Improve docs on --keep-blocks CLI parameter and related data structures (#11611)

* Improve docs on `--keep-blocks` CLI parameter and related data structures

* Update client/db/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

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

@@ -33,6 +33,8 @@ pub struct PruningParams {
 	/// Specify the number of finalized blocks to keep in the database.
 	///
 	/// Default is to keep all blocks.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	#[clap(long, value_name = "COUNT")]
 	pub keep_blocks: Option<u32>,
 }

substrate/client/db/src/lib.rs

@@ -302,6 +302,8 @@ pub struct DatabaseSettings {
 	/// Where to find the database.
 	pub source: DatabaseSource,
 	/// Block pruning mode.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: KeepBlocks,
 }
 

substrate/client/network/test/src/lib.rs

@@ -667,6 +667,8 @@ impl<B: BlockT> warp_request_handler::WarpSyncProvider<B> for TestWarpSyncProvid
 #[derive(Default)]
 pub struct FullPeerConfig {
 	/// Pruning window size.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: Option<u32>,
 	/// Block announce validator.
 	pub block_announce_validator: Option<Box<dyn BlockAnnounceValidator<Block> + Send + Sync>>,

substrate/client/service/src/config.rs

@@ -77,6 +77,8 @@ pub struct Configuration {
 	/// State pruning settings.
 	pub state_pruning: Option<PruningMode>,
 	/// Number of blocks to keep in the db.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: KeepBlocks,
 	/// Chain configuration.
 	pub chain_spec: Box<dyn ChainSpec>,