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checkpointer.go
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checkpointer.go
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package wal
import (
"bufio"
"encoding/binary"
"encoding/hex"
"fmt"
"io"
"os"
"path"
"path/filepath"
"sort"
"strconv"
"strings"
"github.com/docker/go-units"
"github.com/rs/zerolog"
"github.com/rs/zerolog/log"
"golang.org/x/sync/errgroup"
"github.com/onflow/flow-go/ledger"
"github.com/onflow/flow-go/ledger/complete/mtrie"
"github.com/onflow/flow-go/ledger/complete/mtrie/flattener"
"github.com/onflow/flow-go/ledger/complete/mtrie/node"
"github.com/onflow/flow-go/ledger/complete/mtrie/trie"
"github.com/onflow/flow-go/model/bootstrap"
"github.com/onflow/flow-go/module/metrics"
"github.com/onflow/flow-go/module/util"
utilsio "github.com/onflow/flow-go/utils/io"
)
const checkpointFilenamePrefix = "checkpoint."
const (
MagicBytesCheckpointHeader uint16 = 0x2137
MagicBytesCheckpointSubtrie uint16 = 0x2136
MagicBytesCheckpointToptrie uint16 = 0x2135
MagicBytesPayloadHeader uint16 = 0x2138
)
const VersionV1 uint16 = 0x01
// Versions was reset while changing trie format, so now bump it to 3 to avoid conflicts
// Version 3 contains a file checksum for detecting corrupted checkpoint files.
const VersionV3 uint16 = 0x03
// Version 4 contains a footer with node count and trie count (previously in the header).
// Version 4 also reduces checkpoint data size. See EncodeNode() and EncodeTrie() for more details.
const VersionV4 uint16 = 0x04
// Version 5 includes these changes:
// - remove regCount and maxDepth from serialized nodes
// - add allocated register count and size to serialized tries
// - reduce number of bytes used to encode payload value size from 8 bytes to 4 bytes.
// See EncodeNode() and EncodeTrie() for more details.
const VersionV5 uint16 = 0x05
// Version 6 includes these changes:
// - trie nodes are stored in additional 17 checkpoint files, with .0, .1, .2, ... .16 as
// file name extension
const VersionV6 uint16 = 0x06
// MaxVersion is the latest checkpoint version we support.
// Need to update MaxVersion when creating a newer version.
const MaxVersion = VersionV6
const (
encMagicSize = 2
encVersionSize = 2
headerSize = encMagicSize + encVersionSize
encSubtrieCountSize = 2
encNodeCountSize = 8
encTrieCountSize = 2
crc32SumSize = 4
)
// defaultBufioReadSize replaces the default bufio buffer size of 4096 bytes.
// defaultBufioReadSize can be increased to 8KiB, 16KiB, 32KiB, etc. if it
// improves performance on typical EN hardware.
const defaultBufioReadSize = 1024 * 32
// defaultBufioWriteSize replaces the default bufio buffer size of 4096 bytes.
// defaultBufioWriteSize can be increased to 8KiB, 16KiB, 32KiB, etc. if it
// improves performance on typical EN hardware.
const defaultBufioWriteSize = 1024 * 32
type Checkpointer struct {
dir string
wal *DiskWAL
keyByteSize int
forestCapacity int
}
func NewCheckpointer(wal *DiskWAL, keyByteSize int, forestCapacity int) *Checkpointer {
return &Checkpointer{
dir: wal.wal.Dir(),
wal: wal,
keyByteSize: keyByteSize,
forestCapacity: forestCapacity,
}
}
// listCheckpoints returns all the numbers (unsorted) of the checkpoint files, and the number of the last checkpoint.
func (c *Checkpointer) listCheckpoints() ([]int, int, error) {
return ListCheckpoints(c.dir)
}
// ListCheckpoints returns all the numbers of the checkpoint files, and the number of the last checkpoint.
// note, it doesn't include the root checkpoint file
func ListCheckpoints(dir string) ([]int, int, error) {
list := make([]int, 0)
files, err := os.ReadDir(dir)
if err != nil {
return nil, -1, fmt.Errorf("cannot list directory [%s] content: %w", dir, err)
}
last := -1
for _, fn := range files {
fname := fn.Name()
if !strings.HasPrefix(fname, checkpointFilenamePrefix) {
continue
}
justNumber := fname[len(checkpointFilenamePrefix):]
k, err := strconv.Atoi(justNumber)
if err != nil {
continue
}
list = append(list, k)
// the last check point is the one with the highest number
if k > last {
last = k
}
}
return list, last, nil
}
// Checkpoints returns all the numbers of the checkpoint files in asc order.
// note, it doesn't include the root checkpoint file
func (c *Checkpointer) Checkpoints() ([]int, error) {
return Checkpoints(c.dir)
}
// Checkpoints returns all the checkpoint numbers in asc order
func Checkpoints(dir string) ([]int, error) {
list, _, err := ListCheckpoints(dir)
if err != nil {
return nil, fmt.Errorf("could not fetch all checkpoints: %w", err)
}
sort.Ints(list)
return list, nil
}
// LatestCheckpoint returns number of latest checkpoint or -1 if there are no checkpoints
func (c *Checkpointer) LatestCheckpoint() (int, error) {
_, last, err := c.listCheckpoints()
return last, err
}
// NotCheckpointedSegments - returns numbers of segments which are not checkpointed yet,
// or -1, -1 if there are no segments
func (c *Checkpointer) NotCheckpointedSegments() (from, to int, err error) {
latestCheckpoint, err := c.LatestCheckpoint()
if err != nil {
return -1, -1, fmt.Errorf("cannot get last checkpoint: %w", err)
}
first, last, err := c.wal.Segments()
if err != nil {
return -1, -1, fmt.Errorf("cannot get range of segments: %w", err)
}
// there are no segments at all, there is nothing to checkpoint
if first == -1 && last == -1 {
return -1, -1, nil
}
// no checkpoints
if latestCheckpoint == -1 {
return first, last, nil
}
// segments before checkpoint
if last <= latestCheckpoint {
return -1, -1, nil
}
// there is gap between last checkpoint and segments
if last > latestCheckpoint && latestCheckpoint < first-1 {
return -1, -1, fmt.Errorf("gap between last checkpoint and segments")
}
return latestCheckpoint + 1, last, nil
}
// Checkpoint creates new checkpoint stopping at given segment
func (c *Checkpointer) Checkpoint(to int) (err error) {
_, notCheckpointedTo, err := c.NotCheckpointedSegments()
if err != nil {
return fmt.Errorf("cannot get not checkpointed segments: %w", err)
}
latestCheckpoint, err := c.LatestCheckpoint()
if err != nil {
return fmt.Errorf("cannot get latest checkpoint: %w", err)
}
if latestCheckpoint == to {
return nil //nothing to do
}
if notCheckpointedTo < to {
return fmt.Errorf("no segments to checkpoint to %d, latests not checkpointed segment: %d", to, notCheckpointedTo)
}
forest, err := mtrie.NewForest(c.forestCapacity, &metrics.NoopCollector{}, nil)
if err != nil {
return fmt.Errorf("cannot create Forest: %w", err)
}
c.wal.log.Info().Msgf("creating checkpoint %d", to)
err = c.wal.replay(0, to,
func(tries []*trie.MTrie) error {
return forest.AddTries(tries)
},
func(update *ledger.TrieUpdate) error {
_, err := forest.Update(update)
return err
}, func(rootHash ledger.RootHash) error {
return nil
}, true)
if err != nil {
return fmt.Errorf("cannot replay WAL: %w", err)
}
tries, err := forest.GetTries()
if err != nil {
return fmt.Errorf("cannot get forest tries: %w", err)
}
c.wal.log.Info().Msgf("serializing checkpoint %d", to)
fileName := NumberToFilename(to)
err = StoreCheckpointV6SingleThread(tries, c.wal.dir, fileName, c.wal.log)
if err != nil {
return fmt.Errorf("could not create checkpoint for %v: %w", to, err)
}
checkpointFileSize, err := ReadCheckpointFileSize(c.wal.dir, fileName)
if err != nil {
return fmt.Errorf("could not read checkpoint file size: %w", err)
}
c.wal.log.Info().
Str("checkpoint_file_size", units.BytesSize(float64(checkpointFileSize))).
Msgf("created checkpoint %d with %d tries", to, len(tries))
return nil
}
func NumberToFilenamePart(n int) string {
return fmt.Sprintf("%08d", n)
}
func NumberToFilename(n int) string {
return fmt.Sprintf("%s%s", checkpointFilenamePrefix, NumberToFilenamePart(n))
}
func (c *Checkpointer) CheckpointWriter(to int) (io.WriteCloser, error) {
return CreateCheckpointWriterForFile(c.dir, NumberToFilename(to), c.wal.log)
}
func (c *Checkpointer) Dir() string {
return c.dir
}
// CreateCheckpointWriterForFile returns a file writer that will write to a temporary file and then move it to the checkpoint folder by renaming it.
func CreateCheckpointWriterForFile(dir, filename string, logger zerolog.Logger) (io.WriteCloser, error) {
fullname := path.Join(dir, filename)
if utilsio.FileExists(fullname) {
return nil, fmt.Errorf("checkpoint file %s already exists", fullname)
}
tmpFile, err := os.CreateTemp(dir, "writing-chkpnt-*")
if err != nil {
return nil, fmt.Errorf("cannot create temporary file for checkpoint %v: %w", tmpFile, err)
}
writer := bufio.NewWriterSize(tmpFile, defaultBufioWriteSize)
return &SyncOnCloseRenameFile{
logger: logger,
file: tmpFile,
targetName: fullname,
Writer: writer,
}, nil
}
// StoreCheckpointV5 writes the given tries to checkpoint file, and also appends
// a CRC32 file checksum for integrity check.
// Checkpoint file consists of a flattened forest. Specifically, it consists of:
// - a list of encoded nodes, where references to other nodes are by list index.
// - a list of encoded tries, each referencing their respective root node by index.
//
// Referencing to other nodes by index 0 is a special case, meaning nil.
//
// As an important property, the nodes are listed in an order which satisfies
// Descendents-First-Relationship. The Descendents-First-Relationship has the
// following important property:
// When rebuilding the trie from the sequence of nodes, build the trie on the fly,
// as for each node, the children have been previously encountered.
// TODO: evaluate alternatives to CRC32 since checkpoint file is many GB in size.
// TODO: add concurrency if the performance gains are enough to offset complexity.
func StoreCheckpointV5(dir string, fileName string, logger zerolog.Logger, tries ...*trie.MTrie) (
// error
// Note, the above code, which didn't define the name "err" for the returned error, would be wrong,
// beause err needs to be defined in order to be updated by the defer function
errToReturn error,
) {
writer, err := CreateCheckpointWriterForFile(dir, fileName, logger)
if err != nil {
return fmt.Errorf("could not create writer: %w", err)
}
defer func() {
errToReturn = closeAndMergeError(writer, errToReturn)
}()
crc32Writer := NewCRC32Writer(writer)
// Scratch buffer is used as temporary buffer that node can encode into.
// Data in scratch buffer should be copied or used before scratch buffer is used again.
// If the scratch buffer isn't large enough, a new buffer will be allocated.
// However, 4096 bytes will be large enough to handle almost all payloads
// and 100% of interim nodes.
scratch := make([]byte, 1024*4)
// Write header: magic (2 bytes) + version (2 bytes)
header := scratch[:headerSize]
binary.BigEndian.PutUint16(header, MagicBytesCheckpointHeader)
binary.BigEndian.PutUint16(header[encMagicSize:], VersionV5)
_, err = crc32Writer.Write(header)
if err != nil {
return fmt.Errorf("cannot write checkpoint header: %w", err)
}
// Multiple tries might have shared nodes at higher level, However, we don't want to
// seralize duplicated nodes in the checkpoint file. In order to deduplicate, we build
// a map from unique nodes while iterating and seralizing the nodes to the checkpoint file.
//
// The map for deduplication contains all the trie nodes, which uses a lot of memory.
// In fact, we don't have to build a map for all nodes, since there are nodes which
// are never shared. Nodes can only be shared if and only if they are
// on the same path. In other words, nodes on different path won't be shared.
// If we group trie nodes by path, then we have more smaller groups of trie nodes from the same path,
// which might have duplication. And then for each group, we could build a smaller map for deduplication.
// Processing each group sequentially would allow us reduce operational memory.
//
// With this idea in mind, the seralization can be done in two steps:
// 1. serialize nodes in subtries (tries with root at subtrieLevel).
// 2. serialize remaining nodes (from trie root to subtrie root).
// For instance, if there are 3 top tries, and subtrieLevel is 4, then there will be
// (2 ^ 4) * 3 = 48 subtrie root nodes at level 4.
// Then step 1 will seralize the 48 subtrie root nodes into the checkpoint file, and
// then step 2 will seralize the 3 root nodes (level 0) and the interim nodes from level 1 to 3 into
//
// Step 1:
// 1. Find all the subtrie root nodes at subtrieLevel (level 4)
// 2. Group the subtrie by path. Since subtries in different group have different path, they won't have
// child nodes shared. Subtries in the same group might have duplication, we will build a map to deduplicate.
//
// subtrieLevel is number of edges from trie root to subtrie root.
// Trie root is at level 0.
const subtrieLevel = 4
// subtrieCount is number of subtries at subtrieLevel.
const subtrieCount = 1 << subtrieLevel
// since each trie has `subtrieCount` number of subtries at subtrieLevel,
// we create `subtrieCount` number of groups, each group contains all the subtrie root nodes
// subtrieRoots is an array of groups.
// Each group contains the subtrie roots of the same path at subtrieLevel for different tries.
// For example, if subtrieLevel is 4, then
// - subtrieRoots[0] is a list of all subtrie roots at path [0,0,0,0]
// - subtrieRoots[1] is a list of all subtrie roots at path [0,0,0,1]
// - subtrieRoots[subtrieCount-1] is a list of all subtrie roots at path [1,1,1,1]
// subtrie roots in subtrieRoots[0] have the same path, therefore might have shared child nodes.
var subtrieRoots [subtrieCount][]*node.Node
for i := 0; i < len(subtrieRoots); i++ {
subtrieRoots[i] = make([]*node.Node, len(tries))
}
for trieIndex, t := range tries {
// subtries is an array with subtrieCount trie nodes
// in breadth-first order at subtrieLevel of the trie `t`
subtries := getNodesAtLevel(t.RootNode(), subtrieLevel)
for subtrieIndex, subtrieRoot := range subtries {
subtrieRoots[subtrieIndex][trieIndex] = subtrieRoot
}
}
// topLevelNodes contains all unique nodes of given tries
// from root to subtrie root and their index
// (ordered by node traversal sequence).
// Index 0 is a special case with nil node.
topLevelNodes := make(map[*node.Node]uint64, 1<<(subtrieLevel+1))
topLevelNodes[nil] = 0
// nodeCounter is counter for all unique nodes.
// It starts from 1, as 0 marks nil node.
nodeCounter := uint64(1)
// estimatedSubtrieNodeCount is rough estimate of number of nodes in subtrie,
// assuming trie is a full binary tree. estimatedSubtrieNodeCount is used
// to preallocate traversedSubtrieNodes for memory efficiency.
estimatedSubtrieNodeCount := 0
if len(tries) > 0 {
estimatedTrieNodeCount := 2*int(tries[0].AllocatedRegCount()) - 1
estimatedSubtrieNodeCount = estimatedTrieNodeCount / subtrieCount
}
// Serialize subtrie nodes
for i, subTrieRoot := range subtrieRoots {
// traversedSubtrieNodes contains all unique nodes of subtries of the same path and their index.
traversedSubtrieNodes := make(map[*node.Node]uint64, estimatedSubtrieNodeCount)
// Index 0 is a special case with nil node.
traversedSubtrieNodes[nil] = 0
logging := logProgress(fmt.Sprintf("storing %v-th sub trie roots", i), estimatedSubtrieNodeCount, log.Logger)
for _, root := range subTrieRoot {
// Empty trie is always added to forest as starting point and
// empty trie's root is nil. It remains in the forest until evicted
// by trie queue exceeding capacity.
if root == nil {
continue
}
// Note: nodeCounter is to assign an global index to each node in the order of it being seralized
// into the checkpoint file. Therefore, it has to be reused when iterating each subtrie.
// storeUniqueNodes will add the unique visited node into traversedSubtrieNodes with key as the node
// itself, and value as n-th node being seralized in the checkpoint file.
nodeCounter, err = storeUniqueNodes(root, traversedSubtrieNodes, nodeCounter, scratch, crc32Writer, logging)
if err != nil {
return fmt.Errorf("fail to store nodes in step 1 for subtrie root %v: %w", root.Hash(), err)
}
// Save subtrie root node index in topLevelNodes,
// so when traversing top level tries
// (from level 0 to subtrieLevel) using topLevelNodes,
// node iterator skips subtrie as visited nodes.
topLevelNodes[root] = traversedSubtrieNodes[root]
}
}
// Step 2:
// Now all nodes above and include the subtrieLevel have been seralized. We now
// serialize remaining nodes of each trie from root node (level 0) to (subtrieLevel - 1).
for _, t := range tries {
root := t.RootNode()
if root == nil {
continue
}
// if we iterate through the root trie with an empty visited nodes map, then it will iterate through
// all nodes at all levels. In order to skip the nodes above subtrieLevel, since they have been seralized in step 1,
// we will need to pass in a visited nodes map that contains all the subtrie root nodes, which is the topLevelNodes.
// The topLevelNodes was built in step 1, when seralizing each subtrie root nodes.
nodeCounter, err = storeUniqueNodes(root, topLevelNodes, nodeCounter, scratch, crc32Writer, func(uint64) {})
if err != nil {
return fmt.Errorf("fail to store nodes in step 2 for root trie %v: %w", root.Hash(), err)
}
}
// The root tries are seralized at the end of the checkpoint file, so that it's easy to find what tries are
// included.
for _, t := range tries {
rootNode := t.RootNode()
if !t.IsEmpty() && rootNode.Height() != ledger.NodeMaxHeight {
return fmt.Errorf("height of root node must be %d, but is %d",
ledger.NodeMaxHeight, rootNode.Height())
}
// Get root node index
rootIndex, found := topLevelNodes[rootNode]
if !found {
rootHash := t.RootHash()
return fmt.Errorf("internal error: missing node with hash %s", hex.EncodeToString(rootHash[:]))
}
encTrie := flattener.EncodeTrie(t, rootIndex, scratch)
_, err = crc32Writer.Write(encTrie)
if err != nil {
return fmt.Errorf("cannot serialize trie: %w", err)
}
}
// all trie nodes have been seralized into the checkpoint file, now
// write footer with nodes count and tries count.
footer := scratch[:encNodeCountSize+encTrieCountSize]
binary.BigEndian.PutUint64(footer, nodeCounter-1) // -1 to account for 0 node meaning nil
binary.BigEndian.PutUint16(footer[encNodeCountSize:], uint16(len(tries)))
_, err = crc32Writer.Write(footer)
if err != nil {
return fmt.Errorf("cannot write checkpoint footer: %w", err)
}
// Write CRC32 sum of the footer for validation
crc32buf := scratch[:crc32SumSize]
binary.BigEndian.PutUint32(crc32buf, crc32Writer.Crc32())
_, err = writer.Write(crc32buf)
if err != nil {
return fmt.Errorf("cannot write CRC32: %w", err)
}
return nil
}
func logProgress(msg string, estimatedSubtrieNodeCount int, logger zerolog.Logger) func(nodeCounter uint64) {
lg := util.LogProgress(
logger,
util.DefaultLogProgressConfig(
msg,
estimatedSubtrieNodeCount,
),
)
return func(index uint64) {
lg(1)
}
}
// storeUniqueNodes iterates and serializes unique nodes for trie with given root node.
// It also saves unique nodes and node counter in visitedNodes map.
// It returns nodeCounter and error (if any).
func storeUniqueNodes(
root *node.Node,
visitedNodes map[*node.Node]uint64,
nodeCounter uint64,
scratch []byte,
writer io.Writer,
nodeCounterUpdated func(nodeCounter uint64), // for logging estimated progress
) (uint64, error) {
for itr := flattener.NewUniqueNodeIterator(root, visitedNodes); itr.Next(); {
n := itr.Value()
visitedNodes[n] = nodeCounter
nodeCounter++
nodeCounterUpdated(nodeCounter)
var lchildIndex, rchildIndex uint64
if lchild := n.LeftChild(); lchild != nil {
var found bool
lchildIndex, found = visitedNodes[lchild]
if !found {
hash := lchild.Hash()
return 0, fmt.Errorf("internal error: missing node with hash %s", hex.EncodeToString(hash[:]))
}
}
if rchild := n.RightChild(); rchild != nil {
var found bool
rchildIndex, found = visitedNodes[rchild]
if !found {
hash := rchild.Hash()
return 0, fmt.Errorf("internal error: missing node with hash %s", hex.EncodeToString(hash[:]))
}
}
encNode := flattener.EncodeNode(n, lchildIndex, rchildIndex, scratch)
_, err := writer.Write(encNode)
if err != nil {
return 0, fmt.Errorf("cannot serialize node: %w", err)
}
}
return nodeCounter, nil
}
// getNodesAtLevel returns 2^level nodes at given level in breadth-first order.
// It guarantees size and order of returned nodes (nil element if no node at the position).
// For example, given nil root and level 3, getNodesAtLevel returns a slice
// of 2^3 nil elements.
func getNodesAtLevel(root *node.Node, level uint) []*node.Node {
nodes := []*node.Node{root}
nodesLevel := uint(0)
// Use breadth first traversal to get all nodes at given level.
// If a node isn't found, a nil node is used in its place.
for nodesLevel < level {
nextLevel := nodesLevel + 1
nodesAtNextLevel := make([]*node.Node, 1<<nextLevel)
for i, n := range nodes {
if n != nil {
nodesAtNextLevel[i*2] = n.LeftChild()
nodesAtNextLevel[i*2+1] = n.RightChild()
}
}
nodes = nodesAtNextLevel
nodesLevel = nextLevel
}
return nodes
}
func (c *Checkpointer) LoadCheckpoint(checkpoint int) ([]*trie.MTrie, error) {
filepath := path.Join(c.dir, NumberToFilename(checkpoint))
return LoadCheckpoint(filepath, c.wal.log)
}
func (c *Checkpointer) LoadRootCheckpoint() ([]*trie.MTrie, error) {
filepath := path.Join(c.dir, bootstrap.FilenameWALRootCheckpoint)
return LoadCheckpoint(filepath, c.wal.log)
}
func (c *Checkpointer) HasRootCheckpoint() (bool, error) {
return HasRootCheckpoint(c.dir)
}
func HasRootCheckpoint(dir string) (bool, error) {
if _, err := os.Stat(path.Join(dir, bootstrap.FilenameWALRootCheckpoint)); err == nil {
return true, nil
} else if os.IsNotExist(err) {
return false, nil
} else {
return false, err
}
}
func (c *Checkpointer) RemoveCheckpoint(checkpoint int) error {
name := NumberToFilename(checkpoint)
return deleteCheckpointFiles(c.dir, name)
}
func LoadCheckpoint(filepath string, logger zerolog.Logger) (
tries []*trie.MTrie,
errToReturn error) {
file, err := os.Open(filepath)
if err != nil {
return nil, fmt.Errorf("cannot open checkpoint file %s: %w", filepath, err)
}
defer func() {
evictErr := evictFileFromLinuxPageCache(file, false, logger)
if evictErr != nil {
logger.Warn().Msgf("failed to evict file %s from Linux page cache: %s", filepath, evictErr)
// No need to return this error because it's possible to continue normal operations.
}
errToReturn = closeAndMergeError(file, errToReturn)
}()
return readCheckpoint(file, logger)
}
func readCheckpoint(f *os.File, logger zerolog.Logger) ([]*trie.MTrie, error) {
// Read header: magic (2 bytes) + version (2 bytes)
header := make([]byte, headerSize)
_, err := io.ReadFull(f, header)
if err != nil {
return nil, fmt.Errorf("cannot read header: %w", err)
}
// Decode header
magicBytes := binary.BigEndian.Uint16(header)
version := binary.BigEndian.Uint16(header[encMagicSize:])
// Reset offset
_, err = f.Seek(0, io.SeekStart)
if err != nil {
return nil, fmt.Errorf("cannot seek to start of file: %w", err)
}
if magicBytes != MagicBytesCheckpointHeader {
return nil, fmt.Errorf("unknown file format. Magic constant %x does not match expected %x", magicBytes, MagicBytesCheckpointHeader)
}
switch version {
case VersionV1, VersionV3:
return readCheckpointV3AndEarlier(f, version)
case VersionV4:
return readCheckpointV4(f)
case VersionV5:
return readCheckpointV5(f, logger)
case VersionV6:
return readCheckpointV6(f, logger)
default:
return nil, fmt.Errorf("unsupported file version %x", version)
}
}
type nodeWithRegMetrics struct {
n *node.Node
regCount uint64
regSize uint64
}
// readCheckpointV3AndEarlier deserializes checkpoint file (version 3 and earlier) and returns a list of tries.
// Header (magic and version) is verified by the caller.
// This function is for backwards compatibility, not optimized.
func readCheckpointV3AndEarlier(f *os.File, version uint16) ([]*trie.MTrie, error) {
var bufReader io.Reader = bufio.NewReaderSize(f, defaultBufioReadSize)
crcReader := NewCRC32Reader(bufReader)
var reader io.Reader
if version != VersionV3 {
reader = bufReader
} else {
reader = crcReader
}
// Read header (magic + version), node count, and trie count.
header := make([]byte, headerSize+encNodeCountSize+encTrieCountSize)
_, err := io.ReadFull(reader, header)
if err != nil {
return nil, fmt.Errorf("cannot read header: %w", err)
}
// Magic and version are verified by the caller.
// Decode node count and trie count
nodesCount := binary.BigEndian.Uint64(header[headerSize:])
triesCount := binary.BigEndian.Uint16(header[headerSize+encNodeCountSize:])
nodes := make([]nodeWithRegMetrics, nodesCount+1) //+1 for 0 index meaning nil
tries := make([]*trie.MTrie, triesCount)
for i := uint64(1); i <= nodesCount; i++ {
n, regCount, regSize, err := flattener.ReadNodeFromCheckpointV3AndEarlier(reader, func(nodeIndex uint64) (*node.Node, uint64, uint64, error) {
if nodeIndex >= uint64(i) {
return nil, 0, 0, fmt.Errorf("sequence of stored nodes does not satisfy Descendents-First-Relationship")
}
nm := nodes[nodeIndex]
return nm.n, nm.regCount, nm.regSize, nil
})
if err != nil {
return nil, fmt.Errorf("cannot read node %d: %w", i, err)
}
nodes[i].n = n
nodes[i].regCount = regCount
nodes[i].regSize = regSize
}
for i := uint16(0); i < triesCount; i++ {
trie, err := flattener.ReadTrieFromCheckpointV3AndEarlier(reader, func(nodeIndex uint64) (*node.Node, uint64, uint64, error) {
if nodeIndex >= uint64(len(nodes)) {
return nil, 0, 0, fmt.Errorf("sequence of stored nodes doesn't contain node")
}
nm := nodes[nodeIndex]
return nm.n, nm.regCount, nm.regSize, nil
})
if err != nil {
return nil, fmt.Errorf("cannot read trie %d: %w", i, err)
}
tries[i] = trie
}
if version == VersionV3 {
crc32buf := make([]byte, crc32SumSize)
_, err := io.ReadFull(bufReader, crc32buf)
if err != nil {
return nil, fmt.Errorf("cannot read CRC32: %w", err)
}
readCrc32 := binary.BigEndian.Uint32(crc32buf)
calculatedCrc32 := crcReader.Crc32()
if calculatedCrc32 != readCrc32 {
return nil, fmt.Errorf("checkpoint checksum failed! File contains %x but calculated crc32 is %x", readCrc32, calculatedCrc32)
}
}
return tries, nil
}
// readCheckpointV4 decodes checkpoint file (version 4) and returns a list of tries.
// Header (magic and version) is verified by the caller.
// This function is for backwards compatibility.
func readCheckpointV4(f *os.File) ([]*trie.MTrie, error) {
// Scratch buffer is used as temporary buffer that reader can read into.
// Raw data in scratch buffer should be copied or converted into desired
// objects before next Read operation. If the scratch buffer isn't large
// enough, a new buffer will be allocated. However, 4096 bytes will
// be large enough to handle almost all payloads and 100% of interim nodes.
scratch := make([]byte, 1024*4) // must not be less than 1024
// Read footer to get node count and trie count
// footer offset: nodes count (8 bytes) + tries count (2 bytes) + CRC32 sum (4 bytes)
const footerOffset = encNodeCountSize + encTrieCountSize + crc32SumSize
const footerSize = encNodeCountSize + encTrieCountSize // footer doesn't include crc32 sum
// Seek to footer
_, err := f.Seek(-footerOffset, io.SeekEnd)
if err != nil {
return nil, fmt.Errorf("cannot seek to footer: %w", err)
}
footer := scratch[:footerSize]
_, err = io.ReadFull(f, footer)
if err != nil {
return nil, fmt.Errorf("cannot read footer: %w", err)
}
// Decode node count and trie count
nodesCount := binary.BigEndian.Uint64(footer)
triesCount := binary.BigEndian.Uint16(footer[encNodeCountSize:])
// Seek to the start of file
_, err = f.Seek(0, io.SeekStart)
if err != nil {
return nil, fmt.Errorf("cannot seek to start of file: %w", err)
}
var bufReader io.Reader = bufio.NewReaderSize(f, defaultBufioReadSize)
crcReader := NewCRC32Reader(bufReader)
var reader io.Reader = crcReader
// Read header: magic (2 bytes) + version (2 bytes)
// No action is needed for header because it is verified by the caller.
_, err = io.ReadFull(reader, scratch[:headerSize])
if err != nil {
return nil, fmt.Errorf("cannot read header: %w", err)
}
// nodes's element at index 0 is a special, meaning nil .
nodes := make([]nodeWithRegMetrics, nodesCount+1) //+1 for 0 index meaning nil
tries := make([]*trie.MTrie, triesCount)
for i := uint64(1); i <= nodesCount; i++ {
n, regCount, regSize, err := flattener.ReadNodeFromCheckpointV4(reader, scratch, func(nodeIndex uint64) (*node.Node, uint64, uint64, error) {
if nodeIndex >= uint64(i) {
return nil, 0, 0, fmt.Errorf("sequence of stored nodes does not satisfy Descendents-First-Relationship")
}
nm := nodes[nodeIndex]
return nm.n, nm.regCount, nm.regSize, nil
})
if err != nil {
return nil, fmt.Errorf("cannot read node %d: %w", i, err)
}
nodes[i].n = n
nodes[i].regCount = regCount
nodes[i].regSize = regSize
}
for i := uint16(0); i < triesCount; i++ {
trie, err := flattener.ReadTrieFromCheckpointV4(reader, scratch, func(nodeIndex uint64) (*node.Node, uint64, uint64, error) {
if nodeIndex >= uint64(len(nodes)) {
return nil, 0, 0, fmt.Errorf("sequence of stored nodes doesn't contain node")
}
nm := nodes[nodeIndex]
return nm.n, nm.regCount, nm.regSize, nil
})
if err != nil {
return nil, fmt.Errorf("cannot read trie %d: %w", i, err)
}
tries[i] = trie
}
// Read footer again for crc32 computation
// No action is needed.
_, err = io.ReadFull(reader, footer)
if err != nil {
return nil, fmt.Errorf("cannot read footer: %w", err)
}
// Read CRC32
crc32buf := scratch[:crc32SumSize]
_, err = io.ReadFull(bufReader, crc32buf)
if err != nil {
return nil, fmt.Errorf("cannot read CRC32: %w", err)
}
readCrc32 := binary.BigEndian.Uint32(crc32buf)
calculatedCrc32 := crcReader.Crc32()
if calculatedCrc32 != readCrc32 {
return nil, fmt.Errorf("checkpoint checksum failed! File contains %x but calculated crc32 is %x", readCrc32, calculatedCrc32)
}
return tries, nil
}
// readCheckpointV5 decodes checkpoint file (version 5) and returns a list of tries.
// Checkpoint file header (magic and version) are verified by the caller.
func readCheckpointV5(f *os.File, logger zerolog.Logger) ([]*trie.MTrie, error) {
logger.Info().Msgf("reading v5 checkpoint file")
// Scratch buffer is used as temporary buffer that reader can read into.
// Raw data in scratch buffer should be copied or converted into desired
// objects before next Read operation. If the scratch buffer isn't large
// enough, a new buffer will be allocated. However, 4096 bytes will
// be large enough to handle almost all payloads and 100% of interim nodes.
scratch := make([]byte, 1024*4) // must not be less than 1024
// Read footer to get node count and trie count
// footer offset: nodes count (8 bytes) + tries count (2 bytes) + CRC32 sum (4 bytes)
const footerOffset = encNodeCountSize + encTrieCountSize + crc32SumSize
const footerSize = encNodeCountSize + encTrieCountSize // footer doesn't include crc32 sum
// Seek to footer
_, err := f.Seek(-footerOffset, io.SeekEnd)
if err != nil {
return nil, fmt.Errorf("cannot seek to footer: %w", err)
}
footer := scratch[:footerSize]
_, err = io.ReadFull(f, footer)
if err != nil {
return nil, fmt.Errorf("cannot read footer: %w", err)
}
// Decode node count and trie count
nodesCount := binary.BigEndian.Uint64(footer)
triesCount := binary.BigEndian.Uint16(footer[encNodeCountSize:])
// Seek to the start of file
_, err = f.Seek(0, io.SeekStart)
if err != nil {
return nil, fmt.Errorf("cannot seek to start of file: %w", err)
}
var bufReader io.Reader = bufio.NewReaderSize(f, defaultBufioReadSize)
crcReader := NewCRC32Reader(bufReader)
var reader io.Reader = crcReader
// Read header: magic (2 bytes) + version (2 bytes)
// No action is needed for header because it is verified by the caller.
_, err = io.ReadFull(reader, scratch[:headerSize])
if err != nil {
return nil, fmt.Errorf("cannot read header: %w", err)
}
// nodes's element at index 0 is a special, meaning nil .
nodes := make([]*node.Node, nodesCount+1) //+1 for 0 index meaning nil
tries := make([]*trie.MTrie, triesCount)
logging := logProgress("reading trie nodes", int(nodesCount), logger)
for i := uint64(1); i <= nodesCount; i++ {
n, err := flattener.ReadNode(reader, scratch, func(nodeIndex uint64) (*node.Node, error) {
if nodeIndex >= uint64(i) {
return nil, fmt.Errorf("sequence of serialized nodes does not satisfy Descendents-First-Relationship")
}
return nodes[nodeIndex], nil
})
if err != nil {
return nil, fmt.Errorf("cannot read node %d: %w", i, err)
}
nodes[i] = n
logging(i)
}
logger.Info().Msgf("finished loading %v trie nodes, start loading %v tries", nodesCount, triesCount)
for i := uint16(0); i < triesCount; i++ {
trie, err := flattener.ReadTrie(reader, scratch, func(nodeIndex uint64) (*node.Node, error) {
if nodeIndex >= uint64(len(nodes)) {
return nil, fmt.Errorf("sequence of stored nodes doesn't contain node")
}
return nodes[nodeIndex], nil
})
if err != nil {
return nil, fmt.Errorf("cannot read trie %d: %w", i, err)
}
tries[i] = trie
}
// Read footer again for crc32 computation
// No action is needed.
_, err = io.ReadFull(reader, footer)
if err != nil {
return nil, fmt.Errorf("cannot read footer: %w", err)
}