Class representing the server-side requirement for reporting the success of a write operation. More...

#include <write_concern.hpp>

Public Types
enum class	level
	A class to represent the special case values for write_concern::nodes. More...

Public Member Functions
	write_concern ()
	Constructs a new write_concern.

	write_concern (const write_concern &)
	Copy constructs a write_concern.

write_concern &	operator= (const write_concern &)
	Copy assigns a write_concern.

	write_concern (write_concern &&) noexcept
	Move constructs a write_concern.

write_concern &	operator= (write_concern &&) noexcept
	Move assigns a write_concern.

	~write_concern ()
	Destroys a write_concern.

void	journal (bool journal)
	Sets the journal parameter for this write concern.

void	nodes (std::int32_t confirm_from)
	Sets the number of nodes that are required to acknowledge the write before the operation is considered successful.

void	acknowledge_level (level confirm_level)
	Sets the acknowledge level.

void	majority (std::chrono::milliseconds timeout)
	Requires that a majority of the nodes in a replica set acknowledge a write operation before it is considered a success.

void	tag (stdx::string_view tag)
	Sets the name representing the server-side getLastErrorMode entry containing the list of nodes that must acknowledge a write operation before it is considered a success.

void	timeout (std::chrono::milliseconds timeout)
	Sets an upper bound on the time a write concern can take to be satisfied.

bool	journal () const
	Gets the current status of the journal parameter.

stdx::optional< std::int32_t >	nodes () const
	Gets the current number of nodes that this write_concern requires operations to reach.

level	acknowledge_level () const
	Gets the current acknowledgment level.

stdx::optional< std::string >	tag () const
	Gets the current getLastErrorMode that is required by this write_concern.

bool	majority () const
	Gets whether the majority of nodes is currently required by this write_concern.

std::chrono::milliseconds	timeout () const
	Gets the current timeout for this write_concern.

bool	is_acknowledged () const
	Gets whether this write_concern requires an acknowledged write.

bsoncxx::document::value	to_document () const
	Gets the document form of this write_concern.

Detailed Description

Class representing the server-side requirement for reporting the success of a write operation.

The strength of the write concern setting determines the level of guarantees that you will receive from MongoDB regarding write durability.

Weaker requirements that provide fewer guarantees report on success quickly while stronger requirements that provide greater guarantees will take longer (or potentially forever, if the write_concern's requirements are not satisfied and no timeout is set).

MongoDB drivers allow for different levels of write concern to better address the specific needs of applications. Clients may adjust write concern to ensure that the most important operations persist successfully to an entire MongoDB deployment. However, for other less critical operations, clients can adjust the write concern to ensure better performance rather than persistence to the entire deployment.

See also: https://docs.mongodb.com/manual/core/write-concern/

Member Enumeration Documentation

◆ level

enum class mongocxx::write_concern::level

strong

A class to represent the special case values for write_concern::nodes.

See also: https://docs.mongodb.com/manual/reference/write-concern/#w-option

Member Function Documentation

◆ acknowledge_level() [1/2]

level mongocxx::write_concern::acknowledge_level ( ) const

Gets the current acknowledgment level.

See also: https://docs.mongodb.com/manual/reference/write-concern/#w-option

Returns: The acknowledgment level.

◆ acknowledge_level() [2/2]

void mongocxx::write_concern::acknowledge_level ( level confirm_level )

Sets the acknowledge level.

See also: https://docs.mongodb.com/manual/reference/write-concern/#w-option

Parameters

confirm_level Either level::k_unacknowledged, level::k_acknowledged, level::k_default, or level::k_majority.

Note: the acknowledge level of level::k_tag is set automatically when a tag is set.

Warning: Setting this to level::k_unacknowledged disables write acknowledgment and all other write concern options.; Unacknowledged writes using dollar-prefixed or dotted keys may be silently rejected by pre-5.0 servers.

Exceptions

Throws mongocxx::exception for setting a tag acknowledge level. Use tag() instead.

◆ is_acknowledged()

bool mongocxx::write_concern::is_acknowledged ( ) const

Gets whether this write_concern requires an acknowledged write.

Returns: Whether this write concern requires an acknowledged write.

◆ journal() [1/2]

bool mongocxx::write_concern::journal ( ) const

Gets the current status of the journal parameter.

Returns: true if journal is required, false if not.

◆ journal() [2/2]

void mongocxx::write_concern::journal ( bool journal )

Sets the journal parameter for this write concern.

Parameters

journal If true confirms that the mongod instance has written the data to the on-disk journal before reporting a write operations was successful. This ensures that data is not lost if the mongod instance shuts down unexpectedly.

◆ majority() [1/2]

bool mongocxx::write_concern::majority ( ) const

Gets whether the majority of nodes is currently required by this write_concern.

Returns: The current majority setting.

◆ majority() [2/2]

void mongocxx::write_concern::majority ( std::chrono::milliseconds timeout )

Requires that a majority of the nodes in a replica set acknowledge a write operation before it is considered a success.

Parameters

timeout The amount of time to wait before the write operation times out if it cannot reach the majority of nodes in the replica set. If the value is zero, then no timeout is set.

Exceptions

mongocxx::logic_error for an invalid timeout value.

◆ nodes() [1/2]

stdx::optional< std::int32_t > mongocxx::write_concern::nodes ( ) const

Gets the current number of nodes that this write_concern requires operations to reach.

This value will be unset if the acknowledge_level is set to majority, default, or tag.

This is unset by default.

See also: https://docs.mongodb.com/manual/reference/write-concern/#w-option

Returns: The number of required nodes.

◆ nodes() [2/2]

void mongocxx::write_concern::nodes ( std::int32_t confirm_from )

Sets the number of nodes that are required to acknowledge the write before the operation is considered successful.

Write operations will block until they have been replicated to the specified number of servers in a replica set.

Parameters

confirm_from The number of replica set nodes that must acknowledge the write.

Warning: Setting the number of nodes to 0 disables write acknowledgment and all other write concern options.; Setting the number of nodes required to an amount greater than the number of available nodes will cause writes using this write concern to block forever if no timeout is set.

◆ tag() [1/2]

stdx::optional< std::string > mongocxx::write_concern::tag ( ) const

Gets the current getLastErrorMode that is required by this write_concern.

Returns: The current getLastErrorMode.

◆ tag() [2/2]

void mongocxx::write_concern::tag ( stdx::string_view tag )

Sets the name representing the server-side getLastErrorMode entry containing the list of nodes that must acknowledge a write operation before it is considered a success.

Note: the acknowledge level of level::k_tag is set automatically when a tag is set.

Parameters

tag	The string representing on of the "getLastErrorModes" in the replica set configuration.

◆ timeout() [1/2]

std::chrono::milliseconds mongocxx::write_concern::timeout ( ) const

Gets the current timeout for this write_concern.

Returns: Current timeout in milliseconds.

◆ timeout() [2/2]

void mongocxx::write_concern::timeout ( std::chrono::milliseconds timeout )

Sets an upper bound on the time a write concern can take to be satisfied.

If the write concern cannot be satisfied within the timeout, the operation is considered a failure.

Parameters

timeout The timeout (in milliseconds) for this write concern. If the value is zero, then no timeout is set.

Exceptions

mongocxx::logic_error for an invalid timeout value.

◆ to_document()

bsoncxx::document::value mongocxx::write_concern::to_document ( ) const

Gets the document form of this write_concern.

Returns: Document representation of this write_concern.

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

src/mongocxx/write_concern.hpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ level

Member Function Documentation

◆ acknowledge_level() [1/2]

◆ acknowledge_level() [2/2]

◆ is_acknowledged()

◆ journal() [1/2]

◆ journal() [2/2]

◆ majority() [1/2]

◆ majority() [2/2]

◆ nodes() [1/2]

◆ nodes() [2/2]

◆ tag() [1/2]

◆ tag() [2/2]

◆ timeout() [1/2]

◆ timeout() [2/2]

◆ to_document()