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core: place a cap on reorglogs (#25711)
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This PR makes the event-sending for deleted and new logs happen in batches, to prevent OOM situation due to large reorgs. 

Co-authored-by: Felix Lange <fjl@twurst.com>
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@holiman @fjl
holiman and fjl authored Sep 9, 2022
1 parent 610cf02 commit 389021a
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Showing 2 changed files with 98 additions and 74 deletions.
78 changes: 31 additions & 47 deletions core/blockchain.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2000,21 +2000,6 @@ func (bc *BlockChain) collectLogs(hash common.Hash, removed bool) []*types.Log {
return logs
}

// mergeLogs returns a merged log slice with specified sort order.
func mergeLogs(logs [][]*types.Log, reverse bool) []*types.Log {
var ret []*types.Log
if reverse {
for i := len(logs) - 1; i >= 0; i-- {
ret = append(ret, logs[i]...)
}
} else {
for i := 0; i < len(logs); i++ {
ret = append(ret, logs[i]...)
}
}
return ret
}

// reorg takes two blocks, an old chain and a new chain and will reconstruct the
// blocks and inserts them to be part of the new canonical chain and accumulates
// potential missing transactions and post an event about them.
Expand All @@ -2028,9 +2013,6 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {

deletedTxs []common.Hash
addedTxs []common.Hash

deletedLogs [][]*types.Log
rebirthLogs [][]*types.Log
)
// Reduce the longer chain to the same number as the shorter one
if oldBlock.NumberU64() > newBlock.NumberU64() {
Expand All @@ -2040,12 +2022,6 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
for _, tx := range oldBlock.Transactions() {
deletedTxs = append(deletedTxs, tx.Hash())
}

// Collect deleted logs for notification
logs := bc.collectLogs(oldBlock.Hash(), true)
if len(logs) > 0 {
deletedLogs = append(deletedLogs, logs)
}
}
} else {
// New chain is longer, stash all blocks away for subsequent insertion
Expand All @@ -2072,12 +2048,6 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
for _, tx := range oldBlock.Transactions() {
deletedTxs = append(deletedTxs, tx.Hash())
}

// Collect deleted logs for notification
logs := bc.collectLogs(oldBlock.Hash(), true)
if len(logs) > 0 {
deletedLogs = append(deletedLogs, logs)
}
newChain = append(newChain, newBlock)

// Step back with both chains
Expand Down Expand Up @@ -2151,28 +2121,42 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
log.Crit("Failed to delete useless indexes", "err", err)
}

// Collect the logs
for i := len(newChain) - 1; i >= 1; i-- {
// Collect reborn logs due to chain reorg
logs := bc.collectLogs(newChain[i].Hash(), false)
if len(logs) > 0 {
rebirthLogs = append(rebirthLogs, logs)
// Send out events for logs from the old canon chain, and 'reborn'
// logs from the new canon chain. The number of logs can be very
// high, so the events are sent in batches of size around 512.

// Deleted logs + blocks:
var deletedLogs []*types.Log
for i := len(oldChain) - 1; i >= 0; i-- {
// Also send event for blocks removed from the canon chain.
bc.chainSideFeed.Send(ChainSideEvent{Block: oldChain[i]})

// Collect deleted logs for notification
if logs := bc.collectLogs(oldChain[i].Hash(), true); len(logs) > 0 {
deletedLogs = append(deletedLogs, logs...)
}
if len(deletedLogs) > 512 {
bc.rmLogsFeed.Send(RemovedLogsEvent{deletedLogs})
deletedLogs = nil
}
}
// If any logs need to be fired, do it now. In theory we could avoid creating
// this goroutine if there are no events to fire, but realistcally that only
// ever happens if we're reorging empty blocks, which will only happen on idle
// networks where performance is not an issue either way.
if len(deletedLogs) > 0 {
bc.rmLogsFeed.Send(RemovedLogsEvent{mergeLogs(deletedLogs, true)})
bc.rmLogsFeed.Send(RemovedLogsEvent{deletedLogs})
}
if len(rebirthLogs) > 0 {
bc.logsFeed.Send(mergeLogs(rebirthLogs, false))
}
if len(oldChain) > 0 {
for i := len(oldChain) - 1; i >= 0; i-- {
bc.chainSideFeed.Send(ChainSideEvent{Block: oldChain[i]})

// New logs:
var rebirthLogs []*types.Log
for i := len(newChain) - 1; i >= 1; i-- {
if logs := bc.collectLogs(newChain[i].Hash(), false); len(logs) > 0 {
rebirthLogs = append(rebirthLogs, logs...)
}
if len(rebirthLogs) > 512 {
bc.logsFeed.Send(rebirthLogs)
rebirthLogs = nil
}
}
if len(rebirthLogs) > 0 {
bc.logsFeed.Send(rebirthLogs)
}
return nil
}
Expand Down
94 changes: 67 additions & 27 deletions core/blockchain_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1158,37 +1158,53 @@ func TestLogRebirth(t *testing.T) {
blockchain.SubscribeLogsEvent(newLogCh)
blockchain.SubscribeRemovedLogsEvent(rmLogsCh)

// This chain contains a single log.
genDb, chain, _ := GenerateChainWithGenesis(gspec, engine, 2, func(i int, gen *BlockGen) {
if i == 1 {
tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, gen.header.BaseFee, logCode), signer, key1)
if err != nil {
t.Fatalf("failed to create tx: %v", err)
// This chain contains 10 logs.
genDb, chain, _ := GenerateChainWithGenesis(gspec, engine, 3, func(i int, gen *BlockGen) {
if i < 2 {
for ii := 0; ii < 5; ii++ {
tx, err := types.SignNewTx(key1, signer, &types.LegacyTx{
Nonce: gen.TxNonce(addr1),
GasPrice: gen.header.BaseFee,
Gas: uint64(1000001),
Data: logCode,
})
if err != nil {
t.Fatalf("failed to create tx: %v", err)
}
gen.AddTx(tx)
}
gen.AddTx(tx)
}
})
if _, err := blockchain.InsertChain(chain); err != nil {
t.Fatalf("failed to insert chain: %v", err)
}
checkLogEvents(t, newLogCh, rmLogsCh, 1, 0)
checkLogEvents(t, newLogCh, rmLogsCh, 10, 0)

// Generate long reorg chain containing another log. Inserting the
// chain removes one log and adds one.
_, forkChain, _ := GenerateChainWithGenesis(gspec, engine, 2, func(i int, gen *BlockGen) {
if i == 1 {
tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, gen.header.BaseFee, logCode), signer, key1)
// Generate long reorg chain containing more logs. Inserting the
// chain removes one log and adds four.
_, forkChain, _ := GenerateChainWithGenesis(gspec, engine, 3, func(i int, gen *BlockGen) {
if i == 2 {
// The last (head) block is not part of the reorg-chain, we can ignore it
return
}
for ii := 0; ii < 5; ii++ {
tx, err := types.SignNewTx(key1, signer, &types.LegacyTx{
Nonce: gen.TxNonce(addr1),
GasPrice: gen.header.BaseFee,
Gas: uint64(1000000),
Data: logCode,
})
if err != nil {
t.Fatalf("failed to create tx: %v", err)
}
gen.AddTx(tx)
gen.OffsetTime(-9) // higher block difficulty
}
gen.OffsetTime(-9) // higher block difficulty
})
if _, err := blockchain.InsertChain(forkChain); err != nil {
t.Fatalf("failed to insert forked chain: %v", err)
}
checkLogEvents(t, newLogCh, rmLogsCh, 1, 1)
checkLogEvents(t, newLogCh, rmLogsCh, 10, 10)

// This chain segment is rooted in the original chain, but doesn't contain any logs.
// When inserting it, the canonical chain switches away from forkChain and re-emits
Expand All @@ -1197,7 +1213,7 @@ func TestLogRebirth(t *testing.T) {
if _, err := blockchain.InsertChain(newBlocks); err != nil {
t.Fatalf("failed to insert forked chain: %v", err)
}
checkLogEvents(t, newLogCh, rmLogsCh, 1, 1)
checkLogEvents(t, newLogCh, rmLogsCh, 10, 10)
}

// This test is a variation of TestLogRebirth. It verifies that log events are emitted
Expand Down Expand Up @@ -1252,19 +1268,43 @@ func TestSideLogRebirth(t *testing.T) {

func checkLogEvents(t *testing.T, logsCh <-chan []*types.Log, rmLogsCh <-chan RemovedLogsEvent, wantNew, wantRemoved int) {
t.Helper()

if len(logsCh) != wantNew {
t.Fatalf("wrong number of log events: got %d, want %d", len(logsCh), wantNew)
}
if len(rmLogsCh) != wantRemoved {
t.Fatalf("wrong number of removed log events: got %d, want %d", len(rmLogsCh), wantRemoved)
}
var (
countNew int
countRm int
prev int
)
// Drain events.
for i := 0; i < len(logsCh); i++ {
<-logsCh
for len(logsCh) > 0 {
x := <-logsCh
countNew += len(x)
for _, log := range x {
// We expect added logs to be in ascending order: 0:0, 0:1, 1:0 ...
have := 100*int(log.BlockNumber) + int(log.TxIndex)
if have < prev {
t.Fatalf("Expected new logs to arrive in ascending order (%d < %d)", have, prev)
}
prev = have
}
}
prev = 0
for len(rmLogsCh) > 0 {
x := <-rmLogsCh
countRm += len(x.Logs)
for _, log := range x.Logs {
// We expect removed logs to be in ascending order: 0:0, 0:1, 1:0 ...
have := 100*int(log.BlockNumber) + int(log.TxIndex)
if have < prev {
t.Fatalf("Expected removed logs to arrive in ascending order (%d < %d)", have, prev)
}
prev = have
}
}

if countNew != wantNew {
t.Fatalf("wrong number of log events: got %d, want %d", countNew, wantNew)
}
for i := 0; i < len(rmLogsCh); i++ {
<-rmLogsCh
if countRm != wantRemoved {
t.Fatalf("wrong number of removed log events: got %d, want %d", countRm, wantRemoved)
}
}

Expand Down

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