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author | Zahoor Mohamed <zahoor@zahoor.in> | 2017-09-22 04:22:51 +0800 |
---|---|---|
committer | Felix Lange <fjl@users.noreply.github.com> | 2017-09-22 04:22:51 +0800 |
commit | d558a595adf4e89bab5b28ffde1448dc1e5768b0 (patch) | |
tree | 1316cca927bfd4dfc4a8673ae0b9c2f75724f07e /swarm/storage/pyramid.go | |
parent | 3c8656347f67dbc8e57c663ec5c26d24c4151678 (diff) | |
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swarm/storage: pyramid chunker re-write (#14382)
Diffstat (limited to 'swarm/storage/pyramid.go')
-rw-r--r-- | swarm/storage/pyramid.go | 681 |
1 files changed, 559 insertions, 122 deletions
diff --git a/swarm/storage/pyramid.go b/swarm/storage/pyramid.go index 74e00a497..e3be2a987 100644 --- a/swarm/storage/pyramid.go +++ b/swarm/storage/pyramid.go @@ -18,53 +18,112 @@ package storage import ( "encoding/binary" - "fmt" + "errors" "io" - "math" - "strings" "sync" + "time" +) + +/* + The main idea of a pyramid chunker is to process the input data without knowing the entire size apriori. + For this to be achieved, the chunker tree is built from the ground up until the data is exhausted. + This opens up new aveneus such as easy append and other sort of modifications to the tree therby avoiding + duplication of data chunks. + + + Below is an example of a two level chunks tree. The leaf chunks are called data chunks and all the above + chunks are called tree chunks. The tree chunk above data chunks is level 0 and so on until it reaches + the root tree chunk. + + + + T10 <- Tree chunk lvl1 + | + __________________________|_____________________________ + / | | \ + / | \ \ + __T00__ ___T01__ ___T02__ ___T03__ <- Tree chunks lvl 0 + / / \ / / \ / / \ / / \ + / / \ / / \ / / \ / / \ + D1 D2 ... D128 D1 D2 ... D128 D1 D2 ... D128 D1 D2 ... D128 <- Data Chunks + + + The split function continuously read the data and creates data chunks and send them to storage. + When certain no of data chunks are created (defaultBranches), a signal is sent to create a tree + entry. When the level 0 tree entries reaches certain threshold (defaultBranches), another signal + is sent to a tree entry one level up.. and so on... until only the data is exhausted AND only one + tree entry is present in certain level. The key of tree entry is given out as the rootKey of the file. + +*/ + +var ( + errLoadingTreeRootChunk = errors.New("LoadTree Error: Could not load root chunk") + errLoadingTreeChunk = errors.New("LoadTree Error: Could not load chunk") +) - "github.com/ethereum/go-ethereum/common" +const ( + ChunkProcessors = 8 + DefaultBranches int64 = 128 + splitTimeout = time.Minute * 5 ) const ( - processors = 8 + DataChunk = 0 + TreeChunk = 1 ) -type Tree struct { - Chunks int64 - Levels []map[int64]*Node - Lock sync.RWMutex +type ChunkerParams struct { + Branches int64 + Hash string +} + +func NewChunkerParams() *ChunkerParams { + return &ChunkerParams{ + Branches: DefaultBranches, + Hash: SHA3Hash, + } } -type Node struct { - Pending int64 - Size uint64 - Children []common.Hash - Last bool +// Entry to create a tree node +type TreeEntry struct { + level int + branchCount int64 + subtreeSize uint64 + chunk []byte + key []byte + index int // used in append to indicate the index of existing tree entry + updatePending bool // indicates if the entry is loaded from existing tree } -func (self *Node) String() string { - var children []string - for _, node := range self.Children { - children = append(children, node.Hex()) +func NewTreeEntry(pyramid *PyramidChunker) *TreeEntry { + return &TreeEntry{ + level: 0, + branchCount: 0, + subtreeSize: 0, + chunk: make([]byte, pyramid.chunkSize+8), + key: make([]byte, pyramid.hashSize), + index: 0, + updatePending: false, } - return fmt.Sprintf("pending: %v, size: %v, last :%v, children: %v", self.Pending, self.Size, self.Last, strings.Join(children, ", ")) } -type Task struct { - Index int64 // Index of the chunk being processed - Size uint64 - Data []byte // Binary blob of the chunk - Last bool +// Used by the hash processor to create a data/tree chunk and send to storage +type chunkJob struct { + key Key + chunk []byte + size int64 + parentWg *sync.WaitGroup + chunkType int // used to identify the tree related chunks for debugging + chunkLvl int // leaf-1 is level 0 and goes upwards until it reaches root } type PyramidChunker struct { - hashFunc Hasher + hashFunc SwarmHasher chunkSize int64 hashSize int64 branches int64 - workerCount int + workerCount int64 + workerLock sync.RWMutex } func NewPyramidChunker(params *ChunkerParams) (self *PyramidChunker) { @@ -73,128 +132,506 @@ func NewPyramidChunker(params *ChunkerParams) (self *PyramidChunker) { self.branches = params.Branches self.hashSize = int64(self.hashFunc().Size()) self.chunkSize = self.hashSize * self.branches - self.workerCount = 1 + self.workerCount = 0 return } -func (self *PyramidChunker) Split(data io.Reader, size int64, chunkC chan *Chunk, swg, wwg *sync.WaitGroup) (Key, error) { +func (self *PyramidChunker) Join(key Key, chunkC chan *Chunk) LazySectionReader { + return &LazyChunkReader{ + key: key, + chunkC: chunkC, + chunkSize: self.chunkSize, + branches: self.branches, + hashSize: self.hashSize, + } +} - chunks := (size + self.chunkSize - 1) / self.chunkSize - depth := int(math.Ceil(math.Log(float64(chunks))/math.Log(float64(self.branches)))) + 1 +func (self *PyramidChunker) incrementWorkerCount() { + self.workerLock.Lock() + defer self.workerLock.Unlock() + self.workerCount += 1 +} - results := Tree{ - Chunks: chunks, - Levels: make([]map[int64]*Node, depth), +func (self *PyramidChunker) getWorkerCount() int64 { + self.workerLock.Lock() + defer self.workerLock.Unlock() + return self.workerCount +} + +func (self *PyramidChunker) decrementWorkerCount() { + self.workerLock.Lock() + defer self.workerLock.Unlock() + self.workerCount -= 1 +} + +func (self *PyramidChunker) Split(data io.Reader, size int64, chunkC chan *Chunk, storageWG, processorWG *sync.WaitGroup) (Key, error) { + jobC := make(chan *chunkJob, 2*ChunkProcessors) + wg := &sync.WaitGroup{} + errC := make(chan error) + quitC := make(chan bool) + rootKey := make([]byte, self.hashSize) + chunkLevel := make([][]*TreeEntry, self.branches) + + wg.Add(1) + go self.prepareChunks(false, chunkLevel, data, rootKey, quitC, wg, jobC, processorWG, chunkC, errC, storageWG) + + // closes internal error channel if all subprocesses in the workgroup finished + go func() { + + // waiting for all chunks to finish + wg.Wait() + + // if storage waitgroup is non-nil, we wait for storage to finish too + if storageWG != nil { + storageWG.Wait() + } + //We close errC here because this is passed down to 8 parallel routines underneath. + // if a error happens in one of them.. that particular routine raises error... + // once they all complete successfully, the control comes back and we can safely close this here. + close(errC) + }() + + defer close(quitC) + + select { + case err := <-errC: + if err != nil { + return nil, err + } + case <-time.NewTimer(splitTimeout).C: } - for i := 0; i < depth; i++ { - results.Levels[i] = make(map[int64]*Node) + return rootKey, nil + +} + +func (self *PyramidChunker) Append(key Key, data io.Reader, chunkC chan *Chunk, storageWG, processorWG *sync.WaitGroup) (Key, error) { + quitC := make(chan bool) + rootKey := make([]byte, self.hashSize) + chunkLevel := make([][]*TreeEntry, self.branches) + + // Load the right most unfinished tree chunks in every level + self.loadTree(chunkLevel, key, chunkC, quitC) + + jobC := make(chan *chunkJob, 2*ChunkProcessors) + wg := &sync.WaitGroup{} + errC := make(chan error) + + wg.Add(1) + go self.prepareChunks(true, chunkLevel, data, rootKey, quitC, wg, jobC, processorWG, chunkC, errC, storageWG) + + // closes internal error channel if all subprocesses in the workgroup finished + go func() { + + // waiting for all chunks to finish + wg.Wait() + + // if storage waitgroup is non-nil, we wait for storage to finish too + if storageWG != nil { + storageWG.Wait() + } + close(errC) + }() + + defer close(quitC) + + select { + case err := <-errC: + if err != nil { + return nil, err + } + case <-time.NewTimer(splitTimeout).C: } - // Create a pool of workers to crunch through the file - tasks := make(chan *Task, 2*processors) - pend := new(sync.WaitGroup) - abortC := make(chan bool) - for i := 0; i < processors; i++ { - pend.Add(1) - go self.processor(pend, swg, tasks, chunkC, &results) + return rootKey, nil + +} + +func (self *PyramidChunker) processor(id int64, jobC chan *chunkJob, chunkC chan *Chunk, errC chan error, quitC chan bool, swg, wwg *sync.WaitGroup) { + defer self.decrementWorkerCount() + + hasher := self.hashFunc() + if wwg != nil { + defer wwg.Done() } - // Feed the chunks into the task pool - read := 0 - for index := 0; ; index++ { - buffer := make([]byte, self.chunkSize+8) - n, err := data.Read(buffer[8:]) - read += n - last := int64(read) == size || err == io.ErrUnexpectedEOF || err == io.EOF - if err != nil && !last { - close(abortC) - break - } - binary.LittleEndian.PutUint64(buffer[:8], uint64(n)) - pend.Add(1) + for { select { - case tasks <- &Task{Index: int64(index), Size: uint64(n), Data: buffer[:n+8], Last: last}: - case <-abortC: - return nil, err + + case job, ok := <-jobC: + if !ok { + return + } + self.processChunk(id, hasher, job, chunkC, swg) + case <-quitC: + return } - if last { - break + } +} + +func (self *PyramidChunker) processChunk(id int64, hasher SwarmHash, job *chunkJob, chunkC chan *Chunk, swg *sync.WaitGroup) { + hasher.ResetWithLength(job.chunk[:8]) // 8 bytes of length + hasher.Write(job.chunk[8:]) // minus 8 []byte length + h := hasher.Sum(nil) + + newChunk := &Chunk{ + Key: h, + SData: job.chunk, + Size: job.size, + wg: swg, + } + + // report hash of this chunk one level up (keys corresponds to the proper subslice of the parent chunk) + copy(job.key, h) + + // send off new chunk to storage + if chunkC != nil { + if swg != nil { + swg.Add(1) } } - // Wait for the workers and return - close(tasks) - pend.Wait() + job.parentWg.Done() - key := results.Levels[0][0].Children[0][:] - return key, nil + if chunkC != nil { + chunkC <- newChunk + } } -func (self *PyramidChunker) processor(pend, swg *sync.WaitGroup, tasks chan *Task, chunkC chan *Chunk, results *Tree) { - defer pend.Done() +func (self *PyramidChunker) loadTree(chunkLevel [][]*TreeEntry, key Key, chunkC chan *Chunk, quitC chan bool) error { + // Get the root chunk to get the total size + chunk := retrieve(key, chunkC, quitC) + if chunk == nil { + return errLoadingTreeRootChunk + } - // Start processing leaf chunks ad infinitum - hasher := self.hashFunc() - for task := range tasks { - depth, pow := len(results.Levels)-1, self.branches - size := task.Size - data := task.Data - var node *Node - for depth >= 0 { - // New chunk received, reset the hasher and start processing - hasher.Reset() - if node == nil { // Leaf node, hash the data chunk - hasher.Write(task.Data) - } else { // Internal node, hash the children - size = node.Size - data = make([]byte, hasher.Size()*len(node.Children)+8) - binary.LittleEndian.PutUint64(data[:8], size) - - hasher.Write(data[:8]) - for i, hash := range node.Children { - copy(data[i*hasher.Size()+8:], hash[:]) - hasher.Write(hash[:]) + //if data size is less than a chunk... add a parent with update as pending + if chunk.Size <= self.chunkSize { + newEntry := &TreeEntry{ + level: 0, + branchCount: 1, + subtreeSize: uint64(chunk.Size), + chunk: make([]byte, self.chunkSize+8), + key: make([]byte, self.hashSize), + index: 0, + updatePending: true, + } + copy(newEntry.chunk[8:], chunk.Key) + chunkLevel[0] = append(chunkLevel[0], newEntry) + return nil + } + + var treeSize int64 + var depth int + treeSize = self.chunkSize + for ; treeSize < chunk.Size; treeSize *= self.branches { + depth++ + } + + // Add the root chunk entry + branchCount := int64(len(chunk.SData)-8) / self.hashSize + newEntry := &TreeEntry{ + level: int(depth - 1), + branchCount: branchCount, + subtreeSize: uint64(chunk.Size), + chunk: chunk.SData, + key: key, + index: 0, + updatePending: true, + } + chunkLevel[depth-1] = append(chunkLevel[depth-1], newEntry) + + // Add the rest of the tree + for lvl := (depth - 1); lvl >= 1; lvl-- { + + //TODO(jmozah): instead of loading finished branches and then trim in the end, + //avoid loading them in the first place + for _, ent := range chunkLevel[lvl] { + branchCount = int64(len(ent.chunk)-8) / self.hashSize + for i := int64(0); i < branchCount; i++ { + key := ent.chunk[8+(i*self.hashSize) : 8+((i+1)*self.hashSize)] + newChunk := retrieve(key, chunkC, quitC) + if newChunk == nil { + return errLoadingTreeChunk } - } - hash := hasher.Sum(nil) - last := task.Last || (node != nil) && node.Last - // Insert the subresult into the memoization tree - results.Lock.Lock() - if node = results.Levels[depth][task.Index/pow]; node == nil { - // Figure out the pending tasks - pending := self.branches - if task.Index/pow == results.Chunks/pow { - pending = (results.Chunks + pow/self.branches - 1) / (pow / self.branches) % self.branches + bewBranchCount := int64(len(newChunk.SData)-8) / self.hashSize + newEntry := &TreeEntry{ + level: int(lvl - 1), + branchCount: bewBranchCount, + subtreeSize: uint64(newChunk.Size), + chunk: newChunk.SData, + key: key, + index: 0, + updatePending: true, } - node = &Node{pending, 0, make([]common.Hash, pending), last} - results.Levels[depth][task.Index/pow] = node + chunkLevel[lvl-1] = append(chunkLevel[lvl-1], newEntry) + } - node.Pending-- - i := task.Index / (pow / self.branches) % self.branches - if last { - node.Last = true + + // We need to get only the right most unfinished branch.. so trim all finished branches + if int64(len(chunkLevel[lvl-1])) >= self.branches { + chunkLevel[lvl-1] = nil } - copy(node.Children[i][:], hash) - node.Size += size - left := node.Pending - if chunkC != nil { - if swg != nil { - swg.Add(1) - } + } + } + + return nil +} + +func (self *PyramidChunker) prepareChunks(isAppend bool, chunkLevel [][]*TreeEntry, data io.Reader, rootKey []byte, quitC chan bool, wg *sync.WaitGroup, jobC chan *chunkJob, processorWG *sync.WaitGroup, chunkC chan *Chunk, errC chan error, storageWG *sync.WaitGroup) { + defer wg.Done() + + chunkWG := &sync.WaitGroup{} + totalDataSize := 0 - chunkC <- &Chunk{Key: hash, SData: data, wg: swg} - // TODO: consider selecting on self.quitC to avoid blocking forever on shutdown + // processorWG keeps track of workers spawned for hashing chunks + if processorWG != nil { + processorWG.Add(1) + } + + self.incrementWorkerCount() + go self.processor(self.workerCount, jobC, chunkC, errC, quitC, storageWG, processorWG) + + parent := NewTreeEntry(self) + var unFinishedChunk *Chunk + + if isAppend == true && len(chunkLevel[0]) != 0 { + + lastIndex := len(chunkLevel[0]) - 1 + ent := chunkLevel[0][lastIndex] + + if ent.branchCount < self.branches { + parent = &TreeEntry{ + level: 0, + branchCount: ent.branchCount, + subtreeSize: ent.subtreeSize, + chunk: ent.chunk, + key: ent.key, + index: lastIndex, + updatePending: true, } - if depth+1 < len(results.Levels) { - delete(results.Levels[depth+1], task.Index/(pow/self.branches)) + + lastBranch := parent.branchCount - 1 + lastKey := parent.chunk[8+lastBranch*self.hashSize : 8+(lastBranch+1)*self.hashSize] + + unFinishedChunk = retrieve(lastKey, chunkC, quitC) + if unFinishedChunk.Size < self.chunkSize { + + parent.subtreeSize = parent.subtreeSize - uint64(unFinishedChunk.Size) + parent.branchCount = parent.branchCount - 1 + } else { + unFinishedChunk = nil } + } + } - results.Lock.Unlock() - // If there's more work to be done, leave for others - if left > 0 { + for index := 0; ; index++ { + + var n int + var err error + chunkData := make([]byte, self.chunkSize+8) + if unFinishedChunk != nil { + copy(chunkData, unFinishedChunk.SData) + n, err = data.Read(chunkData[8+unFinishedChunk.Size:]) + n += int(unFinishedChunk.Size) + unFinishedChunk = nil + } else { + n, err = data.Read(chunkData[8:]) + } + + totalDataSize += n + if err != nil { + if err == io.EOF || err == io.ErrUnexpectedEOF { + if parent.branchCount == 1 { + // Data is exactly one chunk.. pick the last chunk key as root + chunkWG.Wait() + lastChunksKey := parent.chunk[8 : 8+self.hashSize] + copy(rootKey, lastChunksKey) + break + } + } else { + close(quitC) break } - // We're the last ones in this batch, merge the children together - depth-- - pow *= self.branches } - pend.Done() + + // Data ended in chunk boundry.. just signal to start bulding tree + if n == 0 { + self.buildTree(isAppend, chunkLevel, parent, chunkWG, jobC, quitC, true, rootKey) + break + } else { + + pkey := self.enqueueDataChunk(chunkData, uint64(n), parent, chunkWG, jobC, quitC) + + // update tree related parent data structures + parent.subtreeSize += uint64(n) + parent.branchCount++ + + // Data got exhausted... signal to send any parent tree related chunks + if int64(n) < self.chunkSize { + + // only one data chunk .. so dont add any parent chunk + if parent.branchCount <= 1 { + chunkWG.Wait() + copy(rootKey, pkey) + break + } + + self.buildTree(isAppend, chunkLevel, parent, chunkWG, jobC, quitC, true, rootKey) + break + } + + if parent.branchCount == self.branches { + self.buildTree(isAppend, chunkLevel, parent, chunkWG, jobC, quitC, false, rootKey) + parent = NewTreeEntry(self) + } + + } + + workers := self.getWorkerCount() + if int64(len(jobC)) > workers && workers < ChunkProcessors { + if processorWG != nil { + processorWG.Add(1) + } + self.incrementWorkerCount() + go self.processor(self.workerCount, jobC, chunkC, errC, quitC, storageWG, processorWG) + } + + } + +} + +func (self *PyramidChunker) buildTree(isAppend bool, chunkLevel [][]*TreeEntry, ent *TreeEntry, chunkWG *sync.WaitGroup, jobC chan *chunkJob, quitC chan bool, last bool, rootKey []byte) { + chunkWG.Wait() + self.enqueueTreeChunk(chunkLevel, ent, chunkWG, jobC, quitC, last) + + compress := false + endLvl := self.branches + for lvl := int64(0); lvl < self.branches; lvl++ { + lvlCount := int64(len(chunkLevel[lvl])) + if lvlCount >= self.branches { + endLvl = lvl + 1 + compress = true + break + } + } + + if compress == false && last == false { + return + } + + // Wait for all the keys to be processed before compressing the tree + chunkWG.Wait() + + for lvl := int64(ent.level); lvl < endLvl; lvl++ { + + lvlCount := int64(len(chunkLevel[lvl])) + if lvlCount == 1 && last == true { + copy(rootKey, chunkLevel[lvl][0].key) + return + } + + for startCount := int64(0); startCount < lvlCount; startCount += self.branches { + + endCount := startCount + self.branches + if endCount > lvlCount { + endCount = lvlCount + } + + var nextLvlCount int64 + var tempEntry *TreeEntry + if len(chunkLevel[lvl+1]) > 0 { + nextLvlCount = int64(len(chunkLevel[lvl+1]) - 1) + tempEntry = chunkLevel[lvl+1][nextLvlCount] + } + if isAppend == true && tempEntry != nil && tempEntry.updatePending == true { + updateEntry := &TreeEntry{ + level: int(lvl + 1), + branchCount: 0, + subtreeSize: 0, + chunk: make([]byte, self.chunkSize+8), + key: make([]byte, self.hashSize), + index: int(nextLvlCount), + updatePending: true, + } + for index := int64(0); index < lvlCount; index++ { + updateEntry.branchCount++ + updateEntry.subtreeSize += chunkLevel[lvl][index].subtreeSize + copy(updateEntry.chunk[8+(index*self.hashSize):8+((index+1)*self.hashSize)], chunkLevel[lvl][index].key[:self.hashSize]) + } + + self.enqueueTreeChunk(chunkLevel, updateEntry, chunkWG, jobC, quitC, last) + + } else { + + noOfBranches := endCount - startCount + newEntry := &TreeEntry{ + level: int(lvl + 1), + branchCount: noOfBranches, + subtreeSize: 0, + chunk: make([]byte, (noOfBranches*self.hashSize)+8), + key: make([]byte, self.hashSize), + index: int(nextLvlCount), + updatePending: false, + } + + index := int64(0) + for i := startCount; i < endCount; i++ { + entry := chunkLevel[lvl][i] + newEntry.subtreeSize += entry.subtreeSize + copy(newEntry.chunk[8+(index*self.hashSize):8+((index+1)*self.hashSize)], entry.key[:self.hashSize]) + index++ + } + + self.enqueueTreeChunk(chunkLevel, newEntry, chunkWG, jobC, quitC, last) + + } + + } + + if isAppend == false { + chunkWG.Wait() + if compress == true { + chunkLevel[lvl] = nil + } + } } + } + +func (self *PyramidChunker) enqueueTreeChunk(chunkLevel [][]*TreeEntry, ent *TreeEntry, chunkWG *sync.WaitGroup, jobC chan *chunkJob, quitC chan bool, last bool) { + if ent != nil { + + // wait for data chunks to get over before processing the tree chunk + if last == true { + chunkWG.Wait() + } + + binary.LittleEndian.PutUint64(ent.chunk[:8], ent.subtreeSize) + ent.key = make([]byte, self.hashSize) + chunkWG.Add(1) + select { + case jobC <- &chunkJob{ent.key, ent.chunk[:ent.branchCount*self.hashSize+8], int64(ent.subtreeSize), chunkWG, TreeChunk, 0}: + case <-quitC: + } + + // Update or append based on weather it is a new entry or being reused + if ent.updatePending == true { + chunkWG.Wait() + chunkLevel[ent.level][ent.index] = ent + } else { + chunkLevel[ent.level] = append(chunkLevel[ent.level], ent) + } + + } +} + +func (self *PyramidChunker) enqueueDataChunk(chunkData []byte, size uint64, parent *TreeEntry, chunkWG *sync.WaitGroup, jobC chan *chunkJob, quitC chan bool) Key { + binary.LittleEndian.PutUint64(chunkData[:8], size) + pkey := parent.chunk[8+parent.branchCount*self.hashSize : 8+(parent.branchCount+1)*self.hashSize] + + chunkWG.Add(1) + select { + case jobC <- &chunkJob{pkey, chunkData[:size+8], int64(size), chunkWG, DataChunk, -1}: + case <-quitC: + } + + return pkey + +}
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