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Merge pull request #14522 from ethereum/go-ethereum/chainproc2

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Felix Lange 2017-08-08 13:37:59 +02:00 committed by GitHub
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core/chain_indexer.go Normal file
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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"encoding/binary"
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
)
// ChainIndexerBackend defines the methods needed to process chain segments in
// the background and write the segment results into the database. These can be
// used to create filter blooms or CHTs.
type ChainIndexerBackend interface {
// Reset initiates the processing of a new chain segment, potentially terminating
// any partially completed operations (in case of a reorg).
Reset(section uint64)
// Process crunches through the next header in the chain segment. The caller
// will ensure a sequential order of headers.
Process(header *types.Header)
// Commit finalizes the section metadata and stores it into the database. This
// interface will usually be a batch writer.
Commit(db ethdb.Database) error
}
// ChainIndexer does a post-processing job for equally sized sections of the
// canonical chain (like BlooomBits and CHT structures). A ChainIndexer is
// connected to the blockchain through the event system by starting a
// ChainEventLoop in a goroutine.
//
// Further child ChainIndexers can be added which use the output of the parent
// section indexer. These child indexers receive new head notifications only
// after an entire section has been finished or in case of rollbacks that might
// affect already finished sections.
type ChainIndexer struct {
chainDb ethdb.Database // Chain database to index the data from
indexDb ethdb.Database // Prefixed table-view of the db to write index metadata into
backend ChainIndexerBackend // Background processor generating the index data content
children []*ChainIndexer // Child indexers to cascade chain updates to
active uint32 // Flag whether the event loop was started
update chan struct{} // Notification channel that headers should be processed
quit chan chan error // Quit channel to tear down running goroutines
sectionSize uint64 // Number of blocks in a single chain segment to process
confirmsReq uint64 // Number of confirmations before processing a completed segment
storedSections uint64 // Number of sections successfully indexed into the database
knownSections uint64 // Number of sections known to be complete (block wise)
cascadedHead uint64 // Block number of the last completed section cascaded to subindexers
throttling time.Duration // Disk throttling to prevent a heavy upgrade from hogging resources
log log.Logger
lock sync.RWMutex
}
// NewChainIndexer creates a new chain indexer to do background processing on
// chain segments of a given size after certain number of confirmations passed.
// The throttling parameter might be used to prevent database thrashing.
func NewChainIndexer(chainDb, indexDb ethdb.Database, backend ChainIndexerBackend, section, confirm uint64, throttling time.Duration, kind string) *ChainIndexer {
c := &ChainIndexer{
chainDb: chainDb,
indexDb: indexDb,
backend: backend,
update: make(chan struct{}, 1),
quit: make(chan chan error),
sectionSize: section,
confirmsReq: confirm,
throttling: throttling,
log: log.New("type", kind),
}
// Initialize database dependent fields and start the updater
c.loadValidSections()
go c.updateLoop()
return c
}
// Start creates a goroutine to feed chain head events into the indexer for
// cascading background processing.
func (c *ChainIndexer) Start(currentHeader *types.Header, eventMux *event.TypeMux) {
go c.eventLoop(currentHeader, eventMux)
}
// Close tears down all goroutines belonging to the indexer and returns any error
// that might have occurred internally.
func (c *ChainIndexer) Close() error {
var errs []error
// Tear down the primary update loop
errc := make(chan error)
c.quit <- errc
if err := <-errc; err != nil {
errs = append(errs, err)
}
// If needed, tear down the secondary event loop
if atomic.LoadUint32(&c.active) != 0 {
c.quit <- errc
if err := <-errc; err != nil {
errs = append(errs, err)
}
}
// Return any failures
switch {
case len(errs) == 0:
return nil
case len(errs) == 1:
return errs[0]
default:
return fmt.Errorf("%v", errs)
}
}
// eventLoop is a secondary - optional - event loop of the indexer which is only
// started for the outermost indexer to push chain head events into a processing
// queue.
func (c *ChainIndexer) eventLoop(currentHeader *types.Header, eventMux *event.TypeMux) {
// Mark the chain indexer as active, requiring an additional teardown
atomic.StoreUint32(&c.active, 1)
// Subscribe to chain head events
sub := eventMux.Subscribe(ChainEvent{})
defer sub.Unsubscribe()
// Fire the initial new head event to start any outstanding processing
c.newHead(currentHeader.Number.Uint64(), false)
var (
prevHeader = currentHeader
prevHash = currentHeader.Hash()
)
for {
select {
case errc := <-c.quit:
// Chain indexer terminating, report no failure and abort
errc <- nil
return
case ev, ok := <-sub.Chan():
// Received a new event, ensure it's not nil (closing) and update
if !ok {
errc := <-c.quit
errc <- nil
return
}
header := ev.Data.(ChainEvent).Block.Header()
if header.ParentHash != prevHash {
c.newHead(FindCommonAncestor(c.chainDb, prevHeader, header).Number.Uint64(), true)
}
c.newHead(header.Number.Uint64(), false)
prevHeader, prevHash = header, header.Hash()
}
}
}
// newHead notifies the indexer about new chain heads and/or reorgs.
func (c *ChainIndexer) newHead(head uint64, reorg bool) {
c.lock.Lock()
defer c.lock.Unlock()
// If a reorg happened, invalidate all sections until that point
if reorg {
// Revert the known section number to the reorg point
changed := head / c.sectionSize
if changed < c.knownSections {
c.knownSections = changed
}
// Revert the stored sections from the database to the reorg point
if changed < c.storedSections {
c.setValidSections(changed)
}
// Update the new head number to te finalized section end and notify children
head = changed * c.sectionSize
if head < c.cascadedHead {
c.cascadedHead = head
for _, child := range c.children {
child.newHead(c.cascadedHead, true)
}
}
return
}
// No reorg, calculate the number of newly known sections and update if high enough
var sections uint64
if head >= c.confirmsReq {
sections = (head + 1 - c.confirmsReq) / c.sectionSize
if sections > c.knownSections {
c.knownSections = sections
select {
case c.update <- struct{}{}:
default:
}
}
}
}
// updateLoop is the main event loop of the indexer which pushes chain segments
// down into the processing backend.
func (c *ChainIndexer) updateLoop() {
var updated time.Time
for {
select {
case errc := <-c.quit:
// Chain indexer terminating, report no failure and abort
errc <- nil
return
case <-c.update:
// Section headers completed (or rolled back), update the index
c.lock.Lock()
if c.knownSections > c.storedSections {
// Periodically print an upgrade log message to the user
if time.Since(updated) > 8*time.Second {
if c.knownSections > c.storedSections+1 {
c.log.Info("Upgrading chain index", "percentage", c.storedSections*100/c.knownSections)
}
updated = time.Now()
}
// Cache the current section count and head to allow unlocking the mutex
section := c.storedSections
var oldHead common.Hash
if section > 0 {
oldHead = c.sectionHead(section - 1)
}
// Process the newly defined section in the background
c.lock.Unlock()
newHead, err := c.processSection(section, oldHead)
c.lock.Lock()
// If processing succeeded and no reorgs occcurred, mark the section completed
if err == nil && oldHead == c.sectionHead(section-1) {
c.setSectionHead(section, newHead)
c.setValidSections(section + 1)
c.cascadedHead = c.storedSections*c.sectionSize - 1
for _, child := range c.children {
c.log.Trace("Cascading chain index update", "head", c.cascadedHead)
child.newHead(c.cascadedHead, false)
}
} else {
// If processing failed, don't retry until further notification
c.log.Debug("Chain index processing failed", "section", section, "err", err)
c.knownSections = c.storedSections
}
}
// If there are still further sections to process, reschedule
if c.knownSections > c.storedSections {
time.AfterFunc(c.throttling, func() {
select {
case c.update <- struct{}{}:
default:
}
})
}
c.lock.Unlock()
}
}
}
// processSection processes an entire section by calling backend functions while
// ensuring the continuity of the passed headers. Since the chain mutex is not
// held while processing, the continuity can be broken by a long reorg, in which
// case the function returns with an error.
func (c *ChainIndexer) processSection(section uint64, lastHead common.Hash) (common.Hash, error) {
c.log.Trace("Processing new chain section", "section", section)
// Reset and partial processing
c.backend.Reset(section)
for number := section * c.sectionSize; number < (section+1)*c.sectionSize; number++ {
hash := GetCanonicalHash(c.chainDb, number)
if hash == (common.Hash{}) {
return common.Hash{}, fmt.Errorf("canonical block #%d unknown", number)
}
header := GetHeader(c.chainDb, hash, number)
if header == nil {
return common.Hash{}, fmt.Errorf("block #%d [%x…] not found", number, hash[:4])
} else if header.ParentHash != lastHead {
return common.Hash{}, fmt.Errorf("chain reorged during section processing")
}
c.backend.Process(header)
lastHead = header.Hash()
}
if err := c.backend.Commit(c.chainDb); err != nil {
return common.Hash{}, err
}
return lastHead, nil
}
// Sections returns the number of processed sections maintained by the indexer
// and also the information about the last header indexed for potential canonical
// verifications.
func (c *ChainIndexer) Sections() (uint64, uint64, common.Hash) {
c.lock.Lock()
defer c.lock.Unlock()
return c.storedSections, c.storedSections*c.sectionSize - 1, c.sectionHead(c.storedSections - 1)
}
// AddChildIndexer adds a child ChainIndexer that can use the output of this one
func (c *ChainIndexer) AddChildIndexer(indexer *ChainIndexer) {
c.lock.Lock()
defer c.lock.Unlock()
c.children = append(c.children, indexer)
// Cascade any pending updates to new children too
if c.storedSections > 0 {
indexer.newHead(c.storedSections*c.sectionSize-1, false)
}
}
// loadValidSections reads the number of valid sections from the index database
// and caches is into the local state.
func (c *ChainIndexer) loadValidSections() {
data, _ := c.indexDb.Get([]byte("count"))
if len(data) == 8 {
c.storedSections = binary.BigEndian.Uint64(data[:])
}
}
// setValidSections writes the number of valid sections to the index database
func (c *ChainIndexer) setValidSections(sections uint64) {
// Set the current number of valid sections in the database
var data [8]byte
binary.BigEndian.PutUint64(data[:], sections)
c.indexDb.Put([]byte("count"), data[:])
// Remove any reorged sections, caching the valids in the mean time
for c.storedSections > sections {
c.storedSections--
c.removeSectionHead(c.storedSections)
}
c.storedSections = sections // needed if new > old
}
// sectionHead retrieves the last block hash of a processed section from the
// index database.
func (c *ChainIndexer) sectionHead(section uint64) common.Hash {
var data [8]byte
binary.BigEndian.PutUint64(data[:], section)
hash, _ := c.indexDb.Get(append([]byte("shead"), data[:]...))
if len(hash) == len(common.Hash{}) {
return common.BytesToHash(hash)
}
return common.Hash{}
}
// setSectionHead writes the last block hash of a processed section to the index
// database.
func (c *ChainIndexer) setSectionHead(section uint64, hash common.Hash) {
var data [8]byte
binary.BigEndian.PutUint64(data[:], section)
c.indexDb.Put(append([]byte("shead"), data[:]...), hash.Bytes())
}
// removeSectionHead removes the reference to a processed section from the index
// database.
func (c *ChainIndexer) removeSectionHead(section uint64) {
var data [8]byte
binary.BigEndian.PutUint64(data[:], section)
c.indexDb.Delete(append([]byte("shead"), data[:]...))
}

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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"fmt"
"math/big"
"math/rand"
"testing"
"time"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
)
// Runs multiple tests with randomized parameters.
func TestChainIndexerSingle(t *testing.T) {
for i := 0; i < 10; i++ {
testChainIndexer(t, 1)
}
}
// Runs multiple tests with randomized parameters and different number of
// chain backends.
func TestChainIndexerWithChildren(t *testing.T) {
for i := 2; i < 8; i++ {
testChainIndexer(t, i)
}
}
// testChainIndexer runs a test with either a single chain indexer or a chain of
// multiple backends. The section size and required confirmation count parameters
// are randomized.
func testChainIndexer(t *testing.T, count int) {
db, _ := ethdb.NewMemDatabase()
defer db.Close()
// Create a chain of indexers and ensure they all report empty
backends := make([]*testChainIndexBackend, count)
for i := 0; i < count; i++ {
var (
sectionSize = uint64(rand.Intn(100) + 1)
confirmsReq = uint64(rand.Intn(10))
)
backends[i] = &testChainIndexBackend{t: t, processCh: make(chan uint64)}
backends[i].indexer = NewChainIndexer(db, ethdb.NewTable(db, string([]byte{byte(i)})), backends[i], sectionSize, confirmsReq, 0, fmt.Sprintf("indexer-%d", i))
defer backends[i].indexer.Close()
if sections, _, _ := backends[i].indexer.Sections(); sections != 0 {
t.Fatalf("Canonical section count mismatch: have %v, want %v", sections, 0)
}
if i > 0 {
backends[i-1].indexer.AddChildIndexer(backends[i].indexer)
}
}
// notify pings the root indexer about a new head or reorg, then expect
// processed blocks if a section is processable
notify := func(headNum, failNum uint64, reorg bool) {
backends[0].indexer.newHead(headNum, reorg)
if reorg {
for _, backend := range backends {
headNum = backend.reorg(headNum)
backend.assertSections()
}
return
}
var cascade bool
for _, backend := range backends {
headNum, cascade = backend.assertBlocks(headNum, failNum)
if !cascade {
break
}
backend.assertSections()
}
}
// inject inserts a new random canonical header into the database directly
inject := func(number uint64) {
header := &types.Header{Number: big.NewInt(int64(number)), Extra: big.NewInt(rand.Int63()).Bytes()}
if number > 0 {
header.ParentHash = GetCanonicalHash(db, number-1)
}
WriteHeader(db, header)
WriteCanonicalHash(db, header.Hash(), number)
}
// Start indexer with an already existing chain
for i := uint64(0); i <= 100; i++ {
inject(i)
}
notify(100, 100, false)
// Add new blocks one by one
for i := uint64(101); i <= 1000; i++ {
inject(i)
notify(i, i, false)
}
// Do a reorg
notify(500, 500, true)
// Create new fork
for i := uint64(501); i <= 1000; i++ {
inject(i)
notify(i, i, false)
}
for i := uint64(1001); i <= 1500; i++ {
inject(i)
}
// Failed processing scenario where less blocks are available than notified
notify(2000, 1500, false)
// Notify about a reorg (which could have caused the missing blocks if happened during processing)
notify(1500, 1500, true)
// Create new fork
for i := uint64(1501); i <= 2000; i++ {
inject(i)
notify(i, i, false)
}
}
// testChainIndexBackend implements ChainIndexerBackend
type testChainIndexBackend struct {
t *testing.T
indexer *ChainIndexer
section, headerCnt, stored uint64
processCh chan uint64
}
// assertSections verifies if a chain indexer has the correct number of section.
func (b *testChainIndexBackend) assertSections() {
// Keep trying for 3 seconds if it does not match
var sections uint64
for i := 0; i < 300; i++ {
sections, _, _ = b.indexer.Sections()
if sections == b.stored {
return
}
time.Sleep(10 * time.Millisecond)
}
b.t.Fatalf("Canonical section count mismatch: have %v, want %v", sections, b.stored)
}
// assertBlocks expects processing calls after new blocks have arrived. If the
// failNum < headNum then we are simulating a scenario where a reorg has happened
// after the processing has started and the processing of a section fails.
func (b *testChainIndexBackend) assertBlocks(headNum, failNum uint64) (uint64, bool) {
var sections uint64
if headNum >= b.indexer.confirmsReq {
sections = (headNum + 1 - b.indexer.confirmsReq) / b.indexer.sectionSize
if sections > b.stored {
// expect processed blocks
for expectd := b.stored * b.indexer.sectionSize; expectd < sections*b.indexer.sectionSize; expectd++ {
if expectd > failNum {
// rolled back after processing started, no more process calls expected
// wait until updating is done to make sure that processing actually fails
var updating bool
for i := 0; i < 300; i++ {
b.indexer.lock.Lock()
updating = b.indexer.knownSections > b.indexer.storedSections
b.indexer.lock.Unlock()
if !updating {
break
}
time.Sleep(10 * time.Millisecond)
}
if updating {
b.t.Fatalf("update did not finish")
}
sections = expectd / b.indexer.sectionSize
break
}
select {
case <-time.After(10 * time.Second):
b.t.Fatalf("Expected processed block #%d, got nothing", expectd)
case processed := <-b.processCh:
if processed != expectd {
b.t.Errorf("Expected processed block #%d, got #%d", expectd, processed)
}
}
}
b.stored = sections
}
}
if b.stored == 0 {
return 0, false
}
return b.stored*b.indexer.sectionSize - 1, true
}
func (b *testChainIndexBackend) reorg(headNum uint64) uint64 {
firstChanged := headNum / b.indexer.sectionSize
if firstChanged < b.stored {
b.stored = firstChanged
}
return b.stored * b.indexer.sectionSize
}
func (b *testChainIndexBackend) Reset(section uint64) {
b.section = section
b.headerCnt = 0
}
func (b *testChainIndexBackend) Process(header *types.Header) {
b.headerCnt++
if b.headerCnt > b.indexer.sectionSize {
b.t.Error("Processing too many headers")
}
//t.processCh <- header.Number.Uint64()
select {
case <-time.After(10 * time.Second):
b.t.Fatal("Unexpected call to Process")
case b.processCh <- header.Number.Uint64():
}
}
func (b *testChainIndexBackend) Commit(db ethdb.Database) error {
if b.headerCnt != b.indexer.sectionSize {
b.t.Error("Not enough headers processed")
}
return nil
}