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prefetch 2 chunks

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This commit is contained in:
chrislu 2022-02-26 03:06:17 -08:00
parent 86ce69f709
commit 3345a50d9b
1 changed files with 10 additions and 8 deletions
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18
weed/filer/reader_at.go
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@ -109,15 +109,13 @@ func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
startOffset, remaining := offset, int64(len(p))
var nextChunk *ChunkView
var nextChunks []*ChunkView
for i, chunk := range c.chunkViews {
if remaining <= 0 {
break
}
if i+1 < len(c.chunkViews) {
nextChunk = c.chunkViews[i+1]
} else {
nextChunk = nil
nextChunks = c.chunkViews[i+1:]
}
if startOffset < chunk.LogicOffset {
gap := int(chunk.LogicOffset - startOffset)
@ -135,7 +133,7 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
}
// 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))
bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset
copied, err := c.readChunkSliceAt(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], chunk, nextChunk, uint64(bufferOffset))
copied, err := c.readChunkSliceAt(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], chunk, nextChunks, uint64(bufferOffset))
if err != nil {
glog.Errorf("fetching chunk %+v: %v\n", chunk, err)
return copied, err
@ -162,15 +160,19 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
}
func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, nextChunkViews *ChunkView, offset uint64) (n int, err error) {
func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, nextChunkViews []*ChunkView, offset uint64) (n int, err error) {
if c.readerPattern.IsRandomMode() {
return c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), chunkView.LogicOffset == 0)
}
n, err = c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), chunkView.LogicOffset == 0)
if nextChunkViews != nil {
c.readerCache.MaybeCache(nextChunkViews.FileId, nextChunkViews.CipherKey, nextChunkViews.IsGzipped, int(nextChunkViews.ChunkSize))
for i, nextChunk := range nextChunkViews {
if i < 2 {
c.readerCache.MaybeCache(nextChunk.FileId, nextChunk.CipherKey, nextChunk.IsGzipped, int(nextChunk.ChunkSize))
} else {
break
}
}
return
}