plugeth/core/rawdb/freezer_batch.go

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// Copyright 2021 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 rawdb
import (
"fmt"
"sync/atomic"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/rlp"
"github.com/golang/snappy"
)
// This is the maximum amount of data that will be buffered in memory
// for a single freezer table batch.
const freezerBatchBufferLimit = 2 * 1024 * 1024
// freezerBatch is a write operation of multiple items on a freezer.
type freezerBatch struct {
tables map[string]*freezerTableBatch
}
func newFreezerBatch(f *freezer) *freezerBatch {
batch := &freezerBatch{tables: make(map[string]*freezerTableBatch, len(f.tables))}
for kind, table := range f.tables {
batch.tables[kind] = table.newBatch()
}
return batch
}
// Append adds an RLP-encoded item of the given kind.
func (batch *freezerBatch) Append(kind string, num uint64, item interface{}) error {
PluginTrackUpdate(num, kind, item)
return batch.tables[kind].Append(num, item)
}
// AppendRaw adds an item of the given kind.
func (batch *freezerBatch) AppendRaw(kind string, num uint64, item []byte) error {
PluginTrackUpdate(num, kind, item)
return batch.tables[kind].AppendRaw(num, item)
}
// reset initializes the batch.
func (batch *freezerBatch) reset() {
for _, tb := range batch.tables {
tb.reset()
}
}
// commit is called at the end of a write operation and
// writes all remaining data to tables.
func (batch *freezerBatch) commit() (item uint64, writeSize int64, err error) {
// Check that count agrees on all batches.
item = uint64(math.MaxUint64)
for name, tb := range batch.tables {
if item < math.MaxUint64 && tb.curItem != item {
return 0, 0, fmt.Errorf("table %s is at item %d, want %d", name, tb.curItem, item)
}
item = tb.curItem
}
// Commit all table batches.
for _, tb := range batch.tables {
if err := tb.commit(); err != nil {
return 0, 0, err
}
writeSize += tb.totalBytes
}
return item, writeSize, nil
}
// freezerTableBatch is a batch for a freezer table.
type freezerTableBatch struct {
t *freezerTable
sb *snappyBuffer
encBuffer writeBuffer
dataBuffer []byte
indexBuffer []byte
curItem uint64 // expected index of next append
totalBytes int64 // counts written bytes since reset
}
// newBatch creates a new batch for the freezer table.
func (t *freezerTable) newBatch() *freezerTableBatch {
batch := &freezerTableBatch{t: t}
if !t.noCompression {
batch.sb = new(snappyBuffer)
}
batch.reset()
return batch
}
// reset clears the batch for reuse.
func (batch *freezerTableBatch) reset() {
batch.dataBuffer = batch.dataBuffer[:0]
batch.indexBuffer = batch.indexBuffer[:0]
batch.curItem = atomic.LoadUint64(&batch.t.items)
batch.totalBytes = 0
}
// Append rlp-encodes and adds data at the end of the freezer table. The item number is a
// precautionary parameter to ensure data correctness, but the table will reject already
// existing data.
func (batch *freezerTableBatch) Append(item uint64, data interface{}) error {
if item != batch.curItem {
return fmt.Errorf("%w: have %d want %d", errOutOrderInsertion, item, batch.curItem)
}
// Encode the item.
batch.encBuffer.Reset()
if err := rlp.Encode(&batch.encBuffer, data); err != nil {
return err
}
encItem := batch.encBuffer.data
if batch.sb != nil {
encItem = batch.sb.compress(encItem)
}
return batch.appendItem(encItem)
}
// AppendRaw injects a binary blob at the end of the freezer table. The item number is a
// precautionary parameter to ensure data correctness, but the table will reject already
// existing data.
func (batch *freezerTableBatch) AppendRaw(item uint64, blob []byte) error {
if item != batch.curItem {
return fmt.Errorf("%w: have %d want %d", errOutOrderInsertion, item, batch.curItem)
}
encItem := blob
if batch.sb != nil {
encItem = batch.sb.compress(blob)
}
return batch.appendItem(encItem)
}
func (batch *freezerTableBatch) appendItem(data []byte) error {
// Check if item fits into current data file.
itemSize := int64(len(data))
itemOffset := batch.t.headBytes + int64(len(batch.dataBuffer))
if itemOffset+itemSize > int64(batch.t.maxFileSize) {
// It doesn't fit, go to next file first.
if err := batch.commit(); err != nil {
return err
}
if err := batch.t.advanceHead(); err != nil {
return err
}
itemOffset = 0
}
// Put data to buffer.
batch.dataBuffer = append(batch.dataBuffer, data...)
batch.totalBytes += itemSize
// Put index entry to buffer.
entry := indexEntry{filenum: batch.t.headId, offset: uint32(itemOffset + itemSize)}
batch.indexBuffer = entry.append(batch.indexBuffer)
batch.curItem++
return batch.maybeCommit()
}
// maybeCommit writes the buffered data if the buffer is full enough.
func (batch *freezerTableBatch) maybeCommit() error {
if len(batch.dataBuffer) > freezerBatchBufferLimit {
return batch.commit()
}
return nil
}
// commit writes the batched items to the backing freezerTable.
func (batch *freezerTableBatch) commit() error {
// Write data.
_, err := batch.t.head.Write(batch.dataBuffer)
if err != nil {
return err
}
dataSize := int64(len(batch.dataBuffer))
batch.dataBuffer = batch.dataBuffer[:0]
// Write index.
_, err = batch.t.index.Write(batch.indexBuffer)
if err != nil {
return err
}
indexSize := int64(len(batch.indexBuffer))
batch.indexBuffer = batch.indexBuffer[:0]
// Update headBytes of table.
batch.t.headBytes += dataSize
atomic.StoreUint64(&batch.t.items, batch.curItem)
// Update metrics.
batch.t.sizeGauge.Inc(dataSize + indexSize)
batch.t.writeMeter.Mark(dataSize + indexSize)
return nil
}
// snappyBuffer writes snappy in block format, and can be reused. It is
// reset when WriteTo is called.
type snappyBuffer struct {
dst []byte
}
// compress snappy-compresses the data.
func (s *snappyBuffer) compress(data []byte) []byte {
// The snappy library does not care what the capacity of the buffer is,
// but only checks the length. If the length is too small, it will
// allocate a brand new buffer.
// To avoid that, we check the required size here, and grow the size of the
// buffer to utilize the full capacity.
if n := snappy.MaxEncodedLen(len(data)); len(s.dst) < n {
if cap(s.dst) < n {
s.dst = make([]byte, n)
}
s.dst = s.dst[:n]
}
s.dst = snappy.Encode(s.dst, data)
return s.dst
}
// writeBuffer implements io.Writer for a byte slice.
type writeBuffer struct {
data []byte
}
func (wb *writeBuffer) Write(data []byte) (int, error) {
wb.data = append(wb.data, data...)
return len(data), nil
}
func (wb *writeBuffer) Reset() {
wb.data = wb.data[:0]
}