$currentOp (aggregation)
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Definition
$currentOp
Returns a stream of documents containing information on active and/or dormant operations as well as inactive sessions that are holding locks as part of a transaction. The stage returns a document for each operation or session. To run
$currentOp
, use thedb.aggregate()
helper on theadmin
database.The
$currentOp
aggregation stage is preferred over thecurrentOp
command and itsmongosh
helper methoddb.currentOp()
. Because thecurrentOp
command anddb.currentOp()
helper method return the results in a single document, the total size of thecurrentOp
result set is subject to the maximum 16MB BSON size limit for documents. The$currentOp
stage returns a cursor over a stream of documents, each of which reports a single operation. Each operation document is subject to the 16MB BSON limit, but unlike thecurrentOp
command, there is no limit on the overall size of the result set.$currentOp
also enables you to perform arbitrary transformations of the results as the documents pass through the pipeline.
Syntax
{ $currentOp: { allUsers: <boolean>, idleConnections: <boolean>, idleCursors: <boolean>, idleSessions: <boolean>, localOps: <boolean> } }
$currentOp
takes an options document as its operand:
Option | Description |
---|---|
Boolean.
For standalone and replica sets that enforce access control, For sharded clusters that enforce access control, the Defaults to | |
Boolean. If set to Defaults to | |
Boolean. If set to Information on idle cursors have the Information on cursors currently active in a
Defaults to | |
Boolean.
Defaults to | |
Boolean. If set to The Defaults to | |
Boolean. Determines whether callstack information is returned as
part of the
Defaults to |
Omitting any of the above parameters causes $currentOp to use that parameter's default value. Specify an empty document, as shown below, to use the default values of all parameters.
{ $currentOp: { } }
Constraints
Pipeline
$currentOp
must be the first stage in the pipeline.Pipelines that start with
$currentOp
can only be run on theadmin
database.
Access Control
For standalone and replica sets that enforce access control,
inprog
privilege is required to run$currentOp
if allUsers: true.For sharded clusters that enforce access control, the
inprog
privilege is required to run$currentOp
.
Transactions
$currentOp
is not allowed in transactions.
Redaction
When using Queryable Encryption,
$currentOp
output redacts certain information:
The output omits all fields after
"command"
.The output redacts
"command"
to include only the first element,$comment
, and$db
.
Examples
The following examples show how to use the $currentOp
aggregation
stage.
Inactive Sessions
This example returns information on inactive sessions that are holding locks as part of a transaction. Specifically:
The first stage returns documents for all active operations as well as inactive sessions that are holding locks as part of a transaction.
The second stage filters for documents related to inactive sessions that are holding locks as part of a transaction.
db.getSiblingDB("admin").aggregate( [ { $currentOp : { allUsers: true, idleSessions: true } }, { $match : { active: false, transaction : { $exists: true } } } ] )
You can use $currentOp.type
to specify
an equivalent filter:
db.getSiblingDB("admin").aggregate( [ { $currentOp : { allUsers: true, idleSessions: true } }, { $match : { type: "idleSession" } } ] )
Tip
For transactions on a sharded cluster, include localOps:true in the previous examples for a composite view of the transactions.
Both operations return documents of the form:
When run on a mongod
that is part of a replica set:
{ "type" : "idleSession", "host" : "example.mongodb.com:27017", "desc" : "inactive transaction", "client" : "198.51.100.1:50428", "connectionId" : NumberLong(32), "appName" : "", "clientMetadata" : { "driver" : { "name" : "PyMongo", "version" : "3.9.0" }, "os" : { "type" : "Darwin", "name" : "Darwin", "architecture" : "x86_64", "version" : "10.14.5" }, "platform" : "CPython 3.7.1.final.0" }, "lsid" : { "id" : UUID("ff21e1a9-a130-4fe0-942f-9e6b6c67ea3c"), "uid" : BinData(0,"3pxqkATNUYKV/soT7qqKE0zC0BFb0pBz1pk4xXcSHsI=") }, "transaction" : { "parameters" : { "txnNumber" : NumberLong(4), "autocommit" : false, "readConcern" : { "level" : "snapshot", "afterClusterTime" : Timestamp(1563892246, 1) } }, "readTimestamp" : Timestamp(0, 0), "startWallClockTime" : "2019-07-23T10:30:49.461-04:00", "timeOpenMicros" : NumberLong(1913590), "timeActiveMicros" : NumberLong(55), "timeInactiveMicros" : NumberLong(1913535), "expiryTime" : "2019-07-23T10:31:49.461-04:00" }, "waitingForLock" : false, "active" : false, "locks" : { "ReplicationStateTransition" : "w", "Global" : "w", "Database" : "w", "Collection" : "w" }, "lockStats" : { "ReplicationStateTransition" : { "acquireCount" : { "w" : NumberLong(5) } }, "Global" : { "acquireCount" : { "r" : NumberLong(3), "w" : NumberLong(1) } }, "Database" : { "acquireCount" : { "r" : NumberLong(2), "w" : NumberLong(1) } }, "Collection" : { "acquireCount" : { "w" : NumberLong(1) } }, "Mutex" : { "acquireCount" : { "r" : NumberLong(3) } }, "oplog" : { "acquireCount" : { "r" : NumberLong(2) } } }, "waitingForFlowControl" : false, "flowControlStats" : {}, }
Running $currentOp
with
localOps:true provides a
composite view (rather than per shard information) of the
in-progress transactions run on that mongos
.
db.getSiblingDB("admin").aggregate( [ { $currentOp : { allUsers: true, idleSessions: true, localOps: true } }, { $match : { type: "idleSession" } } ] ); // or db.getSiblingDB("admin").aggregate( [ { $currentOp : { allUsers: true, idleSessions: true, localOps: true } }, { $match : { active: false, transaction : { $exists: true } } } ] )
{ "type" : "idleSession", "host" : "example.mongodb.com:27017", "desc" : "inactive transaction", "client" : "198.51.100.1:49618", "connectionId" : NumberLong(48), "appName" : "", "clientMetadata" : { "driver" : { "name" : "PyMongo", "version" : "3.9.0" }, "os" : { "type" : "Darwin", "name" : "Darwin", "architecture" : "x86_64", "version" : "10.14.6" }, "platform" : "CPython 3.7.1.final.0", "mongos" : { "host" : "example.mongodb.com:27017", "client" : "198.51.100.1:53268", "version" : "4.2.1" } }, "lsid" : { "id" : UUID("2c9ce111-133e-45b7-a00f-a7871005cae1"), "uid" : BinData(0,"3pxqkATNUYKV/soT7qqKE0zC0BFb0pBz1pk4xXcSHsI=") }, "active" : false, "transaction" : { "parameters" : { "txnNumber" : NumberLong(2), "autocommit" : false, "readConcern" : { "level" : "snapshot", "afterClusterTime" : Timestamp(1571869019, 2) } }, "globalReadTimestamp" : Timestamp(1571869019, 2), "startWallClockTime" : "2019-10-23T18:16:59.341-04:00", "timeOpenMicros" : NumberLong(169244639), "timeActiveMicros" : NumberLong(535), "timeInactiveMicros" : NumberLong(169244104), "numParticipants" : 2, "participants" : [ { "name" : "shardB", "coordinator" : true, "readOnly" : false }, { "name" : "shardA", "coordinator" : false, "readOnly" : false } ], "numReadOnlyParticipants" : 0, "numNonReadOnlyParticipants" : 2 } }
When run without localOps:true on
the mongos
, the transaction information is per
shard.
When run on a mongos
without localOps:true, the transaction information is per
shard.
{ "shard" : "shardB", "type" : "idleSession", "host" : "shardB.mongodb.com:27018", "desc" : "inactive transaction", "client_s" : "198.51.100.1:53961", "connectionId" : NumberLong(63), "appName" : "", "clientMetadata" : { "driver" : { "name" : "PyMongo", "version" : "3.9.0" }, "os" : { "type" : "Darwin", "name" : "Darwin", "architecture" : "x86_64", "version" : "10.14.6" }, "platform" : "CPython 3.7.1.final.0", "mongos" : { "host" : "example.mongodb.com:27017", "client" : "198.51.100.1:53976", "version" : "4.2.0" } }, "lsid" : { "id" : UUID("720d403c-8daf-40bb-b61e-329e20b0493b"), "uid" : BinData(0,"3pxqkATNUYKV/soT7qqKE0zC0BFb0pBz1pk4xXcSHsI=") }, "transaction" : { "parameters" : { "txnNumber" : NumberLong(1), "autocommit" : false, "readConcern" : { "level" : "snapshot" } }, "readTimestamp" : Timestamp(0, 0), "startWallClockTime" : "2019-10-21T18:31:12.192-04:00", "timeOpenMicros" : NumberLong(24137008), "timeActiveMicros" : NumberLong(52), "timeInactiveMicros" : NumberLong(24136956), "expiryTime" : "2019-10-21T18:32:12.192-04:00" }, "waitingForLock" : false, "active" : false, "locks" : { "ReplicationStateTransition" : "w", "Global" : "w", "Database" : "w", "Collection" : "w" }, "lockStats" : { "ReplicationStateTransition" : { "acquireCount" : { "w" : NumberLong(3) } }, "Global" : { "acquireCount" : { "r" : NumberLong(1), "w" : NumberLong(1) } }, "Database" : { "acquireCount" : { "r" : NumberLong(1), "w" : NumberLong(1) } }, "Collection" : { "acquireCount" : { "r" : NumberLong(1), "w" : NumberLong(1) } }, "Mutex" : { "acquireCount" : { "r" : NumberLong(6) } } } } { "shard" : "shardA", "type" : "idleSession", ... }
Sampled Queries
This example returns information on query sampling progess.
The first stage returns documents for all active operations.
The second stage filters for documents related to the query analyzer.
db.getSiblingDB("admin").aggregate( [ { $currentOp: { allUsers: true, localOps: true } }, { $match: { desc: "query analyzer" } } ] )
This pipeline returns output similar to the following:
When run on a mongod
that is part of a replica set:
{ "desc" : "query analyzer", "ns" : "testDb.testColl", "collUuid" : UUID("ed9dfb1d-5b7c-4c6b-82e9-b0f537335795"), "samplesPerSecond" : 5, "startTime" : ISODate("2023-08-08T16:23:22.846Z"), "sampledReadsCount" : NumberLong(2), "sampledReadsBytes" : NumberLong(346), "sampledWritesCount" : NumberLong(3), "sampledWritesBytes" : NumberLong(904) }
When run on a mongos
that is part of a sharded cluster:
{ "desc" : "query analyzer", "ns" : "testDb.testColl", "collUuid" : UUID("5130b4df-5966-434f-85f0-f8956b5ca74e"), "samplesPerSecond" : 5, "startTime" : ISODate("2023-08-08T16:15:07.427Z"), "sampledReadsCount" : NumberLong(2), "sampledWritesCount" : NumberLong(3) }
When run on a mongod --shardsvr
that is part of a sharded
cluster:
{ "desc" : "query analyzer", "ns" : "testDb.testColl", "collUuid" : UUID("5130b4df-5966-434f-85f0-f8956b5ca74e"), "startTime" : ISODate("2023-08-08T16:15:07.427Z"), "sampledReadsCount" : NumberLong(2), "sampledReadsBytes" : NumberLong(346), "sampledWritesCount" : NumberLong(3), "sampledWritesBytes" : NumberLong(904) }
Output Fields
Each output document may contain a subset of the following fields, as relevant for the operation:
$currentOp.type
The type of operation. Values are either:
op
idleSession
idleCursor
If the
$currentOp.type
isop
,$currentOp.op
provides details on the specific operation.
$currentOp.shard
The name of the shard where the operation is running.
Only present for sharded clusters.
$currentOp.client
The IP address (or hostname) and the ephemeral port of the client connection where the operation originates.
For multi-document transactions,
$currentOp.client
stores information about the most recent client to run an operation inside the transaction.For standalones and replica sets only
$currentOp.client_s
The IP address (or hostname) and the ephemeral port of the
mongos
where the operation originates.For sharded clusters only
$currentOp.clientMetadata
Additional information on the client.
For multi-document transactions,
$currentOp.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 theappName
field.
$currentOp.active
A boolean value specifying whether the operation has started. Value is
true
if the operation has started orfalse
if the operation is idle, such as an idle connection, an inactive session, or an internal thread that is currently idle. An operation can be active even if the operation has yielded to another operation.
$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 amongos
or a shard member) returns a shard's coordination information only for transactions the shard is currently coordinating.To filter for only the commit coordination metrics:
db.getSiblingDB("admin").aggregate( [ { $currentOp: { allUsers: true, idleSessions: true } }, { $match: { desc: "transaction coordinator" } } ] ) A specific commit coordination operation (i.e.
type
isop
anddesc
is"TransactionCoordinator"
) spawned by the transaction coordinator.
Note
If run with idleSessions: false,
$currentOp
does not return the$currentOp.twoPhaseCommitCoordinator
information ininactive
state
If access control is enabled and allUsers: false,
$currentOp
does not return$currentOp.twoPhaseCommitCoordinator
information.
$currentOp.twoPhaseCommitCoordinator.lsid
The session identifier for the multi-shard transaction.
The combination of the
lsid
andtxnNumber
identifies the transaction.Available for both the commit coordination metrics and for specific coordination operation.
$currentOp.twoPhaseCommitCoordinator.txnNumber
The transaction number for the multi-shard transaction.
The combination of the
txnNumber
andlsid
identifies the transaction.Available for both the commit coordination metrics and for specific coordination operation.
$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.
$currentOp.twoPhaseCommitCoordinator.numParticipants
Number of shards participating in this commit.
Only available for the commit coordination metrics.
$currentOp.twoPhaseCommitCoordinator.state
The current step/state of the commit coordination process.
Step/stageDescriptioninactive
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
.
$currentOp.twoPhaseCommitCoordinator.commitStartTime
The date and time when the commit started.
Only available for the commit coordination metrics.
$currentOp.twoPhaseCommitCoordinator.hasRecoveredFromFailover
A boolean that indicates whether the commit coordination was restarted due to failover on the shard that is coordinating the commit.
If
hasRecoveredFromFailover
is true, then the times specified in$currentOp.twoPhaseCommitCoordinator.stepDurations
may not be accurate for all steps.Only available for the commit coordination metrics.
$currentOp.twoPhaseCommitCoordinator.stepDurations
A document that contains the duration, in microseconds, of the completed or in-progress
steps/state
of the active process as well as the cumulative total duration; for example:"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 instepDurations
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.
$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.
$currentOp.twoPhaseCommitCoordinator.deadline
The date and time by which the commit must finish.
Only available for the commit coordination metrics.
$currentOp.effectiveUsers
An array that contains a document for each user associated with the operation. Each user document contains the
user
name and the authenticationdb
.
$currentOp.runBy
An array that contains a document for each user who is impersonating the
effectiveUser(s)
for the operation. The runBy document contains theuser
name and the authenticationdb
. In general, the impersonating user is the__system
user; e.g."runBy" : [ { "user" : "__system", "db" : "local" } ]
$currentOp.opid
The identifier for the operation. You can pass this value to
db.killOp()
inmongosh
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.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 present if the operation is running; i.e. if
active
istrue
.
$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 present if the operation is running; i.e. if
active
istrue
.
$currentOp.transaction
A document that contains multi-document transaction information.
Only present if the operation is part of a transaction:
On a replica set.
On a sharded cluster if
$currentOp
is run without localOps:true. The transaction information is per shard.On a sharded cluster if
$currentOp
is run with localOps:true. The transaction information is a composite view rather than per shard.
$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.globalReadTimestamp
The timestamp of the snapshot read by the operations in the sharded cluster transaction that uses "snapshot" read concern. For transactions on sharded clusters, the read concern
"snapshot"
of the data is synchronized across shards; i.e. other read concerns cannot guarantee that the data is from the same snapshot view across the shards.Only present when run with localOps: true for sharded cluster transactions.
$currentOp.transaction.readTimestamp
The timestamp of the snapshot being read by the operations in this transaction
Only present if the operation is part of a multi-document transaction. However, the field is not returned if:
the transaction is on a sharded cluster and uses "snapshot" read concern, and
$currentOp
is run with localOps: true.
Instead,
$currentOp.transaction.globalReadTimestamp
is returned.
$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, in microseconds, for the transaction.
The
timeActiveMicros
value added to thetimeInactiveMicros
should equal thetimeOpenMicros
.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 thetimeInactiveMicros
should equal thetimeOpenMicros
.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 thetimeActiveMicros
should equal thetimeOpenMicros
.Only present if the operation is part of a multi-document transaction.
$currentOp.transaction.numParticipants
Number of shards participating in this transaction.
Only present if the operation is part of a transaction on a sharded cluster and
$currentOp
is run with localOps: true
$currentOp.transaction.participants
An array of documents detailing the participating shards in this transaction. Each document contains the name, a flag indicating if the shard acts as the commit coordinator, and a flag indicating if the shard is only involved in read operations for the transaction.
{ "name" : "shardA", "coordinator" : false, "readOnly" : false } Only present if the operation is part of a transaction on a sharded cluster and
$currentOp
is run with localOps: true
$currentOp.transaction.numReadOnlyParticipants
Number of shards only affected by read operations in this transaction.
Only present if the operation is part of a transaction on a sharded cluster and
$currentOp
is run with localOps: true
$currentOp.transaction.numNonReadOnlyParticipants
Number of shards affected by operations other than reads in this transaction.
Only present if the operation is part of a transaction on a sharded cluster and
$currentOp
is run with localOps: true
$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
+ thetransactionLifetimeLimitSeconds
.For more information, see Runtime Limit for transactions.
Only present if the operation is part of a multi-document transaction.
$currentOp.op
A string that identifies the specific operation type. Only present if
$currentOp.type
isop
.The possible values are:
"none"
"update"
"insert"
"query"
"command"
"getmore"
"remove"
"killcursors"
"command"
operations include most commands such as thecreateIndexes
,aggregate
, andfindAndModify
."query"
operations includefind
operations and OP_QUERY operations.
$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>"
.
$currentOp.command
A document containing the full command object associated with this operation.
For example, the following output contains the command object for a
find
operation on a collection nameditems
in a database namedtest
:"command" : { "find" : "items", "filter" : { "sku" : 1403978 }, ... "$db" : "test" } The following example output contains the command object for a
getMore
operation generated by a command with cursor ID19234103609
on a collection nameditems
in a database namedtest
:"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'scomment
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. A comment may be attached to any database command.
$currentOp.cursor
A document that contains the cursor information for
idleCursor
andgetmore
operations; i.e. wheretype
isidleCursor
orop
isgetmore
.If reporting on a
getmore
operation before thegetmore
has accessed its cursor information, thecursor
field is not available.$currentOp.cursor.lastAccessDate
The date and time when the cursor was last used.
If the cursor is actively in use (i.e.
op
isgetmore
and thetype
is notidleCursor
), thenlastAccessDate
reports either the time the previousgetmore
ended or the time the cursor was created if this is the firstgetmore
.
$currentOp.cursor.noCursorTimeout
The flag that indicates that the cursor doesn't 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.
$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
oraggregate
) which originally created the cursor.
$currentOp.cursor.planSummary
A string that 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.Not available when running with
localOps: true
onmongos
or when reporting onidleCursors
.
$currentOp.cursor.queryFramework
New in version 6.2.
A string that specifies the query framework used to process an operation.
$currentOp.planSummary
A string that specifies whether the cursor uses a collection scan (
COLLSCAN
) or an index scan (IXSCAN { ... }
).Not available when running with
localOps: true
onmongos
.
$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 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.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 avalidate
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,
$currentOp.dataThroughputAverage
The average amount of data (in MiB) processed by the
validate
operation. Only available for avalidate
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,
$currentOp.waitingForLatch
The
waitingForLatch
document is only available if the operation is waiting to acquire an internal locking primitive (a.k.a. a latch) or for an internal condition to be met.For example,
"waitingForLatch" : { "timestamp" : ISODate("2020-03-19T23:25:58.412Z"), "captureName" : "FutureResolution", "backtrace" : [ ] // Only if backtrace: true }, Output FieldDescriptiontimestampThe date and time at which the operation started to wait.captureNameThe internal name of the section where the operation is currently blocked.backtraceThe callstack, if available. The field is only included if backtrace: true.
$currentOp.locks
The
locks
document reports the type and mode of locks the operation currently holds. The possible lock types are as follows:Lock TypeDescriptionParallelBatchWriterMode
Represents a lock for parallel batch writer mode.
In earlier versions, PBWM information was reported as part of the
Global
lock information.ReplicationStateTransition
Represents lock taken for replica set member state transitions.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 as follows:
Lock ModeDescriptionR
Represents Shared (S) lock.W
Represents Exclusive (X) lock.r
Represents Intent Shared (IS) lock.w
Represents Intent Exclusive (IX) lock.
$currentOp.lockStats
For each lock type and mode (see
locks
for descriptions of lock types and modes), returns the following information:$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 toacquireCount
.
$currentOp.lockStats.timeAcquiringMicros
Cumulative time in microseconds that the operation had to wait to acquire the locks.
timeAcquiringMicros
divided byacquireWaitCount
gives an approximate average wait time for the particular lock mode.
$currentOp.waitingForLock
Returns a boolean value.
waitingForLock
istrue
if the operation is waiting for a lock andfalse
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 themsg
field. Theprogress
specifies the following information:
$currentOp.killPending
Returns
true
if the operation is currently flagged for termination. When the operation encounters its next safe termination point, the operation terminates.
$currentOp.waitingForFlowControl
A boolean that indicates if the operation had to wait because of flow control.
$currentOp.flowControlStats
The flow control statistics for this operation.
$currentOp.totalOperationTimeElapsed
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.
$currentOp.remainingOperationTimeEstimated
The estimated time remaining in seconds for the current resharding operation. The time is set to -1 when a new resharding operation starts.
Only present when a resharding operation is taking place. This field may not be present if an estimate cannot not be computed.
New in version 5.0.
$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.totalCopyTimeElapsed
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.
$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.totalApplyTimeElapsed
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.
$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.totalCriticalSectionTimeElapsed
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.
$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.
StateDescriptionunused
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.
StateDescriptionunused
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.
StateDescriptionunused
The resharding operation is about to start or recovering from a primary failover.initializing
The resharding coordinator has inserted the coordinator document intoconfig.reshardingOperations
and has added thereshardingFields
to theconfig.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 theabortReshardCollection
command (or thesh.abortReshardCollection()
method) was run.committing
The resharding coordinator removes theconfig.collections
entry for the temporary resharding collection. The coordinator then adds therecipientFields
to the source collection's entry.New in version 5.0.
$currentOp.opStatus
The current state of a resharding operation.
Only present if a resharding operation is taking place. Once the operation has completed, the operation is removed from
currentOp
output.StateDescriptionactively running
The resharding operation is actively running.success
The resharding operation has succeeded.failure
The resharding operation has failed.canceled
The resharding operation was canceled.New in version 5.0.
$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.
Only reported when running
$currentOp
onmongos
.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.