ethdb/memorydb, trie: reduced allocations (#28473)

* trie: use pooling of iterator states in iterator

The node iterator burns through a lot of memory while iterating a trie, and a lot of
that can be avoided by using a fairly small pool (max 40 items).

name        old time/op    new time/op    delta
Iterator-8    6.22ms ± 3%    5.40ms ± 6%  -13.18%  (p=0.008 n=5+5)

name        old alloc/op   new alloc/op   delta
Iterator-8    2.36MB ± 0%    1.67MB ± 0%  -29.23%  (p=0.008 n=5+5)

name        old allocs/op  new allocs/op  delta
Iterator-8     37.0k ± 0%     29.8k ± 0%     ~     (p=0.079 n=4+5)

* ethdb/memorydb: avoid one copying of key

By making the transformation from []byte to string at an earlier point,
we save an allocation which otherwise happens later on.

name           old time/op    new time/op    delta
BatchAllocs-8     412µs ± 6%     382µs ± 2%   -7.18%  (p=0.016 n=5+4)

name           old alloc/op   new alloc/op   delta
BatchAllocs-8     480kB ± 0%     490kB ± 0%   +1.93%  (p=0.008 n=5+5)

name           old allocs/op  new allocs/op  delta
BatchAllocs-8     3.03k ± 0%     2.03k ± 0%  -32.98%  (p=0.008 n=5+5)
pull/28526/head
Martin Holst Swende 1 year ago committed by GitHub
parent a75a2d6db6
commit 5bf8769fb0
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GPG Key ID: 4AEE18F83AFDEB23
  1. 14
      ethdb/memorydb/memorydb.go
  2. 18
      ethdb/memorydb/memorydb_test.go
  3. 71
      trie/iterator.go
  4. 12
      trie/iterator_test.go
  5. 2
      trie/sync_test.go

@ -207,7 +207,7 @@ func (db *Database) Len() int {
// keyvalue is a key-value tuple tagged with a deletion field to allow creating // keyvalue is a key-value tuple tagged with a deletion field to allow creating
// memory-database write batches. // memory-database write batches.
type keyvalue struct { type keyvalue struct {
key []byte key string
value []byte value []byte
delete bool delete bool
} }
@ -222,14 +222,14 @@ type batch struct {
// Put inserts the given value into the batch for later committing. // Put inserts the given value into the batch for later committing.
func (b *batch) Put(key, value []byte) error { func (b *batch) Put(key, value []byte) error {
b.writes = append(b.writes, keyvalue{common.CopyBytes(key), common.CopyBytes(value), false}) b.writes = append(b.writes, keyvalue{string(key), common.CopyBytes(value), false})
b.size += len(key) + len(value) b.size += len(key) + len(value)
return nil return nil
} }
// Delete inserts the a key removal into the batch for later committing. // Delete inserts the a key removal into the batch for later committing.
func (b *batch) Delete(key []byte) error { func (b *batch) Delete(key []byte) error {
b.writes = append(b.writes, keyvalue{common.CopyBytes(key), nil, true}) b.writes = append(b.writes, keyvalue{string(key), nil, true})
b.size += len(key) b.size += len(key)
return nil return nil
} }
@ -249,10 +249,10 @@ func (b *batch) Write() error {
} }
for _, keyvalue := range b.writes { for _, keyvalue := range b.writes {
if keyvalue.delete { if keyvalue.delete {
delete(b.db.db, string(keyvalue.key)) delete(b.db.db, keyvalue.key)
continue continue
} }
b.db.db[string(keyvalue.key)] = keyvalue.value b.db.db[keyvalue.key] = keyvalue.value
} }
return nil return nil
} }
@ -267,12 +267,12 @@ func (b *batch) Reset() {
func (b *batch) Replay(w ethdb.KeyValueWriter) error { func (b *batch) Replay(w ethdb.KeyValueWriter) error {
for _, keyvalue := range b.writes { for _, keyvalue := range b.writes {
if keyvalue.delete { if keyvalue.delete {
if err := w.Delete(keyvalue.key); err != nil { if err := w.Delete([]byte(keyvalue.key)); err != nil {
return err return err
} }
continue continue
} }
if err := w.Put(keyvalue.key, keyvalue.value); err != nil { if err := w.Put([]byte(keyvalue.key), keyvalue.value); err != nil {
return err return err
} }
} }

@ -17,6 +17,7 @@
package memorydb package memorydb
import ( import (
"encoding/binary"
"testing" "testing"
"github.com/ethereum/go-ethereum/ethdb" "github.com/ethereum/go-ethereum/ethdb"
@ -30,3 +31,20 @@ func TestMemoryDB(t *testing.T) {
}) })
}) })
} }
// BenchmarkBatchAllocs measures the time/allocs for storing 120 kB of data
func BenchmarkBatchAllocs(b *testing.B) {
b.ReportAllocs()
var key = make([]byte, 20)
var val = make([]byte, 100)
// 120 * 1_000 -> 120_000 == 120kB
for i := 0; i < b.N; i++ {
batch := New().NewBatch()
for j := uint64(0); j < 1000; j++ {
binary.BigEndian.PutUint64(key, j)
binary.BigEndian.PutUint64(val, j)
batch.Put(key, val)
}
batch.Write()
}
}

@ -144,7 +144,8 @@ type nodeIterator struct {
path []byte // Path to the current node path []byte // Path to the current node
err error // Failure set in case of an internal error in the iterator err error // Failure set in case of an internal error in the iterator
resolver NodeResolver // optional node resolver for avoiding disk hits resolver NodeResolver // optional node resolver for avoiding disk hits
pool []*nodeIteratorState // local pool for iteratorstates
} }
// errIteratorEnd is stored in nodeIterator.err when iteration is done. // errIteratorEnd is stored in nodeIterator.err when iteration is done.
@ -172,6 +173,24 @@ func newNodeIterator(trie *Trie, start []byte) NodeIterator {
return it return it
} }
func (it *nodeIterator) putInPool(item *nodeIteratorState) {
if len(it.pool) < 40 {
item.node = nil
it.pool = append(it.pool, item)
}
}
func (it *nodeIterator) getFromPool() *nodeIteratorState {
idx := len(it.pool) - 1
if idx < 0 {
return new(nodeIteratorState)
}
el := it.pool[idx]
it.pool[idx] = nil
it.pool = it.pool[:idx]
return el
}
func (it *nodeIterator) AddResolver(resolver NodeResolver) { func (it *nodeIterator) AddResolver(resolver NodeResolver) {
it.resolver = resolver it.resolver = resolver
} }
@ -423,8 +442,9 @@ func (st *nodeIteratorState) resolve(it *nodeIterator, path []byte) error {
return nil return nil
} }
func findChild(n *fullNode, index int, path []byte, ancestor common.Hash) (node, *nodeIteratorState, []byte, int) { func (it *nodeIterator) findChild(n *fullNode, index int, ancestor common.Hash) (node, *nodeIteratorState, []byte, int) {
var ( var (
path = it.path
child node child node
state *nodeIteratorState state *nodeIteratorState
childPath []byte childPath []byte
@ -433,13 +453,12 @@ func findChild(n *fullNode, index int, path []byte, ancestor common.Hash) (node,
if n.Children[index] != nil { if n.Children[index] != nil {
child = n.Children[index] child = n.Children[index]
hash, _ := child.cache() hash, _ := child.cache()
state = &nodeIteratorState{ state = it.getFromPool()
hash: common.BytesToHash(hash), state.hash = common.BytesToHash(hash)
node: child, state.node = child
parent: ancestor, state.parent = ancestor
index: -1, state.index = -1
pathlen: len(path), state.pathlen = len(path)
}
childPath = append(childPath, path...) childPath = append(childPath, path...)
childPath = append(childPath, byte(index)) childPath = append(childPath, byte(index))
return child, state, childPath, index return child, state, childPath, index
@ -452,7 +471,7 @@ func (it *nodeIterator) nextChild(parent *nodeIteratorState, ancestor common.Has
switch node := parent.node.(type) { switch node := parent.node.(type) {
case *fullNode: case *fullNode:
// Full node, move to the first non-nil child. // Full node, move to the first non-nil child.
if child, state, path, index := findChild(node, parent.index+1, it.path, ancestor); child != nil { if child, state, path, index := it.findChild(node, parent.index+1, ancestor); child != nil {
parent.index = index - 1 parent.index = index - 1
return state, path, true return state, path, true
} }
@ -460,13 +479,12 @@ func (it *nodeIterator) nextChild(parent *nodeIteratorState, ancestor common.Has
// Short node, return the pointer singleton child // Short node, return the pointer singleton child
if parent.index < 0 { if parent.index < 0 {
hash, _ := node.Val.cache() hash, _ := node.Val.cache()
state := &nodeIteratorState{ state := it.getFromPool()
hash: common.BytesToHash(hash), state.hash = common.BytesToHash(hash)
node: node.Val, state.node = node.Val
parent: ancestor, state.parent = ancestor
index: -1, state.index = -1
pathlen: len(it.path), state.pathlen = len(it.path)
}
path := append(it.path, node.Key...) path := append(it.path, node.Key...)
return state, path, true return state, path, true
} }
@ -480,7 +498,7 @@ func (it *nodeIterator) nextChildAt(parent *nodeIteratorState, ancestor common.H
switch n := parent.node.(type) { switch n := parent.node.(type) {
case *fullNode: case *fullNode:
// Full node, move to the first non-nil child before the desired key position // Full node, move to the first non-nil child before the desired key position
child, state, path, index := findChild(n, parent.index+1, it.path, ancestor) child, state, path, index := it.findChild(n, parent.index+1, ancestor)
if child == nil { if child == nil {
// No more children in this fullnode // No more children in this fullnode
return parent, it.path, false return parent, it.path, false
@ -492,7 +510,7 @@ func (it *nodeIterator) nextChildAt(parent *nodeIteratorState, ancestor common.H
} }
// The child is before the seek position. Try advancing // The child is before the seek position. Try advancing
for { for {
nextChild, nextState, nextPath, nextIndex := findChild(n, index+1, it.path, ancestor) nextChild, nextState, nextPath, nextIndex := it.findChild(n, index+1, ancestor)
// If we run out of children, or skipped past the target, return the // If we run out of children, or skipped past the target, return the
// previous one // previous one
if nextChild == nil || bytes.Compare(nextPath, key) >= 0 { if nextChild == nil || bytes.Compare(nextPath, key) >= 0 {
@ -506,13 +524,12 @@ func (it *nodeIterator) nextChildAt(parent *nodeIteratorState, ancestor common.H
// Short node, return the pointer singleton child // Short node, return the pointer singleton child
if parent.index < 0 { if parent.index < 0 {
hash, _ := n.Val.cache() hash, _ := n.Val.cache()
state := &nodeIteratorState{ state := it.getFromPool()
hash: common.BytesToHash(hash), state.hash = common.BytesToHash(hash)
node: n.Val, state.node = n.Val
parent: ancestor, state.parent = ancestor
index: -1, state.index = -1
pathlen: len(it.path), state.pathlen = len(it.path)
}
path := append(it.path, n.Key...) path := append(it.path, n.Key...)
return state, path, true return state, path, true
} }
@ -533,6 +550,8 @@ func (it *nodeIterator) pop() {
it.path = it.path[:last.pathlen] it.path = it.path[:last.pathlen]
it.stack[len(it.stack)-1] = nil it.stack[len(it.stack)-1] = nil
it.stack = it.stack[:len(it.stack)-1] it.stack = it.stack[:len(it.stack)-1]
// last is now unused
it.putInPool(last)
} }
func compareNodes(a, b NodeIterator) int { func compareNodes(a, b NodeIterator) int {

@ -616,3 +616,15 @@ func isTrieNode(scheme string, key, val []byte) (bool, []byte, common.Hash) {
} }
return true, path, hash return true, path, hash
} }
func BenchmarkIterator(b *testing.B) {
diskDb, srcDb, tr, _ := makeTestTrie(rawdb.HashScheme)
root := tr.Hash()
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
if err := checkTrieConsistency(diskDb, srcDb.Scheme(), root, false); err != nil {
b.Fatal(err)
}
}
}

@ -571,7 +571,7 @@ func testIncompleteSync(t *testing.T, scheme string) {
hash := crypto.Keccak256Hash(result.Data) hash := crypto.Keccak256Hash(result.Data)
if hash != root { if hash != root {
addedKeys = append(addedKeys, result.Path) addedKeys = append(addedKeys, result.Path)
addedHashes = append(addedHashes, crypto.Keccak256Hash(result.Data)) addedHashes = append(addedHashes, hash)
} }
} }
// Fetch the next batch to retrieve // Fetch the next batch to retrieve

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