this module will block nginx main cycle(block other requests)

[idning]

hi,

ngx module code ::

/* Fetch the chunk from mongo */
do {
    e = FALSE;
    cursors[i] = gridfile_get_chunks(&gfile, i, 1);
    if (!(cursors[i] && mongo_cursor_next(cursors[i]) == MONGO_OK)) {
        e = TRUE; ecounter++;
        if (ecounter > MONGO_MAX_RETRIES_PER_REQUEST 
            || ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
            || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Mongo connection dropped, could not reconnect");
            if(&mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_HTTP_SERVICE_UNAVAILABLE;
        }
    }
} while (e);

this will call mongo_cursor_get_more::

static int mongo_cursor_get_more( mongo_cursor *cursor ) {
    int res;
    ...
    mm = mongo_message_create( 16 /*header*/
                               +4 /*ZERO*/
                               +sl
                               +4 /*numToReturn*/
                               +8 /*cursorID*/
                               , 0, 0, MONGO_OP_GET_MORE );



    res = mongo_message_send( cursor->conn, mm );
    res = mongo_read_response( cursor->conn, &( cursor->reply ) );
}

static int mongo_read_response( mongo *conn, mongo_reply **reply ) {

    mongo_env_read_socket( conn, &head, sizeof( head ) );
    //which will do a blocking read.
    ...
}    

the blocking read will block nginx worker, other request will be blocked.

have you make any benchmark on this module?