mongoc_write_concern_t tells the driver what level of acknowledgment to await from the server. The default, MONGOC_WRITE_CONCERN_W_DEFAULT, is right for the great majority of applications.
You can specify a write concern on connection objects, database objects, collection objects, or per-operation.
See Write Concern on the MongoDB website for more information.
WRITE CONCERN LEVELS
- MONGOC_WRITE_CONCERN_W_DEFAULT (1)
- By default, writes block awaiting acknowledgment from MongoDB. Acknowledged write concern allows clients to catch network, duplicate key, and other errors.
- MONGOC_WRITE_CONCERN_W_UNACKNOWLEDGED (0)
- With this write concern, MongoDB does not acknowledge the receipt of write operation. Unacknowledged is similar to errors ignored; however, mongoc attempts to receive and handle network errors when possible.
- MONGOC_WRITE_CONCERN_W_MAJORITY (majority)
- Block until a write has been propagated to a majority of the nodes in the replica set.
- Block until a write has been propagated to at least n nodes in the replica set.
- Block until the node receiving the write has committed the journal.
The write concern MONGOC_WRITE_CONCERN_W_ERRORS_IGNORED (value -1) is a deprecated synonym for MONGOC_WRITE_CONCERN_W_UNACKNOWLEDGED (value 0), and will be removed in the next major release.