A Closer Look Into Snapshots on Tezos — What Happens When I Change the Baker of a Delegation?

Continuing the Snapshots series on Tezos, where the previous articles answered the questions of why does it take 7 cycles for a delegation to start baking and what happens the amount of a delegation is changed, this time we will be find the answer to the question: What happens when I change the baker of a delegation?

Alte Ansichtskarten 1905 bis 1940 — Catawiki

If you haven’t yet, I recommend skimming through the past related articles to review the basic concepts:

What Happens When You Change the Baker of a Delegation?

As usual, let’s explore this scenario with a very simple example. Thurar has 10,000 XTZ (1 roll). During Cycle 18, he delegates to a baker called Liptium Crabs, who has an initial staking balance of 100,000 XTZ (10 rolls). From the baker’s perspective, the snapshots would look like:

Liptium Crabs’ Perspective: Thurar delegates 1 Roll

If Thurar does not make any changes to this delegation, his contribution to Liptium Crab’s Staking Balance will start baking in 7 cycles. Following the protocol, once the rewards are produced and unlocked after 5 more cycles, the baker should naturally pay Thurar the corresponding rewards minus fees.

But let’s say, Thurar does more research and he finds another baker that he likes more named Liptium Lobsters. To keep it simple, Liptium Lobsters also has an initial staking balance of 100,000 XTZ (10 Rolls). During Cycle 19 he decides to switch the baker of the initial delegation from Liptium Crabs to Liptium Lobsters. From Liptium Crabs’ perspective, it will look like this:

From Liptium Crabs’ Perspective: Thurar changes the baker of his delegation

As the blue area indicates, half of the snapshots taken from Cycle 18 and 19 show that Liptium Crabs’ rolls were 11. After Thurar changed the baker, the snapshots recorded that from that moment on, Liptium Crabs’ rolls were 10. On the other hand, for the new baker Liptium Lobsters, it will look like this:

From Liptium Lobsters’ Perspective: When Thurar changes the baker of his delegation

So, what happens now? Did Thurar’s delegation miss out on baking because he changed bakers after roughly one cycle? Who will pay Thurar the rewards for Cycle 25 (18 + 7)?

The answer to that is: it depends on what snapshots were taken when assigning the baking and endorsing slots for Cycle 25. As mentioned in previous articles, snapshots are taken every 256 blocks, which translates to 16 snapshots per cycle.

As bakers can track exactly which snapshot was selected from the pool of snapshots taken every cycle, Liptium Crabs’ will know if Thurar’s delegation contributed to baking for Cycle 25 or not. If yes, Liptium Crabs should transfer Thurar his corresponding rewards, although Thurar changed the baker to Liptium Lobsters.

Conclusion

In this article we have explored the scenario where a delegator, called Thurar, makes a new delegation to a first baker, called Liptium Crabs, and then changes the delegation to a different baker called Liptium Lobsters.

Bakers can track exactly which snapshots were chosen for the assignment of baking and endorsing slots of every cycle using the RPC. In this scenario, Liptium Crabs should pay the Thurar the corresponding rewards, if the chosen snapshots included Thurar’s delegation.

Broadly speaking, bakers normally track delegations automatically, calculate and pay rewards accordingly. In this case, whenever delegators make changes be it in amount or baker, it should not impact the delegator. Nonetheless, the baker community is very diverse. I recommend asking your baker what the policy should you change your delegation.