Computation strategies

In this section, we list some common computation strategies for on-chain processing.

Stop-the-world computation

Stop-the-world computation represents a kind of computation where we need to iterate over the full account list. In this case, because the account list can be huge, the computation itself is expensive. However, we must ensure block processing takes minimal time to ensure network safety and to ensure proof of work cannot be exploited. There are two methods to do this:

  • State copying and churn limit: whenever we need to do stop-the-world computation, copy the current state into a new structure, and process accounts with a churn limit. In this way, we process the whole computation over the span of potentially hundreds of blocks, which can last a day or two.

  • Data migration: when an account is touched, process the computation and migrate the account into a new data structure. In this way, we always know what accounts are not processed and what accounts are processed, by checking whether it is in the old or new data structure.