SYNOPSIS

          bool
          mongoc_database_read_command_with_opts (mongoc_database_t *database,
                                                  const bson_t *command,
                                                  const mongoc_read_prefs_t *read_prefs,
                                                  const bson_t *opts,
                                                  bson_t *reply,
                                                  bson_error_t *error);

       Execute  a  command  on the server, applying logic that is specific to commands that read,
       and taking the MongoDB server version into account. To send a raw command  to  the  server
       without any of this logic, use mongoc_database_command_simple().

       Use this function for commands that read such as "count" or "distinct".

       Read  preferences,  read concern, and collation can be overridden by various sources. In a
       transaction, read concern and write concern are prohibited in opts and the read preference
       must  be  primary or NULL. The highest-priority sources for these options are listed first
       in the following table. No write concern is applied.

                             ┌─────────────────┬──────────────┬───────────┐
                             │Read Preferences │ Read Concern │ Collation │
                             ├─────────────────┼──────────────┼───────────┤
                             │read_prefs       │ opts         │ opts      │
                             ├─────────────────┼──────────────┼───────────┤
                             │Transaction      │ Transaction  │           │
                             ├─────────────────┼──────────────┼───────────┤
                             │database         │              │           │
                             └─────────────────┴──────────────┴───────────┘

       See the example for transactions and for the "distinct" command with opts.

       reply is always initialized, and must be freed with bson_destroy().

       This function is considered a retryable read operation.  Upon a transient error (a network
       error, errors due to replica set failover, etc.) the operation is safely retried once.  If
       retryreads is false in the URI (see mongoc_uri_t) the retry behavior does not apply.

       Retry logic occurs regardless of  the  underlying  command.  Retrying  mapReduce  has  the
       potential  for degraded performance.  Retrying a getMore command has the potential to miss
       results.    For    those    commands,    use     generic     command     helpers     (like
       mongoc_database_command_with_opts()) instead.

PARAMETERS

       • database: A mongoc_database_t.

       • command: A bson_t containing the command specification.

       • read_prefs: An optional mongoc_read_prefs_t.

       • opts: A bson_t containing additional options.

       • reply: A maybe-NULL pointer to overwritable storage for a bson_t to contain the results.

       • error: An optional location for a bson_error_t or NULL.

       opts may be NULL or a BSON document with additional command options:

       • readConcern:  Construct  a mongoc_read_concern_t and use mongoc_read_concern_append() to
         add    the    read    concern    to    opts.    See     the     example     code     for
         mongoc_client_read_command_with_opts().  Read  concern  requires  MongoDB  3.2 or later,
         otherwise an error is returned.

       • sessionId:       First,       construct       a       mongoc_client_session_t       with
         mongoc_client_start_session().      You     can     begin     a     transaction     with
         mongoc_client_session_start_transaction(), optionally  with  a  mongoc_transaction_opt_t
         that     overrides     the     options     inherited     from    database,    and    use
         mongoc_client_session_append() to add the session to opts.  See  the  example  code  for
         mongoc_client_session_t.

       • collation:  Configure  textual comparisons. See Setting Collation Order, and the MongoDB
         Manual entry on Collation. Collation requires MongoDB 3.2 or later, otherwise  an  error
         is returned.

       • serverId:  To target a specific server, include an int32 "serverId" field. Obtain the id
         by calling mongoc_client_select_server(),  then  mongoc_server_description_id()  on  its
         return value.

       Consult the MongoDB Manual entry on Database Commands for each command's arguments.

ERRORS

       Errors are propagated via the error parameter.

RETURNS

       Returns true if successful. Returns false and sets error if there are invalid arguments or
       a server or network error.

EXAMPLE

       See the example code for mongoc_client_read_command_with_opts().

AUTHOR

       MongoDB, Inc

COPYRIGHT

       2017-present, MongoDB, Inc