Execution Witness Service

[frisitano]

Describe the feature

To generate proofs, we require an execution witness. Due to the architecture of reth, producing execution traces for historical blocks is inefficient and impractical for very old blocks. We should implement a service that can be used to persist execution traces and then serve them when required. Old execution traces can be periodically purged.

Proposed Architecture:

• ExEx: Used to generate execution traces for new blocks and persist them to the database
• Rpc extension: Used to serve persisted execution witnesses and purge historical execution witnesses which are no longer required

Additional context

No response

[Thegaram]

What's the benefit of using an ExEx, as opposed to using an independent service that queries via RPC? ExEx backfill and pruning might be problematic.