Tweaked snapshot params (#6344)

ethcore/src/engines/null_engine.rs

@@ -62,6 +62,6 @@ impl Engine for NullEngine {
 	}
 
 	fn snapshot_components(&self) -> Option<Box<::snapshot::SnapshotComponents>> {
-		Some(Box::new(::snapshot::PowSnapshot(10000)))
+		Some(Box::new(::snapshot::PowSnapshot::new(10000, 10000)))
 	}
 }

ethcore/src/ethereum/ethash.rs

@@ -39,7 +39,10 @@ pub const PARITY_GAS_LIMIT_DETERMINANT: U256 = U256([37, 0, 0, 0]);
 
 /// Number of blocks in an ethash snapshot.
 // make dependent on difficulty incrment divisor?
-const SNAPSHOT_BLOCKS: u64 = 30000;
+const SNAPSHOT_BLOCKS: u64 = 5000;
+/// Maximum number of blocks allowed in an ethash snapshot.
+const MAX_SNAPSHOT_BLOCKS: u64 = 30000;
+
 
 /// Ethash params.
 #[derive(Debug, PartialEq)]
@@ -407,7 +410,7 @@ impl Engine for Arc<Ethash> {
 	}
 
 	fn snapshot_components(&self) -> Option<Box<::snapshot::SnapshotComponents>> {
-		Some(Box::new(::snapshot::PowSnapshot(SNAPSHOT_BLOCKS)))
+		Some(Box::new(::snapshot::PowSnapshot::new(SNAPSHOT_BLOCKS, MAX_SNAPSHOT_BLOCKS)))
 	}
 }
 

ethcore/src/snapshot/consensus/work.rs

@@ -37,11 +37,24 @@ use rand::OsRng;
 /// Snapshot creation and restoration for PoW chains.
 /// This includes blocks from the head of the chain as a
 /// loose assurance that the chain is valid.
-///
-/// The field is the number of blocks from the head of the chain
-/// to include in the snapshot.
 #[derive(Clone, Copy, PartialEq)]
-pub struct PowSnapshot(pub u64);
+pub struct PowSnapshot {
+	/// Number of blocks from the head of the chain
+	/// to include in the snapshot.
+	pub blocks: u64,
+	/// Number of to allow in the snapshot when restoring.
+	pub max_restore_blocks: u64,
+}
+
+impl PowSnapshot {
+	/// Create a new instance.
+	pub fn new(blocks: u64, max_restore_blocks: u64) -> PowSnapshot {
+		PowSnapshot {
+			blocks: blocks,
+			max_restore_blocks: max_restore_blocks,
+		}
+	}
+}
 
 impl SnapshotComponents for PowSnapshot {
 	fn chunk_all(
@@ -57,7 +70,7 @@ impl SnapshotComponents for PowSnapshot {
 			current_hash: block_at,
 			writer: chunk_sink,
 			preferred_size: preferred_size,
-		}.chunk_all(self.0)
+		}.chunk_all(self.blocks)
 	}
 
 	fn rebuilder(
@@ -66,7 +79,7 @@ impl SnapshotComponents for PowSnapshot {
 		db: Arc<KeyValueDB>,
 		manifest: &ManifestData,
 	) -> Result<Box<Rebuilder>, ::error::Error> {
-		PowRebuilder::new(chain, db, manifest, self.0).map(|r| Box::new(r) as Box<_>)
+		PowRebuilder::new(chain, db, manifest, self.max_restore_blocks).map(|r| Box::new(r) as Box<_>)
 	}
 
 	fn min_supported_version(&self) -> u64 { ::snapshot::MIN_SUPPORTED_STATE_CHUNK_VERSION }
@@ -218,7 +231,7 @@ impl Rebuilder for PowRebuilder {
 		trace!(target: "snapshot", "restoring block chunk with {} blocks.", item_count - 3);
 
 		if self.fed_blocks + num_blocks > self.snapshot_blocks {
-			return Err(Error::TooManyBlocks(self.snapshot_blocks, self.fed_blocks).into())
+			return Err(Error::TooManyBlocks(self.snapshot_blocks, self.fed_blocks + num_blocks).into())
 		}
 
 		// todo: assert here that these values are consistent with chunks being in order.

ethcore/src/snapshot/tests/proof_of_work.rs

@@ -30,7 +30,7 @@ use util::kvdb::{self, KeyValueDB, DBTransaction};
 use std::sync::Arc;
 use std::sync::atomic::AtomicBool;
 
-const SNAPSHOT_MODE: ::snapshot::PowSnapshot = ::snapshot::PowSnapshot(30000);
+const SNAPSHOT_MODE: ::snapshot::PowSnapshot = ::snapshot::PowSnapshot { blocks: 30000, max_restore_blocks: 30000 };
 
 fn chunk_and_restore(amount: u64) {
 	let mut canon_chain = ChainGenerator::default();

parity/run.rs

@@ -56,7 +56,7 @@ use signer;
 use url;
 
 // how often to take periodic snapshots.
-const SNAPSHOT_PERIOD: u64 = 10000;
+const SNAPSHOT_PERIOD: u64 = 5000;
 
 // how many blocks to wait before starting a periodic snapshot.
 const SNAPSHOT_HISTORY: u64 = 100;

sync/src/chain.rs

@@ -133,7 +133,7 @@ const MAX_TRANSACTION_PACKET_SIZE: usize = 8 * 1024 * 1024;
 // Maximal number of transactions in sent in single packet.
 const MAX_TRANSACTIONS_TO_PROPAGATE: usize = 64;
 // Min number of blocks to be behind for a snapshot sync
-const SNAPSHOT_RESTORE_THRESHOLD: BlockNumber = 100000;
+const SNAPSHOT_RESTORE_THRESHOLD: BlockNumber = 10000;
 const SNAPSHOT_MIN_PEERS: usize = 3;
 
 const STATUS_PACKET: u8 = 0x00;