SData Linking & Synchronisation

This section describes the SData Link & Sync protocol.

The first subsections describe the linking protocol:

• Correlating with UUIDs

• Linking process

• Linking protocol

• Linking scenarios

The following subsections describe the synchronization algorithm, which is a variant of the well-known vector clock synchronization algorithm:

• Basic vector clock synchronization algorithm.

• Tick management

• Basic conflict handling

• “Digest” variant of the algorithm, which allows SData to efficiently synchronize collections of resources.

• Selecting changes with digest

• Conflict handing with digest

The following subsections describe the architecture of SData synchronization. They cover:

• Terminology

• Reference architecture

• Architecture variants

• Immediate and catch up synchronization modes.

Once the architecture has been laid out, we describe the protocol elements:

• Synchronization URLs

• Synchronization digest

• Per-resource synchronization state 

• Synchronzation feed

• Synchronization metadata.

Then, we dissect a typical synchronization pass. We show how the engine interacts with the URLs to:

• Read the target digest

• Query the source synchronization feed

• Update the target

• Handle conflicts on the target side

• Iterate through source pages 

• Log the results

We also give an example of immediate synchronization.

After this walkthrough, we describe advanced topics (not published yet): 

• Relationship handling

• Partial storage at endpoints 

• Field-level synchronization

Finally, we give some implementation hints (not published yet):

• Engine implementation notes

• Endpoint implementation notes

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