ClientSession
public final class ClientSession
A MongoDB client session. This class represents a logical session used for ordering sequential operations.
To create a client session, use startSession
or withSession
on a MongoClient
.
If causalConsistency
is not set to false
when starting a session, read and write operations that use the session
will be provided causal consistency guarantees depending on the read and write concerns used. Using “majority”
read and write preferences will provide the full set of guarantees. See
https://docs.mongodb.com/manual/core/read-isolation-consistency-recency/#sessions for more details.
e.g.
let opts = MongoCollectionOptions(readConcern: .majority, writeConcern: .majority)
let collection = database.collection("mycoll", options: opts)
try client.withSession { session in
try collection.insertOne(["x": 1], session: session)
try collection.find(["x": 1], session: session)
}
To disable causal consistency, set causalConsistency
to false
in the ClientSessionOptions
passed in to either
withSession
or startSession
.
See also
-
The client used to start this session.
Declaration
Swift
public let client: MongoClient
-
The most recent cluster time seen by this session. This value will be nil if either of the following are true:
- No operations have been executed using this session and
advanceClusterTime
has not been called. - This session has been ended.
Declaration
Swift
public var clusterTime: BSONDocument? { get }
- No operations have been executed using this session and
-
The operation time of the most recent operation performed using this session. This value will be nil if either of the following are true:
- No operations have been performed using this session and
advanceOperationTime
has not been called. - This session has been ended.
Declaration
Swift
public var operationTime: BSONTimestamp? { get }
- No operations have been performed using this session and
-
The options used to start this session.
Declaration
Swift
public var options: ClientSessionOptions? { get }
-
Advances the clusterTime for this session to the given time, if it is greater than the current clusterTime. If the session has been ended, or if the provided clusterTime is less than the current clusterTime, this method has no effect.
Declaration
Swift
public func advanceClusterTime(to clusterTime: BSONDocument)
Parameters
clusterTime
The session’s new cluster time, as a
Document
like["cluster time": Timestamp(...)]
-
Advances the operationTime for this session to the given time if it is greater than the current operationTime. If the session has been ended, or if the provided operationTime is less than the current operationTime, this method has no effect.
Declaration
Swift
public func advanceOperationTime(to operationTime: BSONTimestamp)
Parameters
operationTime
The session’s new operationTime
-
Starts a multi-document transaction for all subsequent operations in this session.
Any options provided in
options
will override the default transaction options for this session and any options inherited fromMongoClient
.Operations executed as part of the transaction will use the options specified on the transaction, and those options cannot be overridden at a per-operation level. Any options that overlap with the transaction options which can be specified at a per operation level (e.g. write concern) will be ignored if specified. This includes options specified at the database or collection level on the object used to execute an operation.
The transaction must be completed with
commitTransaction
orabortTransaction
. An in-progress transaction is automatically aborted whenClientSession.end()
is called.Throws
Throws:
MongoError.CommandError
if an error occurs that prevents the command from executing.MongoError.LogicError
if the session already has an in-progress transaction.MongoError.LogicError
ifstartTransaction
is called on an ended session.
Declaration
Swift
public func startTransaction(options: TransactionOptions? = nil) throws
Parameters
options
The options to use when starting this transaction
-
Commits a multi-document transaction for this session. Server and network errors are not ignored.
Throws
Throws:
MongoError.CommandError
if an error occurs that prevents the command from executing.MongoError.LogicError
if the session has no in-progress transaction.MongoError.LogicError
ifcommitTransaction
is called on an ended session.
Declaration
Swift
public func commitTransaction() throws
-
Aborts a multi-document transaction for this session. Server and network errors are ignored.
Throws
Throws:
MongoError.LogicError
if the session has no in-progress transaction.MongoError.LogicError
ifabortTransaction
is called on an ended session.
Declaration
Swift
public func abortTransaction() throws