Fixed an issue with forked counters

This commit is contained in:
arkpar 2016-02-05 22:54:33 +01:00
parent 564a191e36
commit f2ed89be46
1 changed files with 64 additions and 26 deletions

View File

@ -20,7 +20,7 @@ use common::*;
use rlp::*;
use hashdb::*;
use memorydb::*;
use rocksdb::{DB, Writable, WriteBatch, IteratorMode};
use rocksdb::{DB, Writable, WriteBatch, IteratorMode, DBVector};
#[cfg(test)]
use std::env;
@ -105,6 +105,11 @@ impl JournalDB {
// for each end_era that we journaled that we are no passing by,
// we remove all of its removes assuming it is canonical and all
// of its inserts otherwise.
//
// we also keep track of the counters for each key inserted in the journal to handle the following cases:
// key K is removed in block A(N) and re-inserted in block B(N + C) (where C < H). K must not be deleted from the DB.
// key K is added in block A(N) and reverted in block B(N + C) (where C < H). K must be deleted
// key K is added in blocks A(N) and A'(N) and is reverted in block B(N + C ) (where C < H). K must not be deleted
// record new commit's details.
let batch = WriteBatch::new();
@ -125,6 +130,7 @@ impl JournalDB {
let mut r = RlpStream::new_list(3);
let inserts: Vec<H256> = self.overlay.keys().iter().filter(|&(_, &c)| c > 0).map(|(key, _)| key.clone()).collect();
// Increase counter for each insrted key no matter if the block is canonical or not.
for i in &inserts {
*counters.entry(i.clone()).or_insert(0) += 1;
}
@ -139,6 +145,7 @@ impl JournalDB {
if let Some((end_era, canon_id)) = end {
let mut index = 0usize;
let mut last;
let mut canon_data: Option<DBVector> = None;
while let Some(rlp_data) = try!(self.backing.get({
let mut r = RlpStream::new_list(2);
r.append(&end_era);
@ -146,35 +153,26 @@ impl JournalDB {
last = r.drain();
&last
})) {
let to_add;
let rlp = Rlp::new(&rlp_data);
{
to_add = rlp.val_at(1);
for i in &to_add {
let delete_counter = {
if let Some(mut cnt) = counters.get_mut(i) {
*cnt -= 1;
*cnt == 0
}
else { false }
};
if delete_counter {
counters.remove(i);
}
}
let canon = {
let rlp = Rlp::new(&rlp_data);
if canon_id != rlp.val_at(0) {
let to_add: Vec<H256> = rlp.val_at(1);
JournalDB::apply_removes(&to_add, &to_add, &mut counters, &batch);
false
} else { true }
};
if canon {
canon_data = Some(rlp_data)
}
let to_remove: Vec<H256> = if canon_id == rlp.val_at(0) {rlp.val_at(2)} else {to_add};
for i in &to_remove {
if !counters.contains_key(i) {
batch.delete(&i).expect("Low-level database error. Some issue with your hard disk?");
}
}
try!(batch.delete(&last));
trace!("JournalDB: delete journal for time #{}.{}, (canon was {}): {} entries", end_era, index, canon_id, to_remove.len());
index += 1;
}
// Canon must be commited last to handle a case when counter reaches 0 in a sibling block
if let Some(ref c) = canon_data {
let rlp = Rlp::new(&c);
let deleted = JournalDB::apply_removes(&rlp.val_at::<Vec<H256>>(1), &rlp.val_at::<Vec<H256>>(2), &mut counters, &batch);
trace!("JournalDB: delete journal for time #{}.{}, (canon was {}): {} entries", end_era, index, canon_id, deleted);
}
try!(batch.put(&LAST_ERA_KEY, &encode(&end_era)));
}
@ -200,6 +198,29 @@ impl JournalDB {
Ok(ret)
}
fn apply_removes(added: &[H256], removed: &[H256], counters: &mut HashMap<H256, i32>, batch: &WriteBatch) -> usize {
let mut deleted = 0usize;
// Decrease the counters first
for i in added.iter() {
let delete_counter = {
if let Some(mut cnt) = counters.get_mut(i) {
*cnt -= 1;
*cnt == 0
}
else { false }
};
if delete_counter {
counters.remove(i);
}
}
// Remove only if counter reached zero
for i in removed.iter().filter(|i| !counters.contains_key(i)) {
batch.delete(&i).expect("Low-level database error. Some issue with your hard disk?");
deleted += 1;
}
deleted
}
fn payload(&self, key: &H256) -> Option<Bytes> {
self.backing.get(&key.bytes()).expect("Low-level database error. Some issue with your hard disk?").map(|v| v.to_vec())
}
@ -387,4 +408,21 @@ mod tests {
jdb.commit(3, &b"2".sha3(), Some((0, b"2".sha3()))).unwrap();
assert!(jdb.exists(&foo));
}
#[test]
fn fork_same_key() {
// history is 1
let mut jdb = JournalDB::new_temp();
jdb.commit(0, &b"0".sha3(), None).unwrap();
let foo = jdb.insert(b"foo");
jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
jdb.insert(b"foo");
jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
assert!(jdb.exists(&foo));
jdb.commit(2, &b"2a".sha3(), Some((1, b"1a".sha3()))).unwrap();
assert!(jdb.exists(&foo));
}
}