Understand correlation between client tracking and client side caching

[ayush-sarda]

This thread is aimed at understanding client tracking feature and how it's related to client side caching in the codebase.

• From what I understand CLIENT TRACKING allows us to track the keys read by the clients and based on other parameters such as BCAST and PREFIX, we are configuring our server to control which and when clients should be notified, if there is an update in some key. Client side caching on the other hand allows us to cache data locally on the client's end.
• The point I want to understand is why these two have to go together and why can't we only enable client side caching while keeping client tracking off. This is actually my current usecase where I don't want an update, if a key has been modified on the server. Instead I would keep cached keys with short lived TTL and my usecase can handle the inconsistency between server and local cache.
• If this is already supported, I want to know how to achieve the same.
• Using option ClientOption.DisableCache, disables client side caching as well and hence does not suit my usecase.
• Also, certain providers don't support CLIENT TRACKING and we are left with no choice but to disable entire client side caching.
• If there are any downsides to it, please mention those as well.

[rueian]

Hi @ayush-sarda,

The client-side caching in this library refers to server-assisted client-side caching, described here. The main advantage of server-assisted client-side caching is that it invalidates the local cache promptly whenever the key is updated on the server, and it avoids race conditions by notifying the client through the same TCP connection. This is achieved by the per-connection CLIENT TRACKING configuration, so we can't disable CLIENT TRACKING but keep server-assisted client-side caching functioning.

If you don't need the server-assisted part, then you can simply wrap around the client.Do with another caching library, such as otter.

[rueian]

Or you could try to configure CLIENT TRACKING with a non-used BCAST PREFIX .