120 lines
3.2 KiB
Go
120 lines
3.2 KiB
Go
// Copyright 2023 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package external
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import (
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"context"
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"io"
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"github.com/pingcap/tidb/br/pkg/lightning/log"
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"github.com/pingcap/tidb/br/pkg/storage"
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"go.uber.org/zap"
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"golang.org/x/sync/errgroup"
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)
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// singeFileReader is a concurrent reader for a single file.
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type singeFileReader struct {
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ctx context.Context
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concurrency int
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readBufferSize int
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currentFileOffset int64
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bufferReadOffset int64
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bufferMaxOffset int64
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maxFileOffset int64
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name string
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storage storage.ExternalStorage
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buffer []byte
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}
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// newSingeFileReader creates a new singeFileReader.
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func newSingeFileReader(ctx context.Context, st storage.ExternalStorage, name string, concurrency int, readBufferSize int) (*singeFileReader, error) {
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if st == nil {
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return nil, nil
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}
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if _, ok := st.(*storage.S3Storage); !ok {
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return nil, nil
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}
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maxOffset, err := storage.GetMaxOffset(ctx, st, name)
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if err != nil {
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return nil, err
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}
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return &singeFileReader{
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ctx: ctx,
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concurrency: concurrency,
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readBufferSize: readBufferSize,
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currentFileOffset: 0,
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bufferReadOffset: 0,
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maxFileOffset: maxOffset,
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name: name,
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storage: st,
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buffer: nil,
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}, nil
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}
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// reload reloads the buffer.
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func (r *singeFileReader) reload() error {
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if r.currentFileOffset >= r.maxFileOffset {
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return io.EOF
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}
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eg := errgroup.Group{}
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for i := 0; i < r.concurrency; i++ {
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i := i
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eg.Go(func() error {
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startOffset := r.currentFileOffset + int64(i*r.readBufferSize)
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endOffset := startOffset + int64(r.readBufferSize)
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if endOffset > r.maxFileOffset {
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endOffset = r.maxFileOffset
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}
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if startOffset > endOffset {
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return nil
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}
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_, err := storage.ReadDataInRange(r.ctx, r.storage, r.name, startOffset, r.buffer[i*r.readBufferSize:i*r.readBufferSize+int(endOffset-startOffset)])
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if err != nil {
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log.FromContext(r.ctx).Warn("read meet error", zap.Any("startOffset", startOffset), zap.Any("endOffset", endOffset), zap.Error(err))
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return err
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}
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return nil
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})
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}
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err := eg.Wait()
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if err != nil {
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return err
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}
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if r.currentFileOffset+int64(r.readBufferSize*r.concurrency) > r.maxFileOffset {
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r.bufferMaxOffset = r.maxFileOffset - r.currentFileOffset
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r.currentFileOffset = r.maxFileOffset
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} else {
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r.bufferMaxOffset = int64(r.readBufferSize * r.concurrency)
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r.currentFileOffset += int64(r.readBufferSize * r.concurrency)
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}
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r.bufferReadOffset = 0
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return nil
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}
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// next returns the next n bytes.
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func (r *singeFileReader) next(n int) []byte {
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end := min(r.bufferReadOffset+int64(n), r.bufferMaxOffset)
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ret := r.buffer[r.bufferReadOffset:end]
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r.bufferReadOffset += int64(len(ret))
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return ret
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}
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