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core/rawdb: freezer batch write (#23462)
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This change is a rewrite of the freezer code.

When writing ancient chain data to the freezer, the previous version first encoded each
individual item to a temporary buffer, then wrote the buffer. For small item sizes (for
example, in the block hash freezer table), this strategy causes a lot of system calls for
writing tiny chunks of data. It also allocated a lot of temporary []byte buffers.

In the new version, we instead encode multiple items into a re-useable batch buffer, which
is then written to the file all at once. This avoids performing a system call for every
inserted item.

To make the internal batching work, the ancient database API had to be changed. While
integrating this new API in BlockChain.InsertReceiptChain, additional optimizations were
also added there.

Co-authored-by: Felix Lange <fjl@twurst.com>
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@holiman @fjl
holiman and fjl committed Sep 7, 2021
1 parent 9a0df80 commit 794c613
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Showing 13 changed files with 1,350 additions and 591 deletions.
199 changes: 82 additions & 117 deletions core/blockchain.go
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Expand Up @@ -207,8 +207,7 @@ type BlockChain struct {
processor Processor // Block transaction processor interface
vmConfig vm.Config

shouldPreserve func(*types.Block) bool // Function used to determine whether should preserve the given block.
terminateInsert func(common.Hash, uint64) bool // Testing hook used to terminate ancient receipt chain insertion.
shouldPreserve func(*types.Block) bool // Function used to determine whether should preserve the given block.
}

// NewBlockChain returns a fully initialised block chain using information
Expand Down Expand Up @@ -1085,38 +1084,6 @@ const (
SideStatTy
)

// truncateAncient rewinds the blockchain to the specified header and deletes all
// data in the ancient store that exceeds the specified header.
func (bc *BlockChain) truncateAncient(head uint64) error {
frozen, err := bc.db.Ancients()
if err != nil {
return err
}
// Short circuit if there is no data to truncate in ancient store.
if frozen <= head+1 {
return nil
}
// Truncate all the data in the freezer beyond the specified head
if err := bc.db.TruncateAncients(head + 1); err != nil {
return err
}
// Clear out any stale content from the caches
bc.hc.headerCache.Purge()
bc.hc.tdCache.Purge()
bc.hc.numberCache.Purge()

// Clear out any stale content from the caches
bc.bodyCache.Purge()
bc.bodyRLPCache.Purge()
bc.receiptsCache.Purge()
bc.blockCache.Purge()
bc.txLookupCache.Purge()
bc.futureBlocks.Purge()

log.Info("Rewind ancient data", "number", head)
return nil
}

// numberHash is just a container for a number and a hash, to represent a block
type numberHash struct {
number uint64
Expand Down Expand Up @@ -1155,12 +1122,14 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
var (
stats = struct{ processed, ignored int32 }{}
start = time.Now()
size = 0
size = int64(0)
)

// updateHead updates the head fast sync block if the inserted blocks are better
// and returns an indicator whether the inserted blocks are canonical.
updateHead := func(head *types.Block) bool {
bc.chainmu.Lock()
defer bc.chainmu.Unlock()

// Rewind may have occurred, skip in that case.
if bc.CurrentHeader().Number.Cmp(head.Number()) >= 0 {
Expand All @@ -1169,127 +1138,122 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
rawdb.WriteHeadFastBlockHash(bc.db, head.Hash())
bc.currentFastBlock.Store(head)
headFastBlockGauge.Update(int64(head.NumberU64()))
bc.chainmu.Unlock()
return true
}
}
bc.chainmu.Unlock()
return false
}

// writeAncient writes blockchain and corresponding receipt chain into ancient store.
//
// this function only accepts canonical chain data. All side chain will be reverted
// eventually.
writeAncient := func(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
var (
previous = bc.CurrentFastBlock()
batch = bc.db.NewBatch()
)
// If any error occurs before updating the head or we are inserting a side chain,
// all the data written this time wll be rolled back.
defer func() {
if previous != nil {
if err := bc.truncateAncient(previous.NumberU64()); err != nil {
log.Crit("Truncate ancient store failed", "err", err)
}
}
}()
var deleted []*numberHash
for i, block := range blockChain {
// Short circuit insertion if shutting down or processing failed
if bc.insertStopped() {
return 0, errInsertionInterrupted
}
// Short circuit insertion if it is required(used in testing only)
if bc.terminateInsert != nil && bc.terminateInsert(block.Hash(), block.NumberU64()) {
return i, errors.New("insertion is terminated for testing purpose")
}
// Short circuit if the owner header is unknown
if !bc.HasHeader(block.Hash(), block.NumberU64()) {
return i, fmt.Errorf("containing header #%d [%x..] unknown", block.Number(), block.Hash().Bytes()[:4])
}
if block.NumberU64() == 1 {
// Make sure to write the genesis into the freezer
if frozen, _ := bc.db.Ancients(); frozen == 0 {
h := rawdb.ReadCanonicalHash(bc.db, 0)
b := rawdb.ReadBlock(bc.db, h, 0)
size += rawdb.WriteAncientBlock(bc.db, b, rawdb.ReadReceipts(bc.db, h, 0, bc.chainConfig), rawdb.ReadTd(bc.db, h, 0))
log.Info("Wrote genesis to ancients")
first := blockChain[0]
last := blockChain[len(blockChain)-1]

// Ensure genesis is in ancients.
if first.NumberU64() == 1 {
if frozen, _ := bc.db.Ancients(); frozen == 0 {
b := bc.genesisBlock
td := bc.genesisBlock.Difficulty()
writeSize, err := rawdb.WriteAncientBlocks(bc.db, []*types.Block{b}, []types.Receipts{nil}, td)
size += writeSize
if err != nil {
log.Error("Error writing genesis to ancients", "err", err)
return 0, err
}
log.Info("Wrote genesis to ancients")
}
// Flush data into ancient database.
size += rawdb.WriteAncientBlock(bc.db, block, receiptChain[i], bc.GetTd(block.Hash(), block.NumberU64()))

// Write tx indices if any condition is satisfied:
// * If user requires to reserve all tx indices(txlookuplimit=0)
// * If all ancient tx indices are required to be reserved(txlookuplimit is even higher than ancientlimit)
// * If block number is large enough to be regarded as a recent block
// It means blocks below the ancientLimit-txlookupLimit won't be indexed.
//
// But if the `TxIndexTail` is not nil, e.g. Geth is initialized with
// an external ancient database, during the setup, blockchain will start
// a background routine to re-indexed all indices in [ancients - txlookupLimit, ancients)
// range. In this case, all tx indices of newly imported blocks should be
// generated.
}
// Before writing the blocks to the ancients, we need to ensure that
// they correspond to the what the headerchain 'expects'.
// We only check the last block/header, since it's a contiguous chain.
if !bc.HasHeader(last.Hash(), last.NumberU64()) {
return 0, fmt.Errorf("containing header #%d [%x..] unknown", last.Number(), last.Hash().Bytes()[:4])
}

// Write all chain data to ancients.
td := bc.GetTd(first.Hash(), first.NumberU64())
writeSize, err := rawdb.WriteAncientBlocks(bc.db, blockChain, receiptChain, td)
size += writeSize
if err != nil {
log.Error("Error importing chain data to ancients", "err", err)
return 0, err
}

// Write tx indices if any condition is satisfied:
// * If user requires to reserve all tx indices(txlookuplimit=0)
// * If all ancient tx indices are required to be reserved(txlookuplimit is even higher than ancientlimit)
// * If block number is large enough to be regarded as a recent block
// It means blocks below the ancientLimit-txlookupLimit won't be indexed.
//
// But if the `TxIndexTail` is not nil, e.g. Geth is initialized with
// an external ancient database, during the setup, blockchain will start
// a background routine to re-indexed all indices in [ancients - txlookupLimit, ancients)
// range. In this case, all tx indices of newly imported blocks should be
// generated.
var batch = bc.db.NewBatch()
for _, block := range blockChain {
if bc.txLookupLimit == 0 || ancientLimit <= bc.txLookupLimit || block.NumberU64() >= ancientLimit-bc.txLookupLimit {
rawdb.WriteTxLookupEntriesByBlock(batch, block)
} else if rawdb.ReadTxIndexTail(bc.db) != nil {
rawdb.WriteTxLookupEntriesByBlock(batch, block)
}
stats.processed++
}

// Flush all tx-lookup index data.
size += batch.ValueSize()
size += int64(batch.ValueSize())
if err := batch.Write(); err != nil {
// The tx index data could not be written.
// Roll back the ancient store update.
fastBlock := bc.CurrentFastBlock().NumberU64()
if err := bc.db.TruncateAncients(fastBlock + 1); err != nil {
log.Error("Can't truncate ancient store after failed insert", "err", err)
}
return 0, err
}
batch.Reset()

// Sync the ancient store explicitly to ensure all data has been flushed to disk.
if err := bc.db.Sync(); err != nil {
return 0, err
}
if !updateHead(blockChain[len(blockChain)-1]) {
return 0, errors.New("side blocks can't be accepted as the ancient chain data")
}
previous = nil // disable rollback explicitly

// Wipe out canonical block data.
for _, nh := range deleted {
rawdb.DeleteBlockWithoutNumber(batch, nh.hash, nh.number)
rawdb.DeleteCanonicalHash(batch, nh.number)
}
for _, block := range blockChain {
// Always keep genesis block in active database.
if block.NumberU64() != 0 {
rawdb.DeleteBlockWithoutNumber(batch, block.Hash(), block.NumberU64())
rawdb.DeleteCanonicalHash(batch, block.NumberU64())
// Update the current fast block because all block data is now present in DB.
previousFastBlock := bc.CurrentFastBlock().NumberU64()
if !updateHead(blockChain[len(blockChain)-1]) {
// We end up here if the header chain has reorg'ed, and the blocks/receipts
// don't match the canonical chain.
if err := bc.db.TruncateAncients(previousFastBlock + 1); err != nil {
log.Error("Can't truncate ancient store after failed insert", "err", err)
}
return 0, errSideChainReceipts
}
if err := batch.Write(); err != nil {
return 0, err
}
batch.Reset()

// Wipe out side chain too.
for _, nh := range deleted {
for _, hash := range rawdb.ReadAllHashes(bc.db, nh.number) {
rawdb.DeleteBlock(batch, hash, nh.number)
// Delete block data from the main database.
batch.Reset()
canonHashes := make(map[common.Hash]struct{})
for _, block := range blockChain {
canonHashes[block.Hash()] = struct{}{}
if block.NumberU64() == 0 {
continue
}
rawdb.DeleteCanonicalHash(batch, block.NumberU64())
rawdb.DeleteBlockWithoutNumber(batch, block.Hash(), block.NumberU64())
}
for _, block := range blockChain {
// Always keep genesis block in active database.
if block.NumberU64() != 0 {
for _, hash := range rawdb.ReadAllHashes(bc.db, block.NumberU64()) {
rawdb.DeleteBlock(batch, hash, block.NumberU64())
}
// Delete side chain hash-to-number mappings.
for _, nh := range rawdb.ReadAllHashesInRange(bc.db, first.NumberU64(), last.NumberU64()) {
if _, canon := canonHashes[nh.Hash]; !canon {
rawdb.DeleteHeader(batch, nh.Hash, nh.Number)
}
}
if err := batch.Write(); err != nil {
return 0, err
}
return 0, nil
}

// writeLive writes blockchain and corresponding receipt chain into active store.
writeLive := func(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
skipPresenceCheck := false
Expand Down Expand Up @@ -1327,7 +1291,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
if err := batch.Write(); err != nil {
return 0, err
}
size += batch.ValueSize()
size += int64(batch.ValueSize())
batch.Reset()
}
stats.processed++
Expand All @@ -1336,14 +1300,15 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
// we can ensure all components of body is completed(body, receipts,
// tx indexes)
if batch.ValueSize() > 0 {
size += batch.ValueSize()
size += int64(batch.ValueSize())
if err := batch.Write(); err != nil {
return 0, err
}
}
updateHead(blockChain[len(blockChain)-1])
return 0, nil
}

// Write downloaded chain data and corresponding receipt chain data
if len(ancientBlocks) > 0 {
if n, err := writeAncient(ancientBlocks, ancientReceipts); err != nil {
Expand Down

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