Remove Unsafe Pruning Flag

[wpank]

As of now, to run pruned nodes, you must use the flag --unsafe-pruning. Many people are running validators fine with pruning now. This should be removed.

[wi1dcard]

Hi @wpank , do you have any update on this issue? Is there an estimated time of removing the flag?

[bLd75]

Hi little bot, the issue is still to be addressed :)

[paradox-tt]

Seconded.

[bkchr]

We will working on this in the near future.

This issue should be tackled in the following way:

1. Remove the automatic enabling of "archive mode" when --validator is given.

   substrate/client/cli/src/params/pruning_params.rs

   Lines 42 to 65 in 293fbeb

   	pub fn state_pruning(&self, unsafe_pruning: bool, role: &Role) -> error::Result<PruningMode> {
   	// by default we disable pruning if the node is an authority (i.e.
   	// `ArchiveAll`), otherwise we keep state for the last 256 blocks. if the
   	// node is an authority and pruning is enabled explicitly, then we error
   	// unless `unsafe_pruning` is set.
   	Ok(match &self.pruning {
   	Some(ref s) if s == "archive" => PruningMode::ArchiveAll,
   	None if role.is_authority() => PruningMode::ArchiveAll,
   	None => PruningMode::default(),
   	Some(s) => {
   	if role.is_authority() && !unsafe_pruning {
   	return Err(error::Error::Input(
   	"Validators should run with state pruning disabled (i.e. archive). \
   	You can ignore this check with `--unsafe-pruning`."
   	.to_string(),
   	))
   	}
   	PruningMode::keep_blocks(s.parse().map_err(|_| {
   	error::Error::Input("Invalid pruning mode specified".to_string())
   	})?)
   	},
   	})
   	}

2. Remove --unsafe-pruning cli flag or better make the node fail with an error message that it isn't required anymore:

   substrate/client/cli/src/params/import_params.rs

   Lines 48 to 54 in 293fbeb

   	/// Force start with unsafe pruning settings.
   	///
   	/// When running as a validator it is highly recommended to disable state
   	/// pruning (i.e. 'archive') which is the default. The node will refuse to
   	/// start as a validator if pruning is enabled unless this option is set.
   	#[clap(long)]
   	pub unsafe_pruning: bool,

3. Old nodes should continue to work without requiring to resync or anything. Meaning we should maybe introduce some new PrunningMode::Auto or whatever that ensures that validators that are still running with archive mode continue in archive mode. Any new started validator with a new db should start with a pruned db.

   substrate/client/state-db/src/lib.rs

   Lines 267 to 278 in 293fbeb

   	fn check_meta<D: MetaDb>(mode: &PruningMode, db: &D) -> Result<(), Error<D::Error>> {
   	let db_mode = db.get_meta(&to_meta_key(PRUNING_MODE, &())).map_err(Error::Db)?;
   	trace!(target: "state-db",
   	"DB pruning mode: {:?}",
   	db_mode.as_ref().map(|v| std::str::from_utf8(&v))
   	);
   	match &db_mode {
   	Some(v) if v.as_slice() == mode.id() => Ok(()),
   	Some(v) => Err(Error::InvalidPruningMode(String::from_utf8_lossy(v).into())),
   	None => Ok(()),
   	}
   	}

   here we check that the pruning modes are matching.

[mmyyrroonn]

Hi. @RGafiyatullin I have a question here and hope you can shed some light on this. If all validators and watchers in the network are running in the pruned mode, for a new coming node(validator or watcher), is it able to sync the chain from scratch?

[bkchr]

Yes, pruning here is only about the state, not the blocks.

[mmyyrroonn]

Yes, pruning here is only about the state, not the blocks.

oh. Thank you very much! Good to know

[RGafiyatullin]

The --unsafe-pruning emits an obsoletion-warning on the startup now.

This CLI-argument should be completely removed in some future release.

[RGafiyatullin]

That will remove the CLI-argument completely.

For now it is left as an acceptable CLI-argument in order not to break the existing scripts that may launch the substrate.