Plutus Scripts Evaluation

Tools used to:

1. Accumulate Plutus script evaluation events by replaying blockchain folding over the Ledger state and extracting PlutusScriptEvaluationEvents.
2. Record accumulated events:
   1. On the file system as "dump" files.
   2. In the PostgreSQL database.

How to use

0. Initialise the PostgreSQL database and connection using files in the database folder:
   • There is a pgModeler (Open-source tool) project for it,
   • As well as the DDL statements.
1. Create .envrc.local with the following content (adjust the paths as needed):

    export CARDANO_NODE_SOCKET_PATH="/home/projects/cardano/node/node-state/mainnet/node.sock"
    export CARDANO_NODE_CONFIG_PATH="/home/projects/cardano/playground/docs/environments/mainnet/config.json"
    export DB_CONN_STRING="dbname=mainnet_plutus_events"

2. Enter the nix shell using either nix develop command or direnv hooked to your shell.
3. See available commands by entering info in the shell.
4. Run the script dump job using the dump command or script upload job with the load command.

How to re-evaluate recorded Plutus Script evaluations locally

The database contains plutus script evaluation events from Mainnet which can be replayed locally to re-evaluate the scripts.

There is less value in re-evaluating scripts without any changes, as one would simply re-obtain results that are already known. However, this can be useful when the script evaluation logic has changed, and one wants to compare results produced by the new logic with the old results.

The repository contains a program that can be used to re-evaluate the scripts locally. You can use this program as a basis for your own re-evaluation, where you can modify various parameters to suit your needs:

• The Main module of the evaluate-scripts executable.
• The main workhorse, function evaluateScripts in the Evaluation module does the boring parts (aggregating relevant script evaluation inputs, streaming the data from DB to a local computer, decoding CBOR, forking worker threads) so that you can do the interesting part: traverse script evaluations from the Mainnet accessing all of the original evaluation inputs to re-interpret them accordingly to your task;

If a task requires maintaining local state (accumulator) during the evaluation, you can use the accumulateScripts function in the Evaluation module. This function is a more general version of evaluateScripts that allows you to maintain local state during the evaluation.