Class to encapsulate client side "Write Concern" concept. More...

#include <write_concern.h>

Public Member Functions
	WriteConcern ()
	Default write concern: equivalent to acknowledged.

int32_t	nodes () const
	Returns an integer representing the number of nodes required for write to be considered successful.

const std::string &	mode () const
	Returns a string representing the write concern mode.

bool	journal () const
	If write will only be considered successful when committed to journal.

bool	fsync () const
	If write will only be considered successful when committed to data files.

int32_t	timeout () const
	Length of time to block waiting for nodes, journal, or fsync.

WriteConcern &	nodes (int w)
	Sets the number of nodes required for write to be successful.

WriteConcern &	mode (const StringData &w)
	Sets the type of nodes required for write to be successful.

WriteConcern &	journal (bool j)
	Sets whether journal is required for write to be successful.

WriteConcern &	fsync (bool fsync)
	Sets whether fsync is required for write to be successful.

WriteConcern &	timeout (int timeout)
	Sets timeout to wait for write to be successful.

bool	requiresConfirmation () const
	Whether we need to send getLastError for this WriteConcern.

bool	hasMode () const
	Whether the write concern currently reflects a mode.

BSONObj	obj () const
	Turn write concern into an object for inclusion in GetLastError or write command.

Static Public Attributes
static const char	kMajority []
	Using nodes(kMajority) confirms that write operations have propagated to the majority of a replica set.

static const WriteConcern	unacknowledged
	Fire and forget.

static const WriteConcern	acknowledged
	A single node acknowledges the write, equivalent to default constructor.

static const WriteConcern	journaled
	A single node acknowledges the write operation was committed to journal.

static const WriteConcern	replicated
	Two nodes have acknowledged receipt of the write operation.

static const WriteConcern	majority
	A majority of nodes acknowledges (replica set)

Detailed Description

Class to encapsulate client side "Write Concern" concept.

Write concern describes the guarantee that MongoDB provides when reporting on the success of a write operation.

Example usage: WriteConcern wc = WriteConcern().nodes(3).journal(false);

Member Function Documentation

◆ fsync()

bool mongo::WriteConcern::fsync ( ) const

If write will only be considered successful when committed to data files.

Returns: true if write will block on MongoDB fsync

◆ journal()

bool mongo::WriteConcern::journal ( ) const

If write will only be considered successful when committed to journal.

Returns: true if write will block on MongoDB journal

◆ mode()

const std::string & mongo::WriteConcern::mode ( ) const

Returns a string representing the write concern mode.

If set this becomes the "w" parameter when sent to the server.

Returns: nodes required as std::string

◆ nodes()

int32_t mongo::WriteConcern::nodes ( ) const

Returns an integer representing the number of nodes required for write to be considered successful.

If set this becomes the "w" parameter when sent to the server.

Returns: number of nodes required

◆ timeout()

int32_t mongo::WriteConcern::timeout ( ) const

Length of time to block waiting for nodes, journal, or fsync.

Returns: int representing milliseconds to wait for write

Member Data Documentation

◆ kMajority

const char mongo::WriteConcern::kMajority[]

static

Using nodes(kMajority) confirms that write operations have propagated to the majority of a replica set.

This allows you to avoid hard coding assumptions about the size of your replica set into your application.

The documentation for this class was generated from the following file:

src/mongo/client/write_concern.h

Public Member Functions

Static Public Attributes