From b0a9c1e0fa87eb25a729d47af4ae5d1ae3b838b5 Mon Sep 17 00:00:00 2001
From: arkpar <arkady.paronyan@gmail.com>
Date: Sat, 25 Mar 2017 15:25:20 +0100
Subject: [PATCH] Limit by entry count

---
 ethcore/src/snapshot/account.rs | 7 +++----
 ethcore/src/snapshot/mod.rs     | 5 ++++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/ethcore/src/snapshot/account.rs b/ethcore/src/snapshot/account.rs
index 4f80d61ea..b06c220e7 100644
--- a/ethcore/src/snapshot/account.rs
+++ b/ethcore/src/snapshot/account.rs
@@ -63,15 +63,14 @@ impl CodeState {
 
 // walk the account's storage trie, returning an RLP item containing the
 // account properties and the storage.
-pub fn to_fat_rlps(acc: &BasicAccount, acct_db: &AccountDB, used_code: &mut HashSet<H256>, preferred_size: usize) -> Result<Vec<Bytes>, Error> {
-	const AVERAGE_BYTES_PER_STORAGE_ENTRY: usize = 47;
+pub fn to_fat_rlps(acc: &BasicAccount, acct_db: &AccountDB, used_code: &mut HashSet<H256>, max_storage_items: usize) -> Result<Vec<Bytes>, Error> {
 	if acc == &ACC_EMPTY {
 		return Ok(vec![::rlp::NULL_RLP.to_vec()]);
 	}
 
 	let db = TrieDB::new(acct_db, &acc.storage_root)?;
 
-	let chunks = db.iter()?.chunks(preferred_size / AVERAGE_BYTES_PER_STORAGE_ENTRY);
+	let chunks = db.iter()?.chunks(max_storage_items);
 	let pair_chunks = chunks.into_iter().map(|chunk| chunk.collect());
 	pair_chunks.pad_using(1, |_| Vec::new(), ).map(|pairs| {
 		let mut stream = RlpStream::new_list(pairs.len());
@@ -253,7 +252,7 @@ mod tests {
 		let thin_rlp = ::rlp::encode(&account);
 		assert_eq!(::rlp::decode::<BasicAccount>(&thin_rlp), account);
 
-		let fat_rlps = to_fat_rlps(&account, &AccountDB::new(db.as_hashdb(), &addr), &mut Default::default(), 1000).unwrap();
+		let fat_rlps = to_fat_rlps(&account, &AccountDB::new(db.as_hashdb(), &addr), &mut Default::default(), 100).unwrap();
 		let mut root = SHA3_NULL_RLP;
 		let mut restored_account = None;
 		for rlp in fat_rlps {
diff --git a/ethcore/src/snapshot/mod.rs b/ethcore/src/snapshot/mod.rs
index 57d044a47..1241152d0 100644
--- a/ethcore/src/snapshot/mod.rs
+++ b/ethcore/src/snapshot/mod.rs
@@ -83,6 +83,9 @@ mod traits {
 // Try to have chunks be around 4MB (before compression)
 const PREFERRED_CHUNK_SIZE: usize = 4 * 1024 * 1024;
 
+// Try to have chunks be around 4MB (before compression)
+const MAX_STORAGE_ENTRIES_PER_ACCOUNT_RECORD: usize = 80_000;
+
 // How many blocks to include in a snapshot, starting from the head of the chain.
 const SNAPSHOT_BLOCKS: u64 = 30000;
 
@@ -374,7 +377,7 @@ pub fn chunk_state<'a>(db: &HashDB, root: &H256, writer: &Mutex<SnapshotWriter +
 
 		let account_db = AccountDB::from_hash(db, account_key_hash);
 
-		let fat_rlps = account::to_fat_rlps(&account, &account_db, &mut used_code, PREFERRED_CHUNK_SIZE)?;
+		let fat_rlps = account::to_fat_rlps(&account, &account_db, &mut used_code, MAX_STORAGE_ENTRIES_PER_ACCOUNT_RECORD)?;
 		for (i, fat_rlp) in fat_rlps.into_iter().enumerate() {
 			chunker.push(account_key.clone(), fat_rlp, i > 0)?;
 		}