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https://github.com/chrislusf/seaweedfs
synced 2024-08-26 03:31:07 +02:00
prefetch 2 chunks
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parent
86ce69f709
commit
3345a50d9b
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@ -109,15 +109,13 @@ func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
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func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
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startOffset, remaining := offset, int64(len(p))
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var nextChunk *ChunkView
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var nextChunks []*ChunkView
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for i, chunk := range c.chunkViews {
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if remaining <= 0 {
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break
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}
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if i+1 < len(c.chunkViews) {
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nextChunk = c.chunkViews[i+1]
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} else {
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nextChunk = nil
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nextChunks = c.chunkViews[i+1:]
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}
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if startOffset < chunk.LogicOffset {
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gap := int(chunk.LogicOffset - startOffset)
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@ -135,7 +133,7 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
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}
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// glog.V(4).Infof("read [%d,%d), %d/%d chunk %s [%d,%d)", chunkStart, chunkStop, i, len(c.chunkViews), chunk.FileId, chunk.LogicOffset-chunk.Offset, chunk.LogicOffset-chunk.Offset+int64(chunk.Size))
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bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset
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copied, err := c.readChunkSliceAt(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], chunk, nextChunk, uint64(bufferOffset))
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copied, err := c.readChunkSliceAt(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], chunk, nextChunks, uint64(bufferOffset))
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if err != nil {
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glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
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return copied, err
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@ -162,15 +160,19 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
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}
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func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, nextChunkViews *ChunkView, offset uint64) (n int, err error) {
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func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, nextChunkViews []*ChunkView, offset uint64) (n int, err error) {
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if c.readerPattern.IsRandomMode() {
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return c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), chunkView.LogicOffset == 0)
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}
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n, err = c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), chunkView.LogicOffset == 0)
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if nextChunkViews != nil {
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c.readerCache.MaybeCache(nextChunkViews.FileId, nextChunkViews.CipherKey, nextChunkViews.IsGzipped, int(nextChunkViews.ChunkSize))
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for i, nextChunk := range nextChunkViews {
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if i < 2 {
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c.readerCache.MaybeCache(nextChunk.FileId, nextChunk.CipherKey, nextChunk.IsGzipped, int(nextChunk.ChunkSize))
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} else {
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break
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}
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}
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return
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}
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