag grows close to the flowControlTargetLagSeconds, writes on the primary must obtain tickets before taking locks. As such, the metrics returned are meaningful when run on the primary.
New in version 4.2.

flowControl.enabled

A boolean that indicates whether Flow Control is enabled (true) or disabled (false).

Note

Starting in MongoDB 4.4

locksPerKiloOp replaces locksPerOp field. locksPerOp field is available only on version 4.2.

When run on the primary, an approximation of the number of locks taken per 1000 operations.

When run on a secondary, the returned number is a placeholder.

New in version 4.4.

flowControl.locksPerOp

Note

Available on MongoDB 4.2 only

MongoDB 4.4 replaces locksPerOp with flowControl.locksPerKiloOp.

When run on the primary, an approximation of the number of locks taken per operation.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.sustainerRate

When run on the primary, an approximation of operations applied per second by the secondary that is sustaining the commit point.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.isLagged

When run on the primary, a boolean that indicates whether flow control has engaged. Flow control engages when the majority committed lag is greater than some percentage of the configured flowControlTargetLagSeconds.

Replication lag can occur without engaging flow control. An unresponsive secondary might lag without the replica set receiving sufficient load to engage flow control, leaving the flowControl.isLagged value at false.

For additional information, see Flow Control.

New in version 4.2.

flowControl.isLaggedCount

When run on a primary, the number of times flow control has engaged since the last restart. Flow control engages when the majority committed lag is greater than some percentage of the flowControlTargetLagSeconds.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

flowControl.isLaggedTimeMicros

When run on the primary, the amount of time flow control has spent being engaged since the last restart. Flow control engages when the majority committed lag is greater than some percentage of the flowControlTargetLagSeconds.

When run on a secondary, the returned number is a placeholder.

New in version 4.2.

freeMonitoring

"freeMonitoring" : {
   "state" : <string>,
   "retryIntervalSecs" : NumberLong(<num>),
   "lastRunTime" : <string>,
   "registerErrors" : NumberLong(<num>),
   "metricsErrors" : NumberLong(<num>)
},

freeMonitoring: A document that reports on the free Cloud monitoring.

freeMonitoring.state

The enablement state of free monitoring. The values can be one of the following:

"enabled"
"disabled"
"pending" if the enable free monitoring encountered a registration error.

freeMonitoring.retryIntervalSecs: The frequency, in seconds, at which data is uploaded.

freeMonitoring.lastRunTime: The date and time of the last run of the metrics upload.

freeMonitoring.registerErrors: The number of registration errors, incremented on unexpected HTTP status or network errors.

freeMonitoring.metricsErrors: The number of errors encountered when uploading metrics.

globalLock

"globalLock" : {
   "totalTime" : NumberLong(<num>),
   "currentQueue" : {
      "total" : <num>,
      "readers" : <num>,
      "writers" : <num>
   },
   "activeClients" : {
      "total" : <num>,
      "readers" : <num>,
      "writers" : <num>
   }
},

globalLock

A document that reports on the database's lock state.

Generally, the locks document provides more detailed data on lock uses.

globalLock.totalTime: The time, in microseconds, since the database last started and created the globalLock. This is approximately equivalent to the total server uptime.

globalLock.currentQueue: A document that provides information concerning the number of operations queued because of a lock.

globalLock.currentQueue.total

The total number of operations queued waiting for the lock (i.e., the sum of globalLock.currentQueue.readers and globalLock.currentQueue.writers).

A consistently small queue, particularly of shorter operations, should cause no concern. The globalLock.activeClients readers and writers information provides context for this data.

globalLock.currentQueue.readers: The number of operations that are currently queued and waiting for the read lock. A consistently small read queue, particularly of shorter operations, should cause no concern.

globalLock.currentQueue.writers: The number of operations that are currently queued and waiting for the write lock. A consistently small write queue, particularly of shorter operations, is no cause for concern.

globalLock.activeClients

A document that provides information about the number of connected clients and the read and write operations performed by these clients.

Use this data to provide context for the globalLock.currentQueue data.

globalLock.activeClients.total: The total number of internal client connections to the database including system threads as well as queued readers and writers. This metric will be higher than the total of activeClients.readers and activeClients.writers due to the inclusion of system threads.

globalLock.activeClients.readers: The number of the active client connections performing read operations.

globalLock.activeClients.writers: The number of active client connections performing write operations.

hedgingMetrics

New in version 4.4: For mongos instances only.

"hedgingMetrics" : {
   "numTotalOperations" : <num>,
   "numTotalHedgedOperations" : <num>,
   "numAdvantageouslyHedgedOperations" : <num>
},

hedgingMetrics: Provides metrics on hedged reads for the mongos instance.
New in version 4.4: For mongos instances only.

hedgingMetrics.numTotalOperations: The total number of the operations issued with the hedged read option enabled to this mongos instance.
New in version 4.4: For mongos instances only.

hedgingMetrics.numTotalHedgedOperations: The number of all operations for which the mongos instance hedged the read operation; i.e. sent the operation to an additional member of each queried shard.
New in version 4.4: For mongos instances only.

hedgingMetrics.numAdvantageouslyHedgedOperations: The total number of the operation where the additional read sent to hedge the read operation fulfilled the client request.
New in version 4.4: For mongos instances only.

indexBulkBuilder

"indexBulkBuilder": {
   "count": <long>,
   "resumed": <long>,
   "filesOpenedForExternalSort": <long>,
   "filesClosedForExternalSort": <long>,
   "spilledRanges": <long>,
   "bytesSpilled": <long>
}

indexBulkBuilder: Provides metrics for index bulk builder operations. Use these metrics to diagnose index build issues with createIndexes, collection cloning during initial sync, index builds that resume after startup, and statistics on disk usage by the external sorter.

indexBuildBuilder.bytesSpilled: New in version 6.0.4.
The number of bytes written to disk by the external sorter.

indexBuilder.bytesSpilledUncompressed: New in version 6.0.4.
The number of bytes to be written to disk by the external sorter before compression.

indexBulkBuilder.count: The number of instances of the bulk builder created.

indexBulkBuilder.filesClosedForExternalSort: The number of times the external sorter closed a file handle to spill data to disk. Combine this value with filesOpenedForExternalSort to determine the number of open file handles in use by the external sorter.

indexBulkBuilder.filesOpenedForExternalSort: The number of times the external sorter opened a file handle to spill data to disk. Combine this value with filesClosedForExternalSort to determine the number of open file handles in use by the external sorter.

indexBulkBuilder.resumed: The number of times the bulk builder was created for a resumable index build.

indexBulkBuilder.spilledRanges: New in version 6.0.4.
The number of times the external sorter spilled to disk.

Instance Information

"host" : <string>,
"advisoryHostFQDNs" : <array>,
"version" : <string>,
"process" : <"mongod"|"mongos">,
"pid" : NumberLong(<num>),
"uptime" : <num>,
"uptimeMillis" : NumberLong(<num>),
"uptimeEstimate" : NumberLong(<num>),
"localTime" : ISODate(""),

host: The system's hostname. In Unix/Linux systems, this should be the same as the output of the hostname command.

advisoryHostFQDNs: An array of the system's fully qualified domain names (FQDNs).

version: The MongoDB version of the current MongoDB process.

process: The current MongoDB process. Possible values are: mongos or mongod.

pid: The process ID number.

uptime: The number of seconds that the current MongoDB process has been active.

uptimeMillis: The number of milliseconds that the current MongoDB process has been active.

uptimeEstimate: The uptime in seconds as calculated from MongoDB's internal course-grained time keeping system.

localTime: The ISODate representing the current time, according to the server, in UTC.

latchAnalysis

New in version 4.4.

"latchAnalysis" : {
   <latch name> : {
      "created" : <num>,
      "destroyed" : <num>,
      "acquired" : <num>,
      "released" : <num>,
      "contended" : <num>,
      "hierarchicalAcquisitionLevelViolations" : {
            "onAcquire" : <num>,
            "onRelease" : <num>
      }
   },
   ...

latchAnalysis

A document that reports on metrics related to internal locking primitives (also known as latches).

To return latchAnalysis information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, latchAnalysis: 1 } )

The latchAnalysis returns for each latch the <latch name> and the following associated metrics:

Metric	Description
`created`	Number of times the latch was created.
`destroyed`	Number of times the latch was destroyed.
`acquired`	Number of times the latch was acquired.
`released`	Number of times the latch was released.
`contended`	Number of times the latch had contention.
`hierarchicalAcquisitionLevelViolations`	Only returned if violations exist Contains the following fields: `onAcquire` Number of times the latch hierarchy (i.e. the latch level ordering) has been violated during latch acquisition. `onRelease` Number of times the latch hierarchy (i.e. the latch level ordering) has been violated during latch release.

New in version 4.4.

locks

"locks" : {
   <type> : {
         "acquireCount" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "acquireWaitCount" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "timeAcquiringMicros" : {
            <mode> : NumberLong(<num>),
            ...
         },
         "deadlockCount" : {
            <mode> : NumberLong(<num>),
            ...
         }
   },
   ...

locks

A document that reports for each lock <type>, data on lock <modes>.

The possible lock <types> are:

Lock Type	Description
`ParallelBatchWriterMode`	Represents a lock for parallel batch writer mode. In earlier versions, PBWM information was reported as part of the `Global` lock information. New in version 4.2.
`ReplicationStateTransition`	Represents lock taken for replica set member state transitions. New in version 4.2.
`Global`	Represents global lock.
`Database`	Represents database lock.
`Collection`	Represents collection lock.
`Mutex`	Represents mutex.
`Metadata`	Represents metadata lock.
`oplog`	Represents lock on the oplog.

The possible <modes> are:

Lock Mode	Description
`R`	Represents Shared (S) lock.
`W`	Represents Exclusive (X) lock.
`r`	Represents Intent Shared (IS) lock.
`w`	Represents Intent Exclusive (IX) lock.

All values are of the NumberLong() type.

locks.<type>.acquireCount: Number of times the lock was acquired in the specified mode.

locks.<type>.acquireWaitCount: Number of times the locks.<type>.acquireCount lock acquisitions encountered waits because the locks were held in a conflicting mode.

locks.<type>.timeAcquiringMicros

Cumulative wait time in microseconds for the lock acquisitions.

locks.<type>.timeAcquiringMicros divided by locks.<type>.acquireWaitCount gives an approximate average wait time for the particular lock mode.

locks.<type>.deadlockCount: Number of times the lock acquisitions encountered deadlocks.

logicalSessionRecordCache

"logicalSessionRecordCache" : {
   "activeSessionsCount" : <num>,
   "sessionsCollectionJobCount" : <num>,
   "lastSessionsCollectionJobDurationMillis" : <num>,
   "lastSessionsCollectionJobTimestamp" : <Date>,
   "lastSessionsCollectionJobEntriesRefreshed" : <num>,
   "lastSessionsCollectionJobEntriesEnded" : <num>,
   "lastSessionsCollectionJobCursorsClosed" : <num>,
   "transactionReaperJobCount" : <num>,
   "lastTransactionReaperJobDurationMillis" : <num>,
   "lastTransactionReaperJobTimestamp" : <Date>,
   "lastTransactionReaperJobEntriesCleanedUp" : <num>,
   "sessionCatalogSize" : <num>   // Starting in MongoDB 4.2
},

logicalSessionRecordCache: Provides metrics around the caching of server sessions.

logicalSessionRecordCache.activeSessionsCount

The number of all active local sessions cached in memory by the mongod or mongos instance since the last refresh period.

Tip

mem

"mem" : {
   "bits" : <int>,
   "resident" : <int>,
   "virtual" : <int>,
   "supported" : <boolean>
},

mem: A document that reports on the system architecture of the mongod and current memory use.

mem.bits: A number, either 64 or 32, that indicates whether the MongoDB instance is compiled for 64-bit or 32-bit architecture.

mem.resident: The value of mem.resident is roughly equivalent to the amount of RAM, in mebibyte (MiB), currently used by the database process. During normal use, this value tends to grow. In dedicated database servers, this number tends to approach the total amount of system memory.

mem.virtual: mem.virtual displays the quantity, in mebibyte (MiB), of virtual memory used by the mongod process.

mem.supported: A boolean that indicates whether the underlying system supports extended memory information. If this value is false and the system does not support extended memory information, then other mem values may not be accessible to the database server.

mem.note

The field mem.note appears if mem.supported is false.

The mem.note field contains the text: "not all mem info support on this platform".

metrics

metrics : {
   apiVersions: {
      <appName1>: <string>,
      <appName2>: <string>,
      <appName3>: <string>
   },
   aggStageCounters : {
      <aggregation stage> : Long("<num>")
   },
   commands: {
      <command>: {
         failed: Long("<num>"),
         total: Long("<num>")
      }
   },
   cursor : {
      moreThanOneBatch : Long("<num>"),
      timedOut : Long("<num>"),
      totalOpened : Long("<num>"),
      lifespan : {
         greaterThanOrEqual10Minutes : Long("<num>"),
         lessThan10Minutes : Long("<num>"),
         lessThan15Seconds : Long("<num>"),
         lessThan1Minute : Long("<num>"),
         lessThan1Second : Long("<num>"),
         lessThan30Seconds : Long("<num>"),
         lessThan5Seconds : Long("<num>")
      },
      open : {
         noTimeout : Long("<num>"),
         pinned : Long("<num>"),
         multiTarget : Long("<num>"),
         singleTarget : Long("<num>"),
         total : Long("<num>")
      }
   },
   document : {
      deleted : Long("<num>"),
      inserted : Long("<num>"),
      returned : Long("<num>"),
      updated : Long("<num>")
   },
   dotsAndDollarsFields : {
         inserts : Long("<num>"),
         updates : Long("<num>")
   },
   getLastError : {
      wtime : {
         num : <num>,
         totalMillis : <num>
      },
      wtimeouts : Long("<num>"),
      default : {
         unsatisfiable : Long("<num>"),
         wtimeouts : Long("<num>")
      }
   },
   mongos : {
      cursor : {
         moreThanOneBatch : Long("<num>"),
         totalOpened : Long("<num>")
      }
   },
   operation : {
      scanAndOrder : Long("<num>"),
      writeConflicts : Long("<num>")
   },
   operatorCounters : {
      expressions : {
         <command> : Long(<num>)
      },
      match : {
         <command> : Long(<num>)
      }
   },
   query: {
      allowDiskUseFalse: Long("<num>"),
      planCacheTotalSizeEstimateBytes: Long("<num>"),
      updateOneOpStyleBroadcastWithExactIDCount: Long("<num>"),
      lookup: {
         pipelineTotalCount: Long("<num>"),
         slotBasedExecutionCounters: {
            hashLookup: Long("<num>"),
            hashLookupSpillToDisk: Long("<num>"),
            indexedLoopJoin: Long("<num>"),
            nestedLoopJoin: Long("<num>")
         }
      },
      multiPlanner: {
         classicCount: Long("<num>"),
         classicMicros: Long("<num>"),
         classicWorks: Long("<num>"),
         sbeCount: Long("<num>"),
         sbeMicros: Long("<num>"),
         sbeNumReads: Long("<num>"),
         histograms: {
            classicMicros: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("1073741824"), count: Long("<num>")> }>
            ],
            classicNumPlans: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("32"), count: Long("<num>") }
            ],
            classicWorks: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("32768"), count: Long("<num>") }
            ],
            sbeMicros: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("1073741824"), count: Long("<num>") }
            ],
            sbeNumPlans: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("32"), count: Long("<num>") }
            ],
            sbeNumReads: [
               { lowerBound: Long("0"), count: Long("<num>") },
               { < Additional histogram groups not shown. > },
               { lowerBound: Long("32768"), count: Long("<num>") }
            ]
         }
      },
      queryFramework: {
         aggregate: {
            classicHybrid: Long("<num>"),
            classicOnly: Long("<num>"),
            cqf: Long("<num>"),
            sbeHybrid: Long("<num>"),
            sbeOnly: Long("<num>")
         },
         find: { classic: Long("<num>"), cqf: Long("<num>"), sbe: Long("<num>") }
      }
   },
   queryExecutor: {
      scanned : Long("<num>"),
      scannedObjects : Long("<num>"),
      collectionScans : {
         nonTailable : NumbeLong(<num>),
         total : Long("<num>")
      }
   },
   record : {
      moves : Long("<num>")
   },
   repl : {
      executor : {
         pool : {
            inProgressCount : <num>
         },
         queues : {
            networkInProgress : <num>,
            sleepers : <num>
         },
         unsignaledEvents : <num>,
         shuttingDown : <boolean>,
         networkInterface : <string>
      },
      apply : {
         attemptsToBecomeSecondary : Long("<num>"),
         batches : {
            num : <num>,
            totalMillis : <num>
         },
         ops : Long("<num>")
      },
      buffer : {
         count : Long("<num>"),
         maxSizeBytes : Long("<num>"),
         sizeBytes : Long("<num>")
      },
      initialSync : {
         completed : Long("<num>"),
         failedAttempts : Long("<num>"),
         failures : Long("<num>")
      },
      network : {
         bytes : Long("<num>"),
         getmores : {
            num : <num>,
            totalMillis : <num>
         },
         notPrimaryLegacyUnacknowledgedWrites : Long("<num>"),
         notPrimaryUnacknowledgedWrites : Long("<num>"),
         oplogGetMoresProcessed : {
            num : <num>,
            totalMillis : <num>
         },
         ops : Long("<num>"),
         readersCreated : Long("<num>"),
         replSetUpdatePosition : {
            num : Long("<num>")
         }
      },
      reconfig : {
         numAutoReconfigsForRemovalOfNewlyAddedFields : Long("<num>")
      },
      stepDown : {
         userOperationsKilled : Long("<num>"),
         userOperationsRunning : Long("<num>")
      },
      syncSource : {
         numSelections : Long("<num>"),
         numTimesChoseSame : Long("<num>"),
         numTimesChoseDifferent : Long("<num>"),
         numTimesCouldNotFind : Long("<num>")
      }
   },
   storage : {
      freelist : {
         search : {
            bucketExhausted : <num>,
            requests : <num>,
            scanned : <num>
         }
      }
   },
   ttl : {
      deletedDocuments : Long("<num>"),
      passes : Long("<num>")
   }
}

metrics: A document that returns various statistics that reflect the current use and state of a running mongod instance.

metrics.aggStageCounters

A document that reports on the use of aggregation pipeline stages. The fields in metrics.aggStageCounters are the names of aggregation pipeline stages. For each pipeline stage, serverStatus reports the number of times that stage has been executed.

New in version 4.4 (4.2.6 and 4.0.19). Updated in version 5.2 (and 5.0.6).

metrics.apiVersions

A document with client applications and the version of Stable API which they are configured with. Consider the following when viewing metrics.apiVersions:

The only possible returned values for each appname are default or 1.
API version metrics are retained for 24 hours. If no commands are issued with a specific API version from an application in the past 24 hours, that appname and API version will be removed from the metrics. This also applies to the default API version metric.
Set the appname when connecting to a MongoDB instance by specifying the appname in the connection URI. ?appName=ZZZ sets the appname to ZZZZ.
Drivers accessing the Stable API can set a default appname.
If no appname is configured, a default value will be automatically populated based on the product. For example, for a MongoDB Compass connection with no appname in the URI, the metric returns: 'MongoDB Compass': [ 'default' ].

New in version 5.0.

metrics.operatorCounters: A document that reports on the use of aggregation pipeline operators and expressions.

metrics.operatorCounters.expressions

A document with a number that indicates how often Expression Operators ran.

To get metrics for a specific operator, such as the greater-than operator ($gt), append the operator to the command:

db.runCommand( { serverStatus: 1 } ).metrics.operatorCounters.expressions.$gt

New in version 5.0.

metrics.operatorCounters.match

A document with a number that indicates how often match expressions ran.

Match expression operators also increment as part of an aggregation pipeline $match stage. If the $match stage uses the $expr operator, the counter for $expr increments, but the component counters do not increment.

Consider the following query:

db.matchCount.aggregate(
   [
      { $match:
         {  $expr: { $gt: [ "$_id", 0 ] } }
      }
   ]
)

The counter for $expr increments when the query runs. The counter for $gt does not.

New in version 5.1.

metrics.commands

A document that reports on the use of database commands. The fields in metrics.commands are the names of database commands. For each command, the serverStatus reports the total number of executions and the number of failed executions.

metrics.commands includes replSetStepDownWithForce (i.e. the replSetStepDown command with force: true) as well as the overall replSetStepDown. In earlier versions, the command reported only overall replSetStepDown metrics.

metrics.commands.<command>.failed: The number of times <command> failed on this mongod.

metrics.commands.<command>.total: The number of times <command> executed on this mongod.

metrics.commands.update.pipeline

The number of times an aggregation pipeline was used to update documents on this mongod. Subtract this value from the total number of updates to get the number of updates made with document syntax.

The pipeline counter is only available for update and findAndModify operations.

metrics.commands.findAndModify.pipeline

The number of times findAndModify() was used in an aggregation pipeline to update documents on this mongod.

The pipeline counter is only available for update and findAndModify operations.

metrics.commands.update.arrayFilters

The number of times an arrayFilter was used to update documents on this mongod.

The arrayFilters counter is only available for update and findAndModify operations.

metrics.commands.findAndModify.arrayFilters

The number of times an arrayFilter was used with findAndModify() to update documents on this mongod.

The arrayFilters counter is only available for update and findAndModify operations.

metrics.document: A document that reflects document access and modification patterns. Compare these values to the data in the opcounters document, which track total number of operations.

metrics.document.deleted: The total number of documents deleted.

metrics.document.inserted: The total number of documents inserted.

metrics.document.returned: The total number of documents returned by queries.

metrics.document.updated: The total number of documents updated.

metrics.dotsAndDollarsFields

A document with a number that indicates how often insert or update operations ran using a dollar ($) prefixed name. The value does not report the exact number of operations.

When an upsert operation creates a new document, it is considered to be an insert rather than an update.

New in version 5.0.

metrics.executor: A document that reports on various statistics for the replication executor.

metrics.getLastError: A document that reports on write concern use.

metrics.getLastError.wtime: A document that reports write concern operation counts with a w argument greater than 1.

metrics.getLastError.wtime.num: The total number of operations with a specified write concern (i.e. w) that wait for one or more members of a replica set to acknowledge the write operation (i.e. a w value greater than 1.)

metrics.getLastError.wtime.totalMillis: The total amount of time in milliseconds that the mongod has spent performing write concern operations with a write concern (i.e. w) that waits for one or more members of a replica set to acknowledge the write operation (i.e. a w value greater than 1.)

metrics.getLastError.wtimeouts: The number of times that write concern operations have timed out as a result of the wtimeout threshold. This number increments for both default and non-default write concern specifications.

metrics.getLastError.default

A document that reports on when a default write concern was used (meaning, a non-clientSupplied write concern). The possible origins of a default write concern are:

implicitDefault
customDefault
getLastErrorDefaults

Refer to the following table for information on each possible write concern origin, or provenance:

Provenance	Description
`clientSupplied`	The write concern was specified in the application.
`customDefault`	The write concern originated from a custom defined default value. See `setDefaultRWConcern`.
`getLastErrorDefaults`	The write concern originated from the replica set's `settings.getLastErrorDefaults` field.
`implicitDefault`	The write concern originated from the server in absence of all other write concern specifications.

metrics.getLastError.default.unsatisfiable: Number of times that a non-clientSupplied write concern returned the UnsatisfiableWriteConcern error code.

metrics.getLastError.default.wtimeouts: Number of times a non-clientSupplied write concern timed out.

metrics.mongos: A document that contains metrics about mongos.

metrics.mongos.cursor: A document that contains metrics for cursors used by mongos.

metrics.mongos.cursor.moreThanOneBatch: The total number of cursors that have returned more than one batch since mongos started. Additional batches are retrieved using the getMore command.
New in version 5.0.

metrics.mongos.cursor.totalOpened: The total number of cursors that have been opened since mongos started, including cursors currently open. Differs from metrics.cursor.open.total, which is the number of currently open cursors only.
New in version 5.0.

metrics.operation: A document that holds counters for several types of update and query operations that MongoDB handles using special operation types.

metrics.operation.scanAndOrder: The total number of queries that return sorted numbers that cannot perform the sort operation using an index.

metrics.operation.writeConflicts: The total number of queries that encountered write conflicts.

metrics.query.multiPlanner

Provides detailed query planning data for the slot-based query execution engine and the classic query engine. For more information on the slot-based query execution engine see: Slot-Based Query Execution Engine Pipeline Optimizations.

These metrics are primarily intended for internal use by MongoDB.

New in version 6.0.0, 5.0.9, and 4.4.15

query.multiPlanner.classicMicros: Aggregates the total number of microseconds spent in the classic multiplanner.

query.multiPlanner.classicWorks: Aggregates the total number of "works" performed in the classic multiplanner.

query.multiPlanner.classicCount: Aggregates the total number of invocations of the classic multiplanner.

query.multiPlanner.sbeMicros: Aggregates the total number of microseconds spent in the slot-based engine multiplanner.

query.multiPlanner.sbeNumReads: Aggregates the total number of reads done in the slot-based engine multiplanner.

query.multiPlanner.sbeCount: Aggregates the total number of invocations of the slot-based engine multiplanner.

query.multiPlanner.histograms.classicMicros: A histogram measuring the number of microseconds spent in an invocation of the classic multiplanner.

query.multiPlanner.histograms.classicWorks: A histogram measuring the number of "works" performed during an invocation of the classic multiplanner.

query.multiPlanner.histograms.classicNumPlans: A histogram measuring the number of plans in the candidate set during an invocation of the classic multiplanner.

query.multiPlanner.histograms.sbeMicros: A histogram measuring the number of microseconds spent in an invocation of the slot-based engine multiplanner.

query.multiPlanner.histograms.sbeNumReads: A histogram measuring the number of reads during an invocation of the slot-based engine multiplanner.

query.multiPlanner.histograms.sbeNumPlans: A histogram measuring the number of plans in the candidate set during an invocation of the slot-based engine multiplanner.

query.queryFramework.aggregate: A document that reports on the number of aggregation operations run on each query framework. The subfields in query.queryFramework.aggregate indicate the number of times each framework was used to perform an aggregation operation.

query.queryFramework.find: A document that reports on the number of find operations run on each query framework. The subfields in query.queryFramework.find indicate the number of times each framework was used to perform a find operation.

metrics.queryExecutor: A document that reports data from the query execution system.

metrics.queryExecutor.scanned: The total number of index items scanned during queries and query-plan evaluation. This counter is the same as totalKeysExamined in the output of explain().

metrics.queryExecutor.scannedObjects: The total number of documents scanned during queries and query-plan evaluation. This counter is the same as totalDocsExamined in the output of explain().

metrics.queryExecutor.collectionScans: A document that reports on the number of queries that performed a collection scan.
New in version 4.4.

metrics.queryExecutor.collectionScans.nonTailable: The number of queries that performed a collection scan that did not use a tailable cursor.
New in version 4.4.

metrics.queryExecutor.collectionScans.total: The total number queries that performed a collection scan. The total consists of queries that did and did not use a tailable cursor.
New in version 4.4.

metrics.record: A document that reports on data related to record allocation in the on-disk memory files.

metrics.repl: A document that reports metrics related to the replication process. metrics.repl document appears on all mongod instances, even those that aren't members of replica sets.

metrics.repl.apply: A document that reports on the application of operations from the replication oplog.

metrics.repl.apply.batchSize

The total number of oplog operations applied. The metrics.repl.apply.batchSize is incremented with the number of operations in a batch at the batch boundaries instead of being incremented by one after each operation.

For finer granularity, see metrics.repl.apply.ops.

metrics.repl.apply.batches: metrics.repl.apply.batches reports on the oplog application process on secondaries members of replica sets. See Multithreaded Replication for more information on the oplog application processes.

metrics.repl.apply.batches.num: The total number of batches applied across all databases.

metrics.repl.apply.batches.totalMillis: The total amount of time in milliseconds the mongod has spent applying operations from the oplog.

metrics.repl.apply.ops: The total number of oplog operations applied. metrics.repl.apply.ops is incremented after each operation.
Tip
See also:
metrics.repl.apply.batchSize

metrics.repl.buffer: MongoDB buffers oplog operations from the replication sync source buffer before applying oplog entries in a batch. metrics.repl.buffer provides a way to track the oplog buffer. See Multithreaded Replication for more information on the oplog application process.

metrics.repl.buffer.count: The current number of operations in the oplog buffer.

metrics.repl.buffer.maxSizeBytes: The maximum size of the buffer. This value is a constant setting in the mongod, and is not configurable.

metrics.repl.buffer.sizeBytes: The current size of the contents of the oplog buffer.

metrics.repl.network: metrics.repl.network reports network use by the replication process.

metrics.repl.network.bytes: metrics.repl.network.bytes reports the total amount of data read from the replication sync source.

metrics.repl.network.getmores: metrics.repl.network.getmores reports on the getmore operations, which are requests for additional results from the oplog cursor as part of the oplog replication process.

metrics.repl.network.getmores.num: metrics.repl.network.getmores.num reports the total number of getmore operations, which are operations that request an additional set of operations from the replication sync source.

metrics.repl.network.getmores.totalMillis: metrics.repl.network.getmores.totalMillis reports the total amount of time required to collect data from getmore operations.
Note
This number can be quite large, as MongoDB will wait for more data even if the getmore operation does not initial return data.

metrics.repl.network.getmores.numEmptyBatches

The number of empty oplog batches a secondary receives from its sync source. A secondary receives an empty batch if it is fully synced with its source and either:

The getmore times out waiting for more data, or
The sync source's majority commit point has advanced since the last batch sent to this secondary.

For a primary, if the instance was previously a secondary, the number reports on the empty batches received when it was a secondary. Otherwise, for a primary, this number is 0.

New in version 4.4.

metrics.repl.network.notPrimaryLegacyUnacknowledgedWrites: The number of unacknowledged (w: 0) legacy write operations (see Opcodes) that failed because the current mongod is not in PRIMARY state.
New in version 4.2.

metrics.repl.network.notPrimaryUnacknowledgedWrites: The number of unacknowledged (w: 0) write operations that failed because the current mongod is not in PRIMARY state.
New in version 4.2.

metrics.repl.network.oplogGetMoresProcessed: A document that reports the number of getMore commands to fetch the oplog that a node processed as a sync source.
New in version 4.4.

metrics.repl.network.oplogGetMoresProcessed.num: The number of getMore commands to fetch the oplog that a node processed as a sync source.
New in version 4.4.

metrics.repl.network.oplogGetMoresProcessed.totalMillis: The time, in milliseconds, that a node spent processing the getMore commands counted in metrics.repl.network.oplogGetMoresProcessed.num.
New in version 4.4.

metrics.repl.network.ops: The total number of operations read from the replication source.

metrics.repl.network.readersCreated: The total number of oplog query processes created. MongoDB will create a new oplog query any time an error occurs in the connection, including a timeout, or a network operation. Furthermore, metrics.repl.network.readersCreated will increment every time MongoDB selects a new source for replication.

metrics.repl.network.replSetUpdatePosition: A document that reports the number of replSetUpdatePosition commands a node sent to its sync source.
New in version 4.4.

metrics.repl.network.replSetUpdatePosition.num: The number of replSetUpdatePosition commands a node sent to its sync source. replSetUpdatePosition commands are internal replication commands that communicate replication progress from nodes to their sync sources.
New in version 4.4.
Note
Replica set members in the STARTUP2 state do not send the replSetUpdatePosition command to their sync source.

metrics.repl.reconfig: A document containing the number of times that member newlyAdded fields were automatically removed by the primary. When a member is first added to the replica set, the member's newlyAdded field is set to true.
New in version 5.0.

metrics.repl.reconfig.numAutoReconfigsForRemovalOfNewlyAddedFields: The number of times that newlyAdded member fields were automatically removed by the primary. When a member is first added to the replica set, the member's newlyAdded field is set to true. After the primary receives the member's heartbeat response indicating the member state is SECONDARY, RECOVERING, or ROLLBACK, the primary automatically removes the member's newlyAdded field. The newlyAdded fields are stored in the local.system.replset collection.
New in version 5.0.

metrics.repl.stepDown: Information on user operations that were running when the mongod stepped down.
New in version 4.2.

metrics.repl.stepDown.userOperationsKilled: The number of user operations killed when the mongod stepped down.
New in version 4.2.

metrics.repl.stepDown.userOperationsRunning: The number of user operations that remained running when the mongod stepped down.
New in version 4.2.

metrics.repl.syncSource: Information on a replica set node's sync source selection process.
New in version 4.4.

metrics.repl.syncSource.numSelections: Number of times a node attempted to choose a node to sync from among the available sync source options. A node attempts to choose a node to sync from if, for example, the sync source is re-evaluated or the node receives an error from its current sync source.
New in version 4.4.

metrics.repl.syncSource.numTimesChoseSame: Number of times a node kept its original sync source after re-evaluating if its current sync source was optimal.
New in version 4.4.

metrics.repl.syncSource.numTimesChoseDifferent: Number of times a node chose a new sync source after re-evaluating if its current sync source was optimal.
New in version 4.4.

metrics.repl.syncSource.numTimesCouldNotFind: Number of times a node could not find an available sync source when attempting to choose a node to sync from.
New in version 4.4.

metrics.storage.freelist.search.bucketExhausted: The number of times that mongod has examined the free list without finding a large record allocation.

metrics.storage.freelist.search.requests: The number of times mongod has searched for available record allocations.

metrics.storage.freelist.search.scanned: The number of available record allocations mongod has searched.

metrics.ttl: A document that reports on the operation of the resource use of the ttl index process.

metrics.ttl.deletedDocuments: The total number of documents deleted from collections with a ttl index.

metrics.ttl.passes: The number of times the background process removes documents from collections with a ttl index.

metrics.cursor: A document that contains data regarding cursor state and use.

metrics.cursor.moreThanOneBatch: The total number of cursors that have returned more than one batch since the server process started. Additional batches are retrieved using the getMore command.
New in version 5.0.

metrics.cursor.timedOut: The total number of cursors that have timed out since the server process started. If this number is large or growing at a regular rate, this may indicate an application error.

metrics.cursor.totalOpened: The total number of cursors that have been opened since the server process started, including cursors currently open. Differs from metrics.cursor.open.total, which is the number of currently open cursors only.
New in version 5.0.

metrics.cursor.lifespan

A document that reports the number of cursors that have lifespans within specified time periods. The cursor lifespan is the time period from when the cursor is created to when the cursor is killed using the killCursors command or the cursor has no remaining objects in the batch.

The lifespan time periods are:

< 1 second
>= 1 second to < 5 seconds
>= 5 seconds to < 15 seconds
>= 15 seconds to < 30 seconds
>= 30 seconds to < 1 minute
>= 1 minute to < 10 minutes
>= 10 minutes

New in version 5.0.

metrics.cursor.lifespan.greaterThanOrEqual10Minutes: The number of cursors with a lifespan >= 10 minutes.
New in version 5.0.

metrics.cursor.lifespan.lessThan10Minutes: The number of cursors with a lifespan >= 1 minute to < 10 minutes.
New in version 5.0.

metrics.cursor.lifespan.lessThan15Seconds: The number of cursors with a lifespan >= 5 seconds to < 15 seconds.
New in version 5.0.

metrics.cursor.lifespan.lessThan1Minute: The number of cursors with a lifespan >= 30 seconds to < 1 minute.
New in version 5.0.

metrics.cursor.lifespan.lessThan1Second: The number of cursors with a lifespan < 1 second.
New in version 5.0.

metrics.cursor.lifespan.lessThan30Seconds: The number of cursors with a lifespan >= 15 seconds to < 30 seconds.
New in version 5.0.

metrics.cursor.lifespan.lessThan5Seconds: The number of cursors with a lifespan >= 1 second to < 5 seconds.
New in version 5.0.

metrics.cursor.open: A document that contains data regarding open cursors.

metrics.cursor.open.noTimeout: The number of open cursors with the option DBQuery.Option.noTimeout set to prevent timeout after a period of inactivity.

metrics.cursor.open.pinned: The number of "pinned" open cursors.

metrics.cursor.open.total: The number of cursors that MongoDB is maintaining for clients. Because MongoDB exhausts unused cursors, typically this value small or zero. However, if there is a queue, or stale tailable cursors, or a large number of operations this value may increase.

metrics.cursor.open.singleTarget: The total number of cursors that only target a single shard. Only mongos instances report metrics.cursor.open.singleTarget values.

metrics.cursor.open.multiTarget: The total number of cursors that only target more than one shard. Only mongos instances report metrics.cursor.open.multiTarget values.

mirroredReads

Available on mongod only.

"mirroredReads" : {
      "seen" : <num>,
      "sent" : <num>
},

mirroredReads

Available on mongod only.

A document that reports on mirrored reads. To return mirroredReads information, you must explicitly specify the inclusion:

db.runCommand( { serverStatus: 1, mirroredReads: 1 } )

mirroredReads.seen: New in version 4.4.
The number of operations that support mirroring received by this member.
Tip
See also:
mirrorReads Parameter

mirroredReads.sent: New in version 4.4.
The number of mirrored reads sent by this member when primary. For example, if a read is mirrored and sent to two secondaries, the number of mirrored reads is 2.
Tip
See also:
mirrorReads Parameter

network

"network" : {
   "bytesIn" : NumberLong(<num>),
   "bytesOut" : NumberLong(<num>),
   "numSlowDNSOperations" : NumberLong(<num>),
   "numSlowSSLOperations" : NumberLong(<num>),
   "numRequests" : NumberLong(<num>),
   "tcpFastOpen" : {
      "kernelSetting" : NumberLong(<num>),
      "serverSupported" : <bool>,
      "clientSupported" : <bool>,
      "accepted" : NumberLong(<num>)
   },
   "serviceExecutors" : {
      "passthrough" : {
         "threadsRunning" : <num>,
         "clientsInTotal" : <num>,
         "clientsRunning" : <num>,
         "clientsWaitingForData" : <num>
      },
      "fixed" : {
         "threadsRunning" : <num>,
         "clientsInTotal" : <num>,
         "clientsRunning" : <num>,
         "clientsWaitingForData" : <num>
      }
   },
}

network: A document that reports data on MongoDB's network use. These statistics measure ingress connections only, specifically the traffic seen by the mongod or mongos over network connections initiated by clients or other mongod or mongos instances. Traffic from network connections initiated by this mongod or mongos instance (specifically, egress connections) is not measured in these statistics.

network.bytesIn: The total number of bytes that the server has received over network connections initiated by clients or other mongod or mongos instances.

network.bytesOut: The total number of bytes that the server has sent over network connections initiated by clients or other mongod or mongos instances.

network.numSlowDNSOperations: New in version 4.4.
The total number of DNS resolution operations which took longer than 1 second.

network.numSlowSSLOperations: New in version 4.4.
The total number of SSL handshake operations which took longer than 1 second.

network.numRequests: The total number of distinct requests that the server has received. Use this value to provide context for the network.bytesIn and network.bytesOut values to ensure that MongoDB's network utilization is consistent with expectations and application use.

network.tcpFastOpen: New in version 4.4.
A document that reports data on MongoDB's support and use of TCP Fast Open (TFO) connections.

network.tcpFastOpen.kernelSetting

New in version 4.4.

Linux only

Returns the value of /proc/sys/net/ipv4/tcp_fastopen:

0 - TCP Fast Open is disabled on the system.
1 - TCP Fast Open is enabled for outgoing connections.
2 - TCP Fast Open is enabled for incoming connections.
3 - TCP Fast Open is enabled for incoming and outgoing connections.

network.tcpFastOpen.serverSupported

New in version 4.4.

Returns true if the host operating system supports inbound TCP Fast Open (TFO) connections.
Returns false if the host operating system does not support inbound TCP Fast Open (TFO) connections.

network.tcpFastOpen.clientSupported

New in version 4.4.

Returns true if the host operating system supports outbound TCP Fast Open (TFO) connections.
Returns false if the host operating system does not support outbound TCP Fast Open (TFO) connections.

network.tcpFastOpen.accepted: New in version 4.4.
The total number of accepted incoming TCP Fast Open (TFO) connections to the mongod or mongos since the mongod or mongos last started.

network.serviceExecutors: New in version 5.0.
A document that reports data on the service executors, which run operations for client requests.

network.serviceExecutors.passthrough: New in version 5.0.
A document that reports data about the threads and clients for the passthrough service executor. The passthrough service executor creates a new thread for each client and destroys the thread after the client ends.

network.serviceExecutors.passthrough.threadsRunning: New in version 5.0.
Number of threads running in the passthrough service executor.

network.serviceExecutors.passthrough.clientsInTotal: New in version 5.0.
Total number of clients allocated to the passthrough service executor. A client can be allocated to the passthrough service executor and not currently running requests.

network.serviceExecutors.passthrough.clientsRunning: New in version 5.0.
Number of clients currently using the passthrough service executor to run requests.

network.serviceExecutors.passthrough.clientsWaitingForData: New in version 5.0.
Number of clients using the passthrough service executor that are waiting for incoming data from the network.

network.serviceExecutors.fixed: New in version 5.0.
A document that reports data about the threads and clients for the fixed service executor. The fixed service executor has a fixed number of threads. A thread is temporarily assigned to a client and the thread is preserved after the client ends.

network.serviceExecutors.fixed.threadsRunning: New in version 5.0.
Number of threads running in the fixed service executor.

network.serviceExecutors.fixed.clientsInTotal: New in version 5.0.
Total number of clients allocated to the fixed service executor. A client can be allocated to the fixed service executor and not currently running requests.

network.serviceExecutors.fixed.clientsRunning: New in version 5.0.
Number of clients currently using the fixed service executor to run requests.

network.serviceExecutors.fixed.clientsWaitingForData: New in version 5.0.
Number of clients using the fixed service executor that are waiting for incoming data from the network.

opLatencies

Only for ``mongod`` instances

"opLatencies" : {
   "reads" : <document>,
   "writes" : <document>,
   "commands" : <document>
},

opLatencies

A document containing operation latencies for the instance as a whole. See latencyStats Document for an description of this document.

Only mongod instances report opLatencies.

opLatencies.reads: Latency statistics for read requests.

opLatencies.writes: Latency statistics for write operations.

opLatencies.commands: Latency statistics for database commands.

opReadConcernCounters

Warning

Removed

Starting in version 5.0, opReadConcernCounters is replaced by readConcernCounters.

Only for mongod instances

"opReadConcernCounters" : {
   "available" : NumberLong(<num>),
   "linearizable" : NumberLong(<num>),
   "local" : NumberLong(<num>),
   "majority" : NumberLong(<num>),
   "snapshot" : NumberLong(<num>),
   "none" : NumberLong(<num>)
}

opReadConcernCounters

Removed in version 5.0. Replaced by readConcernCounters.

A document that reports on the read concern level specified by query operations to the mongod instance since it last started.

Specified `w`	Description
`"available"`	Number of query operations that specified read concern level `"available"`.
`"linearizable"`	Number of query operations that specified read concern level `"linearizable"`.
`"local"`	Number of query operations that specified read concern level `"local"`.
`"majority"`	Number of query operations that specified read concern level `"majority"`.
`"snapshot"`	Number of query operations that specified read concern level `"snapshot"`.
`"none"`	Number of query operations that did not specify a read concern level and instead used the default read concern level.

The sum of the opReadConcernCounters equals opcounters.query.

opWriteConcernCounters

Only for mongod instances

"opWriteConcernCounters" : {
   "insert" : {
      "wmajority" : NumberLong(<num>),
      "wnum" : {
         "<num>" :  NumberLong(<num>),
         ...
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>),
      "noneInfo" : {
         "CWWC" : {
            "wmajority" : NumberLong(<num>),
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            },
            "wtag" : {
               "<tag1>" :  NumberLong(<num>),
               ...
            }
         },
         "implicitDefault" : {
            "wmajority" : NumberLong(<num>)
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            }
         }
      }
   },
   "update" : {
      "wmajority" : NumberLong(<num>),
      "wnum" : {
         "<num>" :  NumberLong(<num>),
         ...
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>),
      "noneInfo" : {
         "CWWC" : {
            "wmajority" : NumberLong(<num>),
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            }
            "wtag" : {
               "<tag1>" :  NumberLong(<num>),
               ...
            }
         },
         "implicitDefault" : {
            "wmajority" : NumberLong(<num>)
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            }
         }
      }
   },
   "delete" : {
      "wmajority" :  NumberLong(<num>)
      "wnum" : {
         "<num>" :  NumberLong(<num>),
         ...
      },
      "wtag" : {
         "<tag1>" :  NumberLong(<num>),
         ...
      },
      "none" : NumberLong(<num>),
      "noneInfo" : {
         "CWWC" : {
            "wmajority" : NumberLong(<num>),
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            },
            "wtag" : {
               "<tag1>" :  NumberLong(<num>),
               ...
            }
         },
         "implicitDefault" : {
            "wmajority" : NumberLong(<num>)
            "wnum" : {
               "<num>" :  NumberLong(<num>),
               ...
            }
         }
      }
   }
}

opWriteConcernCounters

A document that reports on the write concerns specified by write operations to the mongod instance since it last started.

More specifically, the opWriteConcernCounters reports on the w: <value> specified by the write operations. The journal flag option (j) and the timeout option (wtimeout) of the write concerns does not affect the count. The count is incremented even if the operation times out.

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

opWriteConcernCounters.insert

A document that reports on the w: <value> specified by insert operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"insert" : {
   "wmajority" : NumberLong(<num>),
   "wnum" : {
      "<num>" :  NumberLong(<num>),
      ...
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>),
   "noneInfo" : {
      "CWWC" : {
         "wmajority" : NumberLong(<num>),
         "wnum" : {},
         "wtag" : {}
      },
      "implicitDefault" : {
         "wmajority" : NumberLong(<num>)
         "wnum" : {}
      }
   }
},

Specified `w`	Description
`"wmajority"`	Number of insert operations that specified `w: "majority"`.
`"wnum"`	Number of insert operations that specified `w: <num>`. The counts are grouped by the specific``<num>``.
`"wtag"`	Number of insert operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of insert operations that did not specify `w` value. These operations use the default `w` value of "majority".
`"noneInfo"`	Number of non-transaction query operations that use default write concerns. The metrics track usage of the `cluster wide write concern` (the global default write concern) and the implicit-default write concern. The sum of the values in `opWriteConcernCounters.noneInfo` should equal the value of `opWriteConcernCounters.none`.

The sum of the opWriteConcernCounters.insert equals opcounters.insert.

opWriteConcernCounters.update

A document that reports on the w: <value> specified by update operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"update" : {
   "wmajority" : NumberLong(<num>),
   "wnum" : {
      "<num>" :  NumberLong(<num>),
      ...
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>),
   "noneInfo" : {
      "CWWC" : {
         "wmajority" : NumberLong(<num>),
         "wnum" : {},
         "wtag" : {}
      },
      "implicitDefault" : {
         "wmajority" : NumberLong(<num>)
         "wnum" : {}
      }
   }
},

Specified `w`	Description
`"wmajority"`	Number of update operations that specified `w: "majority"`.
`"wnum"`	Number of update operations that specified `w: <num>`. The counts are grouped by the specific `<num>`.
`"wtag"`	Number of update operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of update operations that did not specify `w` value. These operations use the default `w` value of `1`.
`"noneInfo"`	Number of non-transaction query operations that use default write concerns. The metrics track usage of the `cluster wide write concern` (the global default write concern) and the implicit-default write concern. The sum of the values in `opWriteConcernCounters.noneInfo` should equal the value of `opWriteConcernCounters.none`.

The sum of the opWriteConcernCounters.update equals opcounters.update.

opWriteConcernCounters.delete

A document that reports on the w: <value> specified by delete operations to the mongod instance since it last started:

Note

Only available when reportOpWriteConcernCountersInServerStatus parameter is set to true (false by default).

"delete" : {
   "wmajority" :  NumberLong(<num>),
   "wnum" : {
      "<num>" :  NumberLong(<num>),
      ...
   },
   "wtag" : {
      "<tag1>" :  NumberLong(<num>),
      ...
   },
   "none" : NumberLong(<num>),
   "noneInfo" : {
      "CWWC" : {
         "wmajority" : NumberLong(<num>),
         "wnum" : {},
         "wtag" : {}
      },
      "implicitDefault" : {
         "wmajority" : NumberLong(<num>)
         "wnum" : {}
      }
   }
}

Specified `w`	Description
`"wmajority"`	Number of delete operations that specified `w: "majority"`.
`"wnum"`	Number of delete operations that specified `w: <num>`. The counts are grouped by the specific `<num>`.
`"wtag"`	Number of delete operations that specified `w: <tag>`. The counts are grouped by the specific `<tag>`.
`"none"`	Number of delete operations that did not specify `w` value. These operations use the default `w` value of `1`.
`"noneInfo"`	Number of non-transaction query operations that use default write concerns. The metrics track usage of the `cluster wide write concern` (the global default write concern) and the implicit-default write concern. The sum of the values in `opWriteConcernCounters.noneInfo` should equal the value of `opWriteConcernCounters.none`.

The sum of the opWriteConcernCounters.delete equals opcounters.delete.

opcounters

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

"opcounters" : {
   "insert" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "query" : NumberLong(<num>),   // Starting in MongoDB 4.2, type is NumberLong
   "update" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "delete" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "getmore" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
   "command" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
},

opcounters

A document that reports on database operations by type since the mongod instance last started.

These numbers will grow over time until next restart. Analyze these values over time to track database utilization.

Note

The data in opcounters treats operations that affect multiple documents, such as bulk insert or multi-update operations, as a single operation. See metrics.document for more granular document-level operation tracking.

Additionally, these values reflect received operations, and increment even when operations are not successful.

opcounters.insert

The total number of insert operations received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.query

The total number of queries received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.update

The total number of update operations received since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.delete

The total number of delete operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.getmore

The total number of getMore operations since the mongod instance last started. This counter can be high even if the query count is low. Secondary nodes send getMore operations as part of the replication process.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.command

The total number of commands issued to the database since the mongod instance last started.

opcounters.command counts all commands except the write commands: insert, update, and delete.

Starting in MongoDB 4.2, the returned opcounters.* values are type NumberLong. In previous versions, the values are of type NumberInt.

opcounters.deprecated

opQuery counts the number of requests for opcodes that are deprecated in MongoDB 5.0 but are temporarily supported. This section only appears in the db.serverStatus() output when a deprecated opcode has been used.

The counter is reset when mongod starts.

"deprecated": {
   "opQuery": NumberLong(<num>),
}

opcountersRepl

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

"opcountersRepl" : {
   "insert" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "query" : NumberLong(<num>),   // Starting in MongoDB 4.2, type is NumberLong
   "update" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "delete" : NumberLong(<num>),  // Starting in MongoDB 4.2, type is NumberLong
   "getmore" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
   "command" : NumberLong(<num>), // Starting in MongoDB 4.2, type is NumberLong
},

opcountersRepl

A document that reports on database replication operations by type since the mongod instance last started.

These values only appear when the current host is a member of a replica set.

These values will differ from the opcounters values because of how MongoDB serializes operations during replication. See Replication for more information on replication.

These numbers will grow over time in response to database use until next restart. Analyze these values over time to track database utilization.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.insert

The total number of replicated insert operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.query

The total number of replicated queries since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.update

The total number of replicated update operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.delete

The total number of replicated delete operations since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.getmore

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

opcountersRepl.command

The total number of replicated commands issued to the database since the mongod instance last started.

Starting in MongoDB 4.2, the returned opcountersRepl.* values are type NumberLong. In previous versions, the values are type NumberInt.

oplogTruncation

"oplogTruncation" : {
   "totalTimeProcessingMicros" : NumberLong(<num>),
   "processingMethod" : <string>,
   "oplogMinRetentionHours" : <double>
   "totalTimeTruncatingMicros" : NumberLong(<num>),
   "truncateCount" : NumberLong(<num>)
},

oplogTruncation

A document that reports on oplog truncations.

The field only appears when the current instance is a member of a replica set and uses either the WiredTiger Storage Engine or In-Memory Storage Engine.

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.totalTimeProcessingMicros

The total time taken, in microseconds, to scan or sample the oplog to determine the oplog truncation points.

totalTimeProcessingMicros is only meaningful if the mongod instance started on existing data files (i.e. not meaningful for In-Memory Storage Engine).

See oplogTruncation.processingMethod

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.processingMethod

The method used at start up to determine the oplog truncation points. The value can be either "sampling" or "scanning".

processingMethod is only meaningful if the mongod instance started on existing data files (i.e. not meaningful for In-Memory Storage Engine).

Changed in version 4.4: Also available in In-Memory Storage Engine.

New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.minRetentionHours

New in version 4.4: The minimum retention period for the oplog in hours. If the oplog has exceeded the oplog size, the mongod only truncates oplog entries older than the configured retention value.

Only visible if the mongod is a member of a replica set and:

The mongod was started with the --oplogMinRetentionHours command line option or the storage.oplogMinRetentionHours configuration file option,
or
The minimum retention period was configured after startup using replSetResizeOplog.

oplogTruncation.totalTimeTruncatingMicros: The cumulative time spent, in microseconds, performing oplog truncations.
Changed in version 4.4: Also available in In-Memory Storage Engine.
New in version 4.2.1: Available in the WiredTiger Storage Engine.

oplogTruncation.truncateCount: The cumulative number of oplog truncations.
Changed in version 4.4: Also available in In-Memory Storage Engine.
New in version 4.2.1: Available in the WiredTiger Storage Engine.

readConcernCounters

New in version 5.0.

"readConcernCounters" : {
   "nonTransactionOps" : {
      "none" : NumberLong(<num>),
      "noneInfo" : {
         "CWRC" : {
            "local" : NumberLong(<num>),
            "available" : NumberLong(<num>),
            "majority" : NumberLong(<num>)
         },
         "implicitDefault" : {
            "local" : NumberLong(<num>),
            "available" : NumberLong(<num>)
         }
      },
      "local" : NumberLong(<num>),
      "available" : NumberLong(<num>),
      "majority" : NumberLong(<num>),
      "snapshot" : {
         "withClusterTime" : NumberLong(<num>),
         "withoutClusterTime" : NumberLong(<num>)
      },
      "linearizable" : NumberLong(<num>)
   },
   "transactionOps" : {
      "none" : NumberLong(<num>),
      "noneInfo" : {
         "CWRC" : {
            "local" : NumberLong(<num>),
            "available" : NumberLong(<num>),
            "majority" : NumberLong(<num>)
         },
         "implicitDefault" : {
            "local" : NumberLong(<num>),
            "available" : NumberLong(<num>)
         }
      },
      "local" : NumberLong(<num>),
      "majority" : NumberLong(<num>),
      "snapshot" : {
         "withClusterTime" : NumberLong(<num>),
         "withoutClusterTime" : NumberLong(<num>)
      }
   }
},

readConcernCounters: A document that reports on the read concern level specified by query operations. This document contains the readConcernCounters.nonTransactionOps and readConcernCounters.transactionOps documents.

readConcernCounters.nonTransactionOps: A document that reports on the read concern level specified by non-transaction query operations performed after the database server last started.

readConcernCounters.nonTransactionOps.none

Number of non-transaction query operations that did not specify a read concern level and instead used either:

the default read concern level, or
the global default read concern configuration if it was set by the setDefaultRWConcern command.

readConcernCounters.nonTransactionOps.noneInfo

The number of non-transaction query operations that use the global default read concern and an implicit-default read concern.

The sum of the values in readConcernCounters.nonTransactionOps.noneInfo should equal the value of readConcernCounters.nonTransactionOps.none.

readConcernCounters.nonTransactionOps.local: Number of non-transaction query operations that specified the "local" read concern level.

readConcernCounters.nonTransactionOps.available: Number of non-transaction query operations that specified the "available" read concern level.

readConcernCounters.nonTransactionOps.majority: Number of non-transaction query operations that specified the "majority" read concern level.

readConcernCounters.nonTransactionOps.snapshot: Document containing non-transaction query operations that specified the "snapshot" read concern level.

readConcernCounters.nonTransactionOps.snapshot.withClusterTime: Number of non-transaction query operations that specified the "snapshot" read concern level and the cluster time, which specified a point in time.

readConcernCounters.nonTransactionOps.snapshot.withoutClusterTime: Number of non-transaction query operations that specified the "snapshot" read concern level without the cluster time, which means a point in time was omitted and the server will read the most recently committed snapshot available to the node.

readConcernCounters.nonTransactionOps.linearizable: Number of non-transaction query operations that specified the "linearizable" read concern level.

readConcernCounters.transactionOps: A document that reports on the read concern level specified by transaction query operations performed after the database server last started.

readConcernCounters.transactionOps.none: Number of transaction query operations that did not specify a read concern level and instead used the default read concern level or the global default read or write concern configuration added with the setDefaultRWConcern command.

readConcernCounters.transactionOps.noneInfo: Information about the global default read concern and implicit-default read concern used by transaction query operations.

readConcernCounters.transactionOps.local: Number of transaction query operations that specified the "local" read concern level.

readConcernCounters.transactionOps.available: Number of transaction query operations that specified the "available" read concern level.

readConcernCounters.transactionOps.majority: Number of transaction query operations that specified the "majority" read concern level.

readConcernCounters.transactionOps.snapshot: Document containing transaction query operations that specified the "snapshot" read concern level.

readConcernCounters.transactionOps.snapshot.withClusterTime: Number of transaction query operations that specified the "snapshot" read concern level and the cluster time, which specified a point in time.

readConcernCounters.transactionOps.snapshot.withoutClusterTime: Number of transaction query operations that specified the "snapshot" read concern level without the cluster time, which means a point in time was omitted and the server will read the most recently committed snapshot available to the node.

repl

"repl" : {
   "hosts" : [
         <string>,
         <string>,
         <string>
   ],
   "setName" : <string>,
   "setVersion" : <num>,
   "isWritablePrimary" : <boolean>,
   "secondary" : <boolean>,
   "primary" : <hostname>,
   "me" : <hostname>,
   "electionId" : ObjectId(""),
   "primaryOnlyServices": {
      "ReshardingRecipientService": { "state": <string>, "numInstances": <num> },
      "RenameCollectionParticipantService": { "state": <string>, "numInstances": <num> },
      "ShardingDDLCoordinator": { "state": <string>, "numInstances": <num> },
      "ReshardingDonorService": { "state": <string>, "numInstances": <num> }
   },
   "rbid" : <num>,
   "replicationProgress" : [
         {
            "rid" : <ObjectId>,
            "optime" : { ts: <timestamp>, term: <num> },
            "host" : <hostname>,
            "memberId" : <num>
         },
        ...
   ]
}

repl: A document that reports on the replica set configuration. repl only appear when the current host is a replica set. See Replication for more information on replication.

repl.hosts: An array of the current replica set members' hostname and port information ("host:port").

repl.setName: A string with the name of the current replica set. This value reflects the --replSet command line argument, or replSetName value in the configuration file.

repl.isWritablePrimary: A boolean that indicates whether the current node is the primary of the replica set.

repl.secondary: A boolean that indicates whether the current node is a secondary member of the replica set.

repl.primary: The hostname and port information ("host:port") of the current primary member of the replica set.

repl.me: The hostname and port information ("host:port") for the current member of the replica set.

repl.primaryOnlyServices: Document that contains the number and status of instances of each primary service active on the server. Primary services can only start when a server is primary but can continue running to completion after the server changes state.
New in version 5.0.

repl.primaryOnlyServices.ReshardingRecipientService

Document that contains the state and number of instances of the ReshardingRecipientService.

Recipients are the shards,that would own the chunks after as a result of the resharding operation, according to the new shard key and zones.

The resharding coordinator instructs each donor and recipient shard primary, to rename the temporary sharded collection. The temporary collection becomes the new resharded collection.

New in version 5.0.

repl.primaryOnlyServices.RenameCollectionParticipantService

Document that contains the state and number of instances of the RenameCollectionParticipantService.

The RenameCollectionParticipantService ensures that, after a shard receives a renameCollection request, the shard is able to resume the local rename in case of system failure.

New in version 5.0.

repl.primaryOnlyServices.ShardingDDLCoordinator

Document that contains the state and number of instances of the ShardingDDLCoordinator.

The ShardingDDLCoordinator service manages DDL operations for primary databases such as: create database, drop database, renameCollection.

The ShardingDDLCoordinator ensures that one DDL operation for each database can happen at any one specific point in time within a sharded cluster.

New in version 5.0.

repl.primaryOnlyServices.ReshardingDonorService

Document that contains the state and number of instances of the ReshardingDonorService.

Donors are the shards that own chunks of the sharded collection before the rename operation completes.

The resharding coordinator instructs each donor and recipient shard primary, to rename the temporary sharded collection. The temporary collection becomes the new resharded collection.

New in version 5.0.

repl.rbid: Rollback identifier. Used to determine if a rollback has happened for this mongod instance.

repl.replicationProgress

An array with one document for each member of the replica set that reports replication process to this member. Typically this is the primary, or secondaries if using chained replication.

To include this output, you must pass the repl option to the serverStatus, as in the following:

db.serverStatus({ "repl": 1 })
db.runCommand({ "serverStatus": 1, "repl": 1 })

The content of the repl.replicationProgress section depends on the source of each member's replication. This section supports internal operation and is for internal and diagnostic use only.

repl.replicationProgress[n].rid: An ObjectId used as an ID for the members of the replica set. For internal use only.

repl.replicationProgress[n].optime: Information regarding the last operation from the oplog that the member applied, as reported from this member.

repl.replicationProgress[n].host: The name of the host in [hostname]:[port] format for the member of the replica set.

repl.replicationProgress[n].memberID: The integer identifier for this member of the replica set.

security

"security" : {
   "authentication" : {
      "saslSupportedMechsReceived" : <num>,
      "mechanisms" : {
         "MONGODB-X509" : {
            "speculativeAuthenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            },
            "authenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            }
         },
         "SCRAM-SHA-1" : {
            "speculativeAuthenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            },
            "authenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            }
         },
         "SCRAM-SHA-256" : {
            "speculativeAuthenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            },
            "authenticate" : {
               "received" : NumberLong(<num>),
               "successful" : NumberLong(<num>)
            }
          }
       }
     },
     "SSLServerSubjectName": <string>,
     "SSLServerHasCertificateAuthority": <boolean>,
     "SSLServerCertificateExpirationDate": <date>
},

security

A document that reports on:

The number of times a given authentication mechanism has been used to authenticate against the mongod or mongos instance. (New in MongoDB 4.4)
The mongod / mongos instance's TLS/SSL certificate. (Only appears for mongod or mongos instance with support for TLS)

security.authentication.saslSupportedMechsReceived: New in version 5.0.
The number of times a hello request includes a valid hello.saslSupportedMechs field.

security.authentication.mechanisms: A document that reports on the number of times a given authentication mechanism has been used to authenticate against the mongod or mongos instance. The values in the document distinguish standard authentication and speculative authentication. [1]
New in version 4.4.
Note
The fields in the mechanisms document depend on the configuration of the authenticationMechanisms parameter. The mechanisms document includes a field for each authentication mechanism supported by your mongod or mongos instance.
The following example shows the shape of the mechanisms document for a deployment that only supports x.509 authentication.

security.authentication.mechanisms.MONGODB-X509

A document that reports on the number of times x.509 has been used to authenticate against the mongod or mongos instance.

Includes total number of x.509 authentication attempts and the subset of those attempts which were speculative. [1]

New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.speculativeAuthenticate.received: Number of speculative authentication attempts received using x.509. Includes both successful and failed speculative authentication attempts. [1]
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.speculativeAuthenticate.successful: Number of successful speculative authentication attempts received using x.509. [1]
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.authenticate.received: Number of successful and failed authentication attempts received using x.509. This value includes speculative authentication attempts received using x.509.
New in version 4.4.

security.authentication.mechanisms.MONGODB-X509.authenticate.successful: Number of successful authentication attempts received using x.508. This value includes successful speculative authentication attempts which used x.509.
New in version 4.4.

[1]	(1, 2, 3, 4) Speculative authentication minimizes the number of network round trips during the authentication process to optimize performance.

security.SSLServerSubjectName: The subject name associated with the mongod / mongos instance's TLS/SSL certificate.

security.SSLServerHasCertificateAuthority

A boolean that is:

true when the mongod / mongos instance's TLS/SSL certificate is associated with a certificate authority.
false when the TLS/SSL certificate is self-signed.

security.SSLServerCertificateExpirationDate: The expiration date and time of the mongod / mongos instance's TLS/SSL certificate.

sharding

{
   "configsvrConnectionString" : "csRS/cfg1.example.net:27019,cfg2.example.net:27019,cfg2.example.net:27019",
   "lastSeenConfigServerOpTime" : {
      "ts" : <timestamp>,
      "t" : NumberLong(<num>)
   },
   "maxChunkSizeInBytes" : NumberLong(<num>)
}

sharding: A document with data regarding the sharded cluster. The lastSeenConfigServerOpTime is present only for a mongos or a shard member, not for a config server.

sharding.configsvrConnectionString: The connection string for the config servers.

sharding.lastSeenConfigServerOpTime

The latest optime of the CSRS primary that the mongos or the shard member has seen. The optime document includes:

ts, the Timestamp of the operation.
t, the term in which the operation was originally generated on the primary.

The lastSeenConfigServerOpTime is present only if the sharded cluster uses CSRS.

sharding.maxChunkSizeInBytes: The maximum size limit for a range to migrate. If this value has been updated recently on the config server, the maxChunkSizeInBytes may not reflect the most recent value.

shardingStatistics

When run on a member of a shard:

"shardingStatistics" : {
   "countStaleConfigErrors" : NumberLong(<num>),
   "countDonorMoveChunkStarted" : NumberLong(<num>),
   "totalDonorChunkCloneTimeMillis" : NumberLong(<num>),
   "totalCriticalSectionCommitTimeMillis" : NumberLong(<num>),
   "totalCriticalSectionTimeMillis" : NumberLong(<num>),
   "countDocsClonedOnRecipient" : NumberLong(<num>),
   "countDocsClonedOnDonor" : NumberLong(<num>),
   "countRecipientMoveChunkStarted" : NumberLong(<num>),
   "countDocsDeletedOnDonor" : NumberLong(<num>),
   "countDonorMoveChunkLockTimeout" : NumberLong(<num>),
   "unfinishedMigrationFromPreviousPrimary" : NumberLong(<num>),
   "catalogCache" : {
      "numDatabaseEntries" : NumberLong(<num>),
      "numCollectionEntries" : NumberLong(<num>),
      "countStaleConfigErrors" : NumberLong(<num>),
      "totalRefreshWaitTimeMicros" : NumberLong(<num>),
      "numActiveIncrementalRefreshes" : NumberLong(<num>),
      "countIncrementalRefreshesStarted" : NumberLong(<num>),
      "numActiveFullRefreshes" : NumberLong(<num>),
      "countFullRefreshesStarted" : NumberLong(<num>),
      "countFailedRefreshes" : NumberLong(<num>)
   },
   "rangeDeleterTasks" : <num>,
   "resharding" : {
      "countStarted" : NumberLong(1),
       "countSucceeded" : NumberLong(1),
       "countFailed" : NumberLong(0),
       "countCanceled" : NumberLong(0),
       "lastOpEndingChunkImbalance" : NumberLong(0),
       "active" : {
               "documentsCopied" : NumberLong(0),
               "bytesCopied" : NumberLong(0),
               "countWritesToStashCollections" : NumberLong(0),
               "countWritesDuringCriticalSection" : NumberLong(0),
               "countReadsDuringCriticalSection" : NumberLong(0),
               "oplogEntriesFetched" : NumberLong(0),
               "oplogEntriesApplied" : NumberLong(0),
               "insertsApplied" : NumberLong(0),
               "updatesApplied" : NumberLong(0),
               "deletesApplied" : NumberLong(0)
       },
       "oldestActive" : {
               "coordinatorAllShardsHighestRemainingOperationTimeEstimatedMillis" : NumberLong(0),
               "coordinatorAllShardsLowestRemainingOperationTimeEstimatedMillis" : NumberLong(0),
               "recipientRemainingOperationTimeEstimatedMillis" : NumberLong(0)
       },
       "latencies" : {
               "collectionCloningTotalRemoteBatchRetrievalTimeMillis" : NumberLong(0),
               "collectionCloningTotalRemoteBatchesRetrieved" : NumberLong(0),
               "collectionCloningTotalLocalInsertTimeMillis" : NumberLong(0),
               "collectionCloningTotalLocalInserts" : NumberLong(0),
               "oplogFetchingTotalRemoteBatchRetrievalTimeMillis" : NumberLong(0),
               "oplogFetchingTotalRemoteBatchesRetrieved" : NumberLong(0),
               "oplogFetchingTotalLocalInsertTimeMillis" : NumberLong(0),
               "oplogFetchingTotalLocalInserts" : NumberLong(0),
               "oplogApplyingTotalLocalBatchRetrievalTimeMillis" : NumberLong(0),
               "oplogApplyingTotalLocalBatchesRetrieved" : NumberLong(0),
               "oplogApplyingTotalLocalBatchApplyTimeMillis" : NumberLong(0),
               "oplogApplyingTotalLocalBatchesApplied" : NumberLong(0)
       },
       "currentInSteps" : {
               "countInstancesInCoordinatorState1Initializing" : NumberLong(0),
               "countInstancesInCoordinatorState2PreparingToDonate" : NumberLong(0),
               "countInstancesInCoordinatorState3Cloning" : NumberLong(0),
               "countInstancesInCoordinatorState4Applying" : NumberLong(0),
               "countInstancesInCoordinatorState5BlockingWrites" : NumberLong(0),
               "countInstancesInCoordinatorState6Aborting" : NumberLong(0),
               "countInstancesInCoordinatorState7Committing" : NumberLong(-1),
               "countInstancesInRecipientState1AwaitingFetchTimestamp" : NumberLong(0),
               "countInstancesInRecipientState2CreatingCollection" : NumberLong(0),
               "countInstancesInRecipientState3Cloning" : NumberLong(0),
               "countInstancesInRecipientState4Applying" : NumberLong(0),
               "countInstancesInRecipientState5Error" : NumberLong(0),
               "countInstancesInRecipientState6StrictConsistency" : NumberLong(0),
               "countInstancesInRecipientState7Done" : NumberLong(0),
               "countInstancesInDonorState1PreparingToDonate" : NumberLong(0),
               "countInstancesInDonorState2DonatingInitialData" : NumberLong(0),
               "countInstancesInDonorState3DonatingOplogEntries" : NumberLong(0),
               "countInstancesInDonorState4PreparingToBlockWrites" : NumberLong(0),
               "countInstancesInDonorState5Error" : NumberLong(0),
               "countInstancesInDonorState6BlockingWrites" : NumberLong(0),
               "countInstancesInDonorState7Done" : NumberLong(0)
       }
    }
   }
},

When run on a mongos:

"shardingStatistics" : {
   "numHostsTargeted": {
      "find" : {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "insert": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "update": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "delete": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               },
      "aggregate": {
         "allShards": NumberLong(<num>),
         "manyShards": NumberLong(<num>),
         "oneShard": NumberLong(<num>),
         "unsharded": NumberLong(<num>)
               }
      }
   },
   "catalogCache" : {
      "numDatabaseEntries" : NumberLong(<num>),
      "numCollectionEntries" : NumberLong(<num>),
      "countStaleConfigErrors" : NumberLong(<num>),
      "totalRefreshWaitTimeMicros" : NumberLong(<num>),
      "numActiveIncrementalRefreshes" : NumberLong(<num>),
      "countIncrementalRefreshesStarted" : NumberLong(<num>),
      "numActiveFullRefreshes" : NumberLong(<num>),
      "countFullRefreshesStarted" : NumberLong(<num>),
      "countFailedRefreshes" : NumberLong(<num>),
      "operationsBlockedByRefresh" : {
        "countAllOperations" : NumberLong(<num>),
        "countInserts" : NumberLong(<num>),
        "countQueries" : NumberLong(<num>),
        "countUpdates" : NumberLong(<num>),
        "countDeletes" : NumberLong(<num>),
        "countCommands" : NumberLong(<num>)
      }
   }
},
"rangeDeleterTasks: NumberLong(<num>),

shardingStatistics: A document which contains metrics on metadata refresh on sharded clusters.

shardingStatistics.countStaleConfigErrors

The total number of times that threads hit stale config exception. Since a stale config exception triggers a refresh of the metadata, this number is roughly proportional to the number of metadata refreshes.