Cosmos Garbage Collector

CLI tool to really prune a Cosmos SDK full node.

Assumptions

• Target chain is running Cosmos SDK version v0.46 or v0.47 (does NOT work on v0.45)
• Full node uses LevelDB (support for other DBs can be added if need be)

Installing

Using Go:

go install github.com/coinhall/cosmos-gc/cmd/cosmos-gc

OR, from source:

git clone https://github.com/coinhall/cosmos-gc
cd cosmos-gc
make install

Running

Make sure to stop the full node first (if it is running). Then, run the following command:

cosmos-gc PATH_TO_APP_HOME # eg. ~/.terra

You may proceed to start the full node after the above command has finished.

Implementation Notes

• A new db is created to replace the old db as opposed to pruning the old db as deletions are extremely slow
• Latest block height must be read from each database (ie. cannot read from one db and assume it's the same for all)
• state.db must contain validatorsKey for last valset changed height, latest height, latest height + 1, and latest height + 2; else, starting the daemon will result in consensus failure
• application.db holds the IAVL tree for Cosmos SDK, iteration itself is already very expensive (worse still for reads and writes)