Data provisioning (where do the mappings come from?)
The swift model data are stored in the datastore database. This database contains all mappings, ICAO codes etc. used with swift.
There are two ways to obtain these data. swift will always download the data and store them locally in cache files.
- the mapping tool will download the data via web services directly from the database
- the client (pilot client) will download the data as files, we call them shared data file . The files are generated from the database and distributed to different servers. The content of the //shared files// is basically the same as in the web services, but it is a snapshot of the time when they are generated.
for mapping (direct access to swift database)
- the mapping tool writes directly to the database as all users editing the data always need the latest data. Also they have to work on the same data.
- if the database is down, users can still use the cached data, but not write data. This is not really a problem as the users can save the stash and continue at a later time
- there are only a few users concurrently creating mappings. Creating mappings is a specialized task only for power users.
- Since only few members work directly with the database it is not a performance problem.
for the pilot client (shared files)
there are much more users using the pilot client
during a flight the model data must not be updated, as this would consume too much time and affect interpolation
there are too many users so that not everybody can download directly from the database.
the pilot client downloads the shared files. as these files are available on multiple servers:
- the download is redundant, if one server is down the shared files can be downloaded from another server
- the traffic is distributed, the swift team can open new download servers and hence share the network traffic