Transaction Pre-Processing for Miners

[gregorycoppola]

Abstract

We identify the critical period as the period of time when a new Bitcoin block has been produced and it is time for each Stacks miner to make a new Stacks block. We propose that miner resources are not the bottleneck.

We propose that all (or as many as possible) transactions should be processed by miners outside of the critical period.

Some examples would be:

• pre-caching of MARF reads into RAM
• pre-identify TransactionTooBig violations
• allow miner to use exact costs for transactions, instead of estimates, to optimize blocks

Current Bottleneck

We want to maximize throughput on the Stacks chain. This means filling each block (or block along with micro-blocks). We are limited by:

Limiting factors:

• block limits
  • needed to prevent
    • verifiers from being overwhelmed
    • next miner from being overwhelmed
• time between Bitcoin blocks
  • this is inherently unpredictable
    • a miner doesn't know how long they have to make their block
    • so need to move as fast as possible

Note that, what we have not included among the limiting factors it the limiting factors it the computational resources of the miner.

Not the limiting factor:

• computational resources of the miner

Critical Period

Once a new Bitcoin block has been announced the race is on to create a new Stacks block, and submit the corresponding bit to the Bitcoin chain. We will call this the critical period:

• critical period
  • time after a new Bitcoin block has been announced
  • race is on for miners to create a new Stacks block and get their corresponding bid in to the Bitcoin chain
  • we don't know how long the critical period will last
  • miner's block must be done, and bid in, before end of critical period

Pre-Processing Opportunities

Our proposal is:

• move as much computation as possible out of the critical period
• pre-process in other threads, or at other times, so that critical period computation can be faster

Examples of things that can be pre-processed:

• pre-cache MARF reads in RAM, so we don't have to read from disk in the critical period
• identify transactions that will hit TransactionTooBig, so we don't have to run through these during the critical period
• identify the actual cost of a transaction, so that miner's can create the most profitable block possible