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currentOp

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  • Definition
  • Compatibility
  • Syntax
  • Behavior
  • Access Control
  • Examples
  • Output Example
  • Specific Output Examples
  • Output Fields
currentOp

Deprecated since version 6.2.

In versions 6.2 and later use the $currentOp aggregation stage.

Returns a document that contains information on in-progress operations for the mongod instance.

Use the $currentOp aggregation stage instead of the currentOp command and its mongosh helper method db.currentOp().

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

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

Note

This command is supported in all MongoDB Atlas clusters. For information on all commands, see Unsupported Commands.

The command has the following syntax:

db.adminCommand(
{
currentOp: 1
}
)

Note

Starting in MongoDB 5.0, the $currentOp aggregation stage is used when running the helper method db.currentOp() with mongosh.

Given this, in the 5.0 version of the shell and with mongosh, db.currentOp() result sets are not subject to the 16MB BSON document return size document return size limit for documents of the previous legacy mongo versions.

currentOp must run against the admin database, and it can accept several optional fields.

Field
Description
"$ownOps"

Boolean. If set to true, returns information on the current user's operations only.

On mongod instances, users are always authorized to run currentOp with "$ownOps": true to view their own operations. See access control.

"$all"

Boolean. If set to true, returns information on all operations, including operations on idle connections and system operations.

"$all": true overrides any output field filters.

<filter>
Specify filter conditions on the Output Fields. See Examples.
comment

Optional. A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations:

A comment can be any valid BSON type (string, integer, object, array, etc).

New in version 4.4.

currentOp and the database profiler report the same basic diagnostic information for CRUD operations, including the following:

These operations are also included in the logging of slow queries (see slowOpThresholdMs for more information about slow query logging).

When using Queryable Encryption, currentOp operations with the encryptionInformation option redact certain information:

  • The output omits all fields after "command".

  • The output redacts "command" to include only the first element, $comment, and $db.

On systems running with authorization, the user must have access that includes the inprog privilege action.

Users can use $ownOps on mongod instances to view their own operations without the inprog privilege action.

db.adminCommand( { currentOp: 1, "$ownOps": 1 } )

Tip

See also:

The following examples use the currentOp command with various query documents to filter the output.

db.adminCommand(
{
currentOp: true,
"$all": true
}
)

The following example returns information on all write operations that are waiting for a lock:

db.adminCommand(
{
currentOp: true,
"waitingForLock" : true,
$or: [
{ "op" : { "$in" : [ "insert", "update", "remove" ] } },
{ "command.findandmodify": { $exists: true } }
]
}
)

The following example returns information on all active running operations that have never yielded:

db.adminCommand(
{
currentOp: true,
"active" : true,
"numYields" : 0,
"waitingForLock" : false
}
)

The following example returns information on all active operations for database db1 that have been running longer than 3 seconds:

db.adminCommand(
{
currentOp: true,
"active" : true,
"secs_running" : { "$gt" : 3 },
"ns" : /^db1\./
}
)

The following example returns information on index creation operations:

db.adminCommand(
{
currentOp: true,
$or: [
{ op: "command", "command.createIndexes": { $exists: true } },
{ op: "none", "msg" : /^Index Build/ }
]
}
)

These output samples illustrate currentOp output for particular operations. The fields that make up the actual output vary depending on the server's role.

{
type: "op",
desc: "Resharding{Donor, Recipient, Coordinator}Service <reshardingUUID>",
op: "command",
ns: "<database>.<collection>",
originatingCommand: {
reshardCollection: "<database>.<collection>",
key: <shardkey>,
unique: <boolean>,
collation: {locale: "simple"},
// Other options to the reshardCollection command are omitted
// to decrease the likelihood the output is truncated.
},
{donor, coordinator, recipient}State : "<service state>",
approxDocumentsToCopy: NumberLong(<count>),
approxBytesToCopy: NumberLong(<count>),
bytesCopied: NumberLong(<count>),
countWritesToStashCollections: NumberLong(<count>),
countWritesDuringCriticalSection : NumberLong(<count>),
countReadsDuringCriticalSection: NumberLong(<count>),
deletesApplied: NumberLong(<count>),
documentsCopied: NumberLong(<count>),
insertsApplied: NumberLong(<count>),
oplogEntriesFetched: NumberLong(<count>),
oplogEntriesApplied: NumberLong(<count>),
remainingOperationTimeEstimatedSecs: NumberLong(<count>),
allShardsLowestRemainingOperationTimeEstimatedSecs: NumberLong(<estimate>),
allShardsHighestRemainingOperationTimeEstimatedSecs: NumberLong(<estimate>),
totalApplyTimeElapsedSecs: NumberLong(<count>),
totalCopyTimeElapsedSecs: NumberLong(<count>),
totalCriticalSectionTimeElapsedSecs : NumberLong(<count>),
totalOperationTimeElapsedSecs: NumberLong(<count>),
updatesApplied: NumberLong(<count>),
}
{
type: "op",
desc: "GlobalIndex{Donor, Recipient, Coordinator}Service <globalIndexUUID}",
op: "command",
ns: "<database>.<collection>",
originatingCommand: {
createIndexes: "<database>.<collection>",
key: <indexkeypattern>,
unique: <boolean>,
<Additional createIndexes options>
},
{donor, coordinator, recipient}State : "<service state>",
approxDocumentsToScan: NumberLong(<count>),
approxBytesToScan: NumberLong(<count>),
bytesWrittenFromScan: NumberLong(<count>),
countWritesToStashCollections: NumberLong(<count>),
countWritesDuringCriticalSection : NumberLong(<count>),
countReadsDuringCriticalSection: NumberLong(<count>),
keysWrittenFromScan: NumberLong(<count>),
remainingOperationTimeEstimatedSecs: NumberLong(<count>),
allShardsLowestRemainingOperationTimeEstimatedSecs: NumberLong(<estimate>),
allShardsHighestRemainingOperationTimeEstimatedSecs: NumberLong(<estimate>),
totalCopyTimeElapsedSecs: NumberLong(<count>),
totalCriticalSectionTimeElapsedSecs : NumberLong(<count>),
totalOperationTimeElapsedSecs: NumberLong(<count>),
}
currentOp.type

The type of operation. Values are either:

  • op

  • idleSession

  • idleCursor

If the currentOp.type is op, currentOp.op provides details on the specific operation.

currentOp.host

The name of the host against which the operation is run.

currentOp.desc

A description of the client. This string includes the connectionId.

currentOp.connectionId

An identifier for the connection where the operation originated.

currentOp.client

A string with information about where the operation originated.

For multi-document transactions, client stores information about the most recent client to run an operation inside the transaction.

currentOp.appName

The identifier of the client application which ran the operation. Use the appName connection string option to set a custom value for the appName field.

currentOp.clientMetadata

Additional information on the client.

For multi-document transactions, client stores information about the most recent client to run an operation inside the transaction.

currentOp.currentOpTime

The start time of the operation.

currentOp.effectiveUsers

An array that contains a document for each user associated with the operation. Each user document contains the user name and the authentication db.

Tip

See also:

currentOp.runBy

An array that contains a document for each user who is impersonating the effectiveUser(s) for the operation. The runBy document contains the user name and the authentication db. In general, the runBy user is the __system user; e.g.

"runBy" : [
{
"user" : "__system",
"db" : "local"
}
]

Only available on sharded clusters

currentOp.lsid

The session identifier.

Only present if the operation is associated with a session.

currentOp.transaction

A document that contains multi-document transaction information.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.parameters

A document that contains information on multi-document transaction.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.parameters.txnNumber

The transaction number.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.parameters.autocommit

A boolean flag that indicates if autocommit is on for the transaction.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.parameters.readConcern

The read concern for the transaction.

Multi-document transactions support read concern "snapshot", "local", and "majority".

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.readTimestamp

The timestamp of the snapshot being read by the operations in the transaction.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.startWallClockTime

The date and time (with time zone) of the transaction start.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.timeOpenMicros

The duration of the transaction in microseconds.

The timeActiveMicros value added to the timeInactiveMicros should equal the timeOpenMicros.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.timeActiveMicros

The total amount of time that the transaction has been active; i.e. when the transaction had operations running.

The timeActiveMicros value added to the timeInactiveMicros should equal the timeOpenMicros.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.timeInactiveMicros

The total amount of time that the transaction has been inactive; i.e. when the transaction had no operations running.

The timeInactiveMicros value added to the timeActiveMicros should equal the timeOpenMicros.

Only present if the operation is part of a multi-document transaction.

currentOp.transaction.expiryTime

The date and time (with time zone) when the transaction will time out and abort.

The currentOp.transaction.expiryTime equals the currentOp.transaction.startWallClockTime + the transactionLifetimeLimitSeconds.

For more information, see Runtime Limit for transactions.

Only present if the operation is part of a multi-document transaction.

currentOp.twoPhaseCommitCoordinator

Information on either:

  • The commit coordination metrics for a transaction whose write operations span multiple shards.

    Commit coordination is handled by a shard, and currentOp (run either on a mongos or a shard member) returns a shard's coordination information only for those transactions currently being coordinated by that shard.

    To filter for just the commit coordination metrics:

    db.currentOp( { desc: "transaction coordinator" })
  • A specific commit coordination operation (i.e. currentOp.type is op and currentOp.desc is "TransactionCoordinator") spawned by the transaction coordinator.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.lsid

The session identifier for the multi-shard transaction.

The combination of the lsid and txnNumber identifies the transaction.

Available for both the commit coordination metrics and for specific coordination operation.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.txnNumber

The transaction number for the multi-shard transaction.

The combination of the txnNumber and lsid identifies the transaction.

Available for both the commit coordination metrics and for specific coordination operation.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.action

The specific commit coordination operation spawned by the transaction coordinator:

  • "sendingPrepare"

  • "sendingCommit"

  • "sendingAbort"

  • "writingParticipantList"

  • "writingDecision"

  • "deletingCoordinatorDoc"

Only available for specific coordination operation.

currentOp.twoPhaseCommitCoordinator.startTime

The start date and time of the action.

Only available for specific coordination operation.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.numParticipants

Number of shards participating in this commit.

Only available for the commit coordination metrics.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.state

The current step/state of the commit coordination process.

Step/stage
Description
inactive
Not actively part of a commit.
writingParticipantList
Writing a local record of the list of shards that are part of this multi-shard transaction.
waitingForVotes
Waiting for the participants to respond with vote to commit or abort.
writingDecision
Writing a local record of the coordinator's decision to commit or abort based on votes.
waitingForDecisionAck
Waiting for participants to acknowledge the coordinator's decision to commit or abort.
deletingCoordinatorDoc
Deleting the local record of commit decision.

Only available for the commit coordination metrics.

See also currentOp.twoPhaseCommitCoordinator.stepDurations.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.commitStartTime

The date and time when the commit started.

Only available for the commit coordination metrics.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.hasRecoveredFromFailover

A boolean that indicates whether the commit coordination was restarted due to failover on the shard that is coordinating the commit.

If hasRecoveredFromFailover is true, then the times specified in currentOp.twoPhaseCommitCoordinator.stepDurations may not be accurate for all steps.

Only available for the commit coordination metrics.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.stepDurations

A document that contains the duration, in microseconds, of the commit coordination steps/state completed or in progress:

"stepDurations" : {
"writingParticipantListMicros" : NumberLong(17801),
"totalCommitDurationMicros" : NumberLong(42488463),
"waitingForVotesMicros" : NumberLong(30378502),
"writingDecisionMicros" : NumberLong(15015),
"waitingForDecisionAcksMicros" : NumberLong(12077145),
"deletingCoordinatorDocMicros" : NumberLong(6009)
},

If currentOp.twoPhaseCommitCoordinator.hasRecoveredFromFailover is true, then the times specified in stepDurations may not be accurate for all steps.

For a coordinator in an inactive state, the document is empty:

"stepDurations" : {
}

Only available for the commit coordination metrics.

See currentOp.twoPhaseCommitCoordinator.state.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.decision

A document that contains the commit/abort decision, for example:

  • For a commit decision:

    "decision" : {
    "decision" : "commit",
    "commitTimestamp" : Timestamp(1572034669, 3)
    }
  • For an abort decision:

    "decision" : {
    "decision" : "abort",
    "abortStatus" : {
    "code" : 282,
    "codeName" : "TransactionCoordinatorReachedAbortDecision",
    "errmsg" : "Transaction exceeded deadline"
    }
    }

Only available for the commit coordination metrics.

New in version 4.2.1.

currentOp.twoPhaseCommitCoordinator.deadline

The date and time by which the commit must finish.

Only available for the commit coordination metrics.

New in version 4.2.1.

currentOp.opid

The identifier for the operation. You can pass this value to db.killOp() in mongosh to terminate the operation.

Warning

Terminate running operations with extreme caution. Only use db.killOp() to terminate operations initiated by clients and do not terminate internal database operations.

currentOp.active

A boolean value specifying whether the operation has started. Value is true if the operation has started or false if the operation is idle, such as an idle connection or an internal thread that is currently idle. An operation can be active even if the operation has yielded to another operation. For some inactive background threads, such as an inactive signalProcessingThread, MongoDB suppresses various empty fields.

currentOp.secs_running

The duration of the operation in seconds. MongoDB calculates this value by subtracting the current time from the start time of the operation.

Only appears if the operation is running; i.e. if active is true.

currentOp.microsecs_running

The duration of the operation in microseconds. MongoDB calculates this value by subtracting the current time from the start time of the operation.

Only appears if the operation is running; i.e. if active is true.

currentOp.op

A string that identifies the specific operation type. Only present if currentOp.type is op.

The possible values are:

  • "none"

  • "update"

  • "insert"

  • "query"

  • "command"

  • "getmore"

  • "remove"

  • "killcursors"

"query" operations include read operations.

"command" operations include most commands such as the createIndexes and findAndModify.

currentOp.ns

The namespace the operation targets. A namespace consists of the database name and the collection name concatenated with a dot (.); that is, "<database>.<collection>".

currentOp.command

A document containing the full command object associated with this operation.

For example, the following output contains the command object for a find operation on a collection named items in a database named test:

"command" : {
"find" : "items",
"filter" : {
"sku" : 1403978
},
...
"$db" : "test"
}

The following example output contains the command object for a getMore operation generated by a command with cursor ID 19234103609 on a collection named items in a database named test:

"command" : {
"getMore" : NumberLong("19234103609"),
"collection" : "items",
"batchSize" : 10,
...
"$db" : "test"
},

If the command document exceeds 1 kilobyte, the document has the following form:

"command" : {
"$truncated": <string>,
"comment": <string>
}

The $truncated field contains a string summary of the document excluding the document's comment field if present. If the summary still exceeds 1 kilobyte then it is further truncated, denoted by an ellipsis (...) at the end of the string.

The comment field is present if a comment was passed to the operation. Starting in MongoDB 4.4, a comment may be attached to any database command.

currentOp.planSummary

Specifies whether the cursor uses a collection scan (COLLSCAN) or an index scan (IXSCAN { ... }).

The IXSCAN also includes the specification document of the index used.

currentOp.prepareReadConflicts

The number of times the current operation had to wait for a prepared transaction with a write to commit or abort.

While waiting, the current operation continues to hold any necessary locks and storage engine resources.

currentOp.writeConflicts

The number of times the current operation conflicted with another write operation on the same document.

currentOp.cursor

A document that contains the cursor information for getmore operations; i.e. where op is getmore.

If reporting on a getmore operation before the getmore has accessed its cursor information, the cursor field is not available.

currentOp.cursor.cursorId

The ID of the cursor.

currentOp.cursor.createdDate

The date and time when the cursor was created.

currentOp.cursor.lastAccessDate

The date and time when the cursor was last used.

currentOp.cursor.nDocsReturned

The cumulative number of documents returned by the cursor.

currentOp.cursor.nBatchesReturned

The cumulative number of batches returned by the cursor.

currentOp.cursor.noCursorTimeout

The flag that indicates that the cursor will not timeout when idle; i.e. if the cursor has the noTimeout option set.

  • If true, the cursor does not time out when idle.

  • If false, the cursor times out when idle.

Tip

currentOp.cursor.tailable

The flag that indicates if the cursor is a tailable cursor for a capped collection. Tailable cursors remain open after the client exhausts the results in the initial cursor.

currentOp.cursor.awaitData

The flag that indicates whether the tailable cursor should temporarily block a getMore command on the cursor while waiting for new data rather than returning no data.

For non-tailable cursors, the value is always false.

currentOp.cursor.originatingCommand

The originatingCommand field contains the full command object (e.g. find or aggregate) which originally created the cursor.

currentOp.cursor.planSummary

Specifies whether the cursor uses a collection scan (COLLSCAN) or an index scan (IXSCAN { ... }).

The IXSCAN also includes the specification document of the index used.

currentOp.cursor.operationUsingCursorId

The opid of the operation using the cursor.

Only present if the cursor is not idle.

currentOp.locks

The locks document reports the type and mode of locks the operation currently holds. The possible lock types are as follows:

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.
DDLDatabase

Represents a DDL database lock.

New in version 7.1.

DDLCollection

Represents a DDL collection lock.

New in version 7.1.

oplog
Represents lock on the oplog.

The possible modes are as follows:

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.
currentOp.admissionPriority

For internal use. The value is the priority an operation has when it tries to acquire a ticket in order to perform a storage engine action.

Possible values are: "low", "normal", and "immediate". Only operations with a "low" value are reported.

Sample currentOp output:

{
type: 'op',
host: 'ip-10-122-5-147:27017',
desc: 'JournalFlusher',
active: true,
currentOpTime: '2022-10-11T12:45:52.053+00:00',
opid: 201,
op: 'none',
ns: '',
command: {},
numYields: 0,
admissionPriority: 'low',
locks: {},
waitingForLock: false,
lockStats: {},
waitingForFlowControl: false,
flowControlStats: {}
}

The admissionPriority value is also reported in the slow log.

New in version 6.3.

currentOp.waitingForLock

Returns a boolean value. waitingForLock is true if the operation is waiting for a lock and false if the operation has the required lock.

currentOp.msg

The msg provides a message that describes the status and progress of the operation. In the case of indexing or mapReduce operations, the field reports the completion percentage.

currentOp.progress

Reports on the progress of mapReduce or indexing operations. The progress fields corresponds to the completion percentage in the msg field. The progress specifies the following information:

currentOp.progress.done

Reports the number completed.

currentOp.progress.total

Reports the total number.

currentOp.killPending

Returns true if the operation is currently flagged for termination. When the operation encounters its next safe termination point, the operation will terminate.

currentOp.numYields

numYields is a counter that reports the number of times the operation has yielded to allow other operations to complete.

Typically, operations yield when they need access to data that MongoDB has not yet fully read into memory. This allows other operations that have data in memory to complete quickly while MongoDB reads in data for the yielding operation.

currentOp.dataThroughputLastSecond

Amount of data (in MiB) processed by the validate operation in the last second. Only available for a validate operation that is currently scanning documents. For example:

"msg" : "Validate: scanning documents Validate: scanning documents: 7258/24000 30%",
"progress" : {
"done" : 7258,
"total" : 24000
},
"numYields" : 0,
"dataThroughputLastSecond" : 15.576952934265137,
"dataThroughputAverage" : 15.375944137573242,

New in version 4.4.

currentOp.dataThroughputAverage

The average amount of data (in MiB) processed by the validate operation. Only available for a validate operation that is currently scanning documents. For example:

"msg" : "Validate: scanning documents Validate: scanning documents: 7258/24000 30%",
"progress" : {
"done" : 7258,
"total" : 24000
},
"numYields" : 0,
"dataThroughputLastSecond" : 15.576952934265137,
"dataThroughputAverage" : 15.375944137573242,

New in version 4.4.

currentOp.fsyncLock

Specifies if database is currently locked for fsync write/snapshot.

Only appears if locked; i.e. if fsyncLock is true.

currentOp.info

Information regarding how to unlock database from db.fsyncLock(). Only appears if fsyncLock is true.

currentOp.lockStats

For each lock type and mode (see currentOp.locks for descriptions of lock types and modes), returns the following information:

currentOp.lockStats.acquireCount

Number of times the operation acquired the lock in the specified mode.

currentOp.lockStats.acquireWaitCount

Number of times the operation had to wait for the acquireCount lock acquisitions because the locks were held in a conflicting mode. acquireWaitCount is less than or equal to acquireCount.

currentOp.lockStats.timeAcquiringMicros

Cumulative time in microseconds that the operation had to wait to acquire the locks.

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

currentOp.lockStats.deadlockCount

Number of times the operation encountered deadlocks while waiting for lock acquisitions.

currentOp.waitingForFlowControl

A boolean that indicates if the operation is in the process of waiting for flow control.

currentOp.flowControlStats

The flow control statistics for this operation.

currentOp.flowControlStats.acquireCount

The number of times this operation acquired a ticket.

currentOp.flowControlStats.acquireWaitCount

The number of times this operation waited to acquire a ticket.

currentOp.flowControlStats.timeAcquiringMicros

The total time this operation has waited to acquire a ticket.

currentOp.totalOperationTimeElapsedSecs

The total time elapsed, in seconds, for the current resharding operation. The time is set to 0 when a new resharding operation starts.

Only present if a resharding operation is taking place.

New in version 5.0.

Starting in MongoDB 6.1, this metric is also available on the coordinator during resharding.

currentOp.updatesApplied

The number of updates applied.

Only present on a recipient shard when a resharding operation is taking place.

New in version 6.1.

currentOp.remainingOperationTimeEstimatedSecs

remainingOperationTimeEstimatedSecs: estimated time remaining in seconds for the current resharding operation. It is returned as -1 when a new resharding operation starts.

Starting in:

  • MongoDB 5.0, but before MongoDB 6.1, remainingOperationTimeEstimatedSecs is only available on a recipient shard during a resharding operation.

  • MongoDB 6.1, remainingOperationTimeEstimatedSecs is also available on the coordinator during a resharding operation.

The resharding operation performs these phases in order:

  1. The clone phase duplicates the current collection data.

  2. The catch-up phase applies any pending write operations to the resharded collection.

remainingOperationTimeEstimatedSecs is set to a pessimistic time estimate:

  • The catch-up phase time estimate is set to the clone phase time, which is a relatively long time.

  • In practice, if there are only a few pending write operations, the actual catch-up phase time is relatively short.

New in version 5.0.

currentOp.allShardsLowestRemainingOperationTimeEstimatedSecs

Calculated across all shards, the lowest estimate of the number of seconds remaining.

Only present on a coordinator when a resharding operation is taking place.

New in version 6.1.

currentOp.allShardsHighestRemainingOperationTimeEstimatedSecs

Calculated across all shards, the highest estimate of the number of seconds remaining.

Only present on a coordinator when a resharding operation is taking place.

New in version 6.1.

currentOp.approxDocumentsToCopy

The approximate number of documents to be copied from the donor shards to the recipient shards during the resharding operation. This number is an estimate that is set at the beginning of the resharding operation and does not change after it has been set. The number is set to 0 when a new resharding operation starts. It is possible for $currentOp.documentsCopied and $currentOp.bytesCopied to end up exceeding $currentOp.approxDocumentsToCopy and $currentOp.approxBytesToCopy, respectively, if the post-resharding data distribution is not perfectly uniform.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.documentsCopied

The number of documents copied form donor shards to recipient shards during the resharding operation. The number is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.approxBytesToCopy

The approximate number of bytes to be copied from the donor shards to the recipient shards during the resharding operation. This number is an estimate that is set at the beginning of the resharding operation and does not change after it has been set. The number is set to 0 when a new resharding operation starts. It is possible for $currentOp.documentsCopied and $currentOp.bytesCopied to end up exceeding $currentOp.approxDocumentsToCopy and $currentOp.approxBytesToCopy, respectively, if the post-resharding data distribution is not perfectly uniform.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.bytesCopied

The number of bytes copied from donor shards to recipient shards during the resharding operation. The number is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.countWritesToStashCollections

The number of writes to the recipient stash collections.

Only present on a recipient shard when a resharding operation is taking place.

New in version 6.1.

currentOp.countWritesDuringCriticalSection

The number of writes attempted during the donor's critical section.

Only present on a donor shard when a resharding operation is taking place.

New in version 6.1.

currentOp.countReadsDuringCriticalSection

The number of reads attempted during the donor's critical section.

Only present on a donor shard when a resharding operation is taking place.

New in version 6.1.

currentOp.deletesApplied

The number of deletes applied to the temporary resharding collection. Each oplog entry that involves a delete increments the counter by 1.

Only present on a recipient shard when a resharding operation is taking place.

New in version 6.1.

currentOp.insertsApplied

The number of inserts applied to the temporary resharding collection. Each oplog entry that involves an insert increments the counter by 1.

Only present on a recipient shard when a resharding operation is taking place.

New in version 6.1.

currentOp.totalCopyTimeElapsedSecs

The total elapsed time, in seconds, for ongoing data copy tasks from donor shards to recipient shards for the current resharding operation. The time is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

Starting in MongoDB 6.1, this metric is also available on the coordinator during resharding.

currentOp.oplogEntriesFetched

The number of entries fetched from the oplog for the current resharding operation. The number is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.oplogEntriesApplied

The number of entries applied to the oplog for the current resharding operation. The number is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

currentOp.totalApplyTimeElapsedSecs

The total elapsed time, in seconds, for the apply step of the current resharding operation. In the apply step, recipient shards apply oplog entries to modify their data based on new incoming writes from donor shards. The time is set to 0 when a new resharding operation starts.

Only present on a recipient shard when a resharding operation is taking place.

New in version 5.0.

Starting in MongoDB 6.1, this metric is also available on the coordinator during resharding.

currentOp.countWritesDuringCriticalSection

The number of writes performed in the critical section for the current resharding operation. The critical section prevents new incoming writes to the collection currently being resharded. The number is set to 0 when a new resharding operation starts.

Only present on a donor shard when a resharding operation is taking place.

New in version 5.0.

currentOp.totalCriticalSectionTimeElapsedSecs

The total elapsed time, in seconds, for the critical section of the current resharding operation. The critical section prevents new incoming writes to the collection currently being resharded. The time is set to 0 when a new resharding operation starts.

Only present on a donor shard when a resharding operation is taking place.

New in version 5.0.

Starting in MongoDB 6.1, this metric is also available on the coordinator during resharding.

currentOp.donorState

The current state of a donor shard for the resharding operation. The state is set to unused when a new resharding operation starts.

Only present on a donor shard when a resharding operation is taking place.

State
Description
unused
The resharding operation is about to start or recovering from a primary failover.
preparing-to-donate
The donor shard is preparing to donate data to the recipient shards.
donating-initial-data
The donor shard is donating data to the recipient shards.
donating-oplog-entries
The donor shard is donating oplog entries to the recipient shards.
preparing-to-block-writes
The donor shard is about to prevent new incoming write operations to the collection that is being resharded.
error
An error occurred during the resharding operation.
blocking-writes
The donor shard is preventing new incoming write operations and the donor shard has notified all recipient shards that new incoming writes are prevented.
done
The donor shard has dropped the old sharded collection and the resharding operation is complete.

New in version 5.0.

currentOp.recipientState

The current state of a recipient shard for a resharding operation. The state is set to unused when a new resharding operation starts.

Only present on a donor shard when a resharding operation is taking place.

State
Description
unused
The resharding operation is about to start or recovering from a primary failover.
awaiting-fetch-timestamp
The recipient shard is waiting for the donor shards to be prepared to donate their data.
creating-collection
The recipient shard is creating the new sharded collection.
cloning
The recipient shard is receiving data from the donor shards.
applying
The recipient shard is applying oplog entries to modify its copy of the data based on the new incoming writes from donor shards.
error
An error occurred during the resharding operation.
strict-consistency
The recipient shard has all data changes stored in a temporary collection.
done
The resharding operation is complete.

New in version 5.0.

currentOp.coordinatorState

The state of the resharding coordinator for the current resharding operation. The resharding coordinator is an operation that runs on the config server primary. The state is set to unused when a new resharding operation starts.

Only present on the coordinating config server.

State
Description
unused
The resharding operation is about to start or recovering from a primary failover.
initializing
The resharding coordinator has inserted the coordinator document into config.reshardingOperations and has added the reshardingFields to the config.collections entry for the original collection.
preparing-to-donate

The resharding coordinator

  • has created a config.collections entry for the temporary resharding collection.

  • has inserted entries into config.chunks for ranges based on the new shard key.

  • has inserted entries into config.tags for any zones associated with the new shard key.

The coordinator informs participant shards to begin the resharding operation. The coordinator then waits until all donor shards have picked a minFetchTimestamp and are ready to donate.

cloning
The resharding coordinator informs donor shards to donate data to recipient shards. The coordinator waits for all recipients to finish cloning the data from the donor.
applying
The resharding coordinator informs recipient shards to modify their copies of data based on new incoming writes from donor shards. The coordinator waits for all recipients to finish applying oplog entries.
blocking-writes
The resharding coordinator informs donor shards to prevent new incoming write operations to the collection being resharded. The coordinator then waits for all recipients to have all data changes.
aborting
An unrecoverable error occurred during the resharding operation or the abortReshardCollection command (or the sh.abortReshardCollection() method) was run.
committing
The resharding coordinator removes the config.collections entry for the temporary resharding collection. The coordinator then adds the recipientFields to the source collection's entry.

New in version 5.0.

currentOp.opStatus

This metric is removed in version 6.1. For a list of new metrics that replace and expand the reporting currentOp.opStatus provided, see the release notes.

Changed in version 6.1.

currentOp.collUuid

The UUID of the sampled collection.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.startTime

The time at which query sampling began.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.samplesPerSecond

The maximum number of queries to sample per second.

On a sharded cluster, this is reported on mongos instead of mongod. On a replica set, this is reported on mongod.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.sampledReadsCount

The number of sampled read queries.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.sampledWritesCount

The number of sampled write queries.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.sampledReadsBytes

The size of the sampled read queries, in bytes.

On a replica set, this is reported on every mongod.

On a sharded cluster, this only reported on mongod with --shardsvr.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

currentOp.sampledWritesBytes

The size of the sampled write queries, in bytes.

On a replica set, this is reported on every mongod.

On a sharded cluster, this only reported on mongod with --shardsvr.

This field only appears on documents related to query sampling. For details, see Sampled Queries.

New in version 7.0.

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