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Sync Types

This chapter describes basic concepts of different sync types. For more detail, please refer to documents in Funambol.

Two-way sync

The two-way sync is a normal synchronization type in which the client and the server exchange information about the modified data in these devices. The client is always the device which first sends the modifications. According to the information from the client, the server processes the synchronization request and the data from the client is compared and unified with the data in the server. After that, the server sends its modified data to the client device, which is then able to update its database with the data from the server.

Slow sync

The slow sync is a form of the two-way synchronization in which all items in one or more databases are compared with each other on a field-by-field basis. In practice, the slow sync means that the client sends all its data in a database to the server and the server does the sync analysis (field-by-field) for this data and the data in the server. After the sync analysis, the server returns all needed modifications back to the client. Also, the client returns the Map items for all data items, which were added by the server.

One-way sync

After any of the one-way sync operations following, the client and the server might lost sync to each other since they may then have different contents.

One-way sync from the client

The one-way sync from the client is the sync type in which the client sends all modifications to the server but the server does not send its modifications back to the client. Thus, after this type of sync, the server includes all modified data from the client but the client does not know about modifications in the server. This operation just exports data from the client to the server.

Please note, even if the client asks for one-way sync from the client, sometimes the server may still require two-way sync, particularly when the client has updates. The client will then do slow sync as requested by the server.

Replace All of the Server Data with Local Data (Refresh sync from client)

The "refresh sync from client" is a synchronization type in which the client sends all its data from a database to the server. The server is expected to replace all data in the target database with the data sent by the client. This means that the client overwrites all data in the server database. This operation is more like exporting data to the server, in addition, all data in the server will be replaced.

One-way sync from the server

This one-way sync from the server is the case in which the client gets all modifications from the server but the client does not send its modifications to the server. Thus, after this type of sync, the client includes all modified data from the server but the server does not know about modifications in the client. This operation imports data from the server.

Please note, even if the client asks for one-way sync from the server, sometimes the server may still require two-way sync, particularly when the client has updates.

Replace All of Local Data with Server Data (Refresh sync from server)

The "refresh sync from client" is a synchronization type in which the server sends all its data to the client. The client is expected to replace all data in the database with the data from server. Open Contacts would prompt for conformation before deleting all contact info in the local database.