NAME

       mongoc_write_concern_t - mongoc_write_concern_t

       Write Concern abstraction

SYNOPSIS

       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.  Data-modifying  operations typically use the write concern of the object they operate on,
       and check the server response  for  a  write  concern  error  or  write  concern  timeout.  For  example,
       mongoc_collection_drop_index uses the collection's write concern, and a write concern error or timeout in
       the response is considered a failure.

       Exceptions to this principle are the generic command functions:

       • mongoc_client_command

       • mongoc_client_command_simple

       • mongoc_database_command

       • mongoc_database_command_simple

       • mongoc_collection_command

       • mongoc_collection_command_simple

       These generic command functions do not automatically apply a write concern, and they  do  not  check  the
       server response for a write concern error or write concern timeout.

       See Write Concern on the MongoDB website for more information.

WRITE CONCERN LEVELS

       Set the write concern level with mongoc_write_concern_set_w.

                    ┌──────────────────────────────────────┬───────────────────────────────────────┐
                    │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 │ With this write concern, MongoDB does │
                    │(0)                                   │ 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       │ Block  until   a   write   has   been │
                    │(majority)                            │ propagated to a majority of the nodes │
                    │                                      │ in the replica set.                   │
                    ├──────────────────────────────────────┼───────────────────────────────────────┤
                    │n                                     │ Block  until   a   write   has   been │
                    │                                      │ propagated to at least n nodes in the │
                    │                                      │ replica set.                          │
                    └──────────────────────────────────────┴───────────────────────────────────────┘

DEPRECATIONS

       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.

       mongoc_write_concern_set_fsync is deprecated.

AUTHOR

       MongoDB, Inc

COPYRIGHT

       2018, MongoDB, Inc