mirror of
https://github.com/chrislusf/seaweedfs
synced 2024-09-05 08:30:35 +02:00
216 lines
7 KiB
Go
216 lines
7 KiB
Go
package storage
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import (
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"fmt"
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"io"
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"io/ioutil"
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"net/url"
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"os"
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"sort"
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"strconv"
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"github.com/chrislusf/seaweedfs/weed/glog"
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"github.com/chrislusf/seaweedfs/weed/operation"
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"github.com/chrislusf/seaweedfs/weed/storage/needle"
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. "github.com/chrislusf/seaweedfs/weed/storage/types"
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"github.com/chrislusf/seaweedfs/weed/util"
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)
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// The volume sync with a master volume via 2 steps:
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// 1. The slave checks master side to find subscription checkpoint
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// to setup the replication.
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// 2. The slave receives the updates from master
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/*
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Assume the slave volume needs to follow the master volume.
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The master volume could be compacted, and could be many files ahead of
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slave volume.
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Step 1:
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The slave volume will ask the master volume for a snapshot
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of (existing file entries, last offset, number of compacted times).
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For each entry x in master existing file entries:
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if x does not exist locally:
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add x locally
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For each entry y in local slave existing file entries:
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if y does not exist on master:
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delete y locally
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Step 2:
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After this, use the last offset and number of compacted times to request
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the master volume to send a new file, and keep looping. If the number of
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compacted times is changed, go back to step 1 (very likely this can be
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optimized more later).
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*/
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func (v *Volume) Synchronize(volumeServer string) (err error) {
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var lastCompactRevision uint16 = 0
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var compactRevision uint16 = 0
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var masterMap *needle.CompactMap
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for i := 0; i < 3; i++ {
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if masterMap, _, compactRevision, err = fetchVolumeFileEntries(volumeServer, v.Id); err != nil {
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return fmt.Errorf("Failed to sync volume %d entries with %s: %v", v.Id, volumeServer, err)
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}
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if lastCompactRevision != compactRevision && lastCompactRevision != 0 {
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if err = v.Compact(0); err != nil {
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return fmt.Errorf("Compact Volume before synchronizing %v", err)
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}
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if err = v.commitCompact(); err != nil {
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return fmt.Errorf("Commit Compact before synchronizing %v", err)
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}
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}
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lastCompactRevision = compactRevision
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if err = v.trySynchronizing(volumeServer, masterMap, compactRevision); err == nil {
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return
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}
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}
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return
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}
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type ByOffset []needle.NeedleValue
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func (a ByOffset) Len() int { return len(a) }
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func (a ByOffset) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
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func (a ByOffset) Less(i, j int) bool { return a[i].Offset < a[j].Offset }
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// trySynchronizing sync with remote volume server incrementally by
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// make up the local and remote delta.
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func (v *Volume) trySynchronizing(volumeServer string, masterMap *needle.CompactMap, compactRevision uint16) error {
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slaveIdxFile, err := os.Open(v.nm.IndexFileName())
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if err != nil {
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return fmt.Errorf("Open volume %d index file: %v", v.Id, err)
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}
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defer slaveIdxFile.Close()
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slaveMap, err := LoadBtreeNeedleMap(slaveIdxFile)
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if err != nil {
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return fmt.Errorf("Load volume %d index file: %v", v.Id, err)
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}
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var delta []needle.NeedleValue
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if err := masterMap.Visit(func(needleValue needle.NeedleValue) error {
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if needleValue.Key == NeedleIdEmpty {
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return nil
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}
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if _, ok := slaveMap.Get(needleValue.Key); ok {
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return nil // skip intersection
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}
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delta = append(delta, needleValue)
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return nil
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}); err != nil {
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return fmt.Errorf("Add master entry: %v", err)
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}
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if err := slaveMap.m.Visit(func(needleValue needle.NeedleValue) error {
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if needleValue.Key == NeedleIdEmpty {
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return nil
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}
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if _, ok := masterMap.Get(needleValue.Key); ok {
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return nil // skip intersection
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}
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needleValue.Size = 0
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delta = append(delta, needleValue)
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return nil
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}); err != nil {
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return fmt.Errorf("Remove local entry: %v", err)
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}
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// simulate to same ordering of remote .dat file needle entries
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sort.Sort(ByOffset(delta))
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// make up the delta
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fetchCount := 0
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volumeDataContentHandlerUrl := "http://" + volumeServer + "/admin/sync/data"
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for _, needleValue := range delta {
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if needleValue.Size == 0 {
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// remove file entry from local
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v.removeNeedle(needleValue.Key)
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continue
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}
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// add master file entry to local data file
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if err := v.fetchNeedle(volumeDataContentHandlerUrl, needleValue, compactRevision); err != nil {
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glog.V(0).Infof("Fetch needle %v from %s: %v", needleValue, volumeServer, err)
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return err
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}
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fetchCount++
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}
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glog.V(1).Infof("Fetched %d needles from %s", fetchCount, volumeServer)
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return nil
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}
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func fetchVolumeFileEntries(volumeServer string, vid VolumeId) (m *needle.CompactMap, lastOffset uint64, compactRevision uint16, err error) {
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m = needle.NewCompactMap()
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syncStatus, err := operation.GetVolumeSyncStatus(volumeServer, vid.String())
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if err != nil {
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return m, 0, 0, err
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}
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total := 0
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err = operation.GetVolumeIdxEntries(volumeServer, vid.String(), func(key NeedleId, offset Offset, size uint32) {
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// println("remote key", key, "offset", offset*NeedlePaddingSize, "size", size)
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if offset > 0 && size != TombstoneFileSize {
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m.Set(NeedleId(key), offset, size)
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} else {
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m.Delete(NeedleId(key))
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}
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total++
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})
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glog.V(2).Infof("server %s volume %d, entries %d, last offset %d, revision %d", volumeServer, vid, total, syncStatus.TailOffset, syncStatus.CompactRevision)
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return m, syncStatus.TailOffset, syncStatus.CompactRevision, err
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}
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func (v *Volume) GetVolumeSyncStatus() operation.SyncVolumeResponse {
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var syncStatus = operation.SyncVolumeResponse{}
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if stat, err := v.dataFile.Stat(); err == nil {
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syncStatus.TailOffset = uint64(stat.Size())
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}
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syncStatus.IdxFileSize = v.nm.IndexFileSize()
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syncStatus.CompactRevision = v.SuperBlock.CompactRevision
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syncStatus.Ttl = v.SuperBlock.Ttl.String()
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syncStatus.Replication = v.SuperBlock.ReplicaPlacement.String()
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return syncStatus
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}
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func (v *Volume) IndexFileContent() ([]byte, error) {
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return v.nm.IndexFileContent()
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}
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// removeNeedle removes one needle by needle key
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func (v *Volume) removeNeedle(key NeedleId) {
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n := new(Needle)
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n.Id = key
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v.deleteNeedle(n)
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}
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// fetchNeedle fetches a remote volume needle by vid, id, offset
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// The compact revision is checked first in case the remote volume
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// is compacted and the offset is invalid any more.
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func (v *Volume) fetchNeedle(volumeDataContentHandlerUrl string,
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needleValue needle.NeedleValue, compactRevision uint16) error {
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// add master file entry to local data file
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values := make(url.Values)
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values.Add("revision", strconv.Itoa(int(compactRevision)))
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values.Add("volume", v.Id.String())
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values.Add("id", needleValue.Key.String())
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values.Add("offset", strconv.FormatUint(uint64(needleValue.Offset), 10))
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values.Add("size", strconv.FormatUint(uint64(needleValue.Size), 10))
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glog.V(4).Infof("Fetch %+v", needleValue)
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return util.GetUrlStream(volumeDataContentHandlerUrl, values, func(r io.Reader) error {
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b, err := ioutil.ReadAll(r)
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if err != nil {
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return fmt.Errorf("Reading from %s error: %v", volumeDataContentHandlerUrl, err)
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}
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offset, err := v.AppendBlob(b)
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if err != nil {
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return fmt.Errorf("Appending volume %d error: %v", v.Id, err)
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}
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// println("add key", needleValue.Key, "offset", offset, "size", needleValue.Size)
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v.nm.Put(needleValue.Key, Offset(offset/NeedlePaddingSize), needleValue.Size)
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return nil
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})
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}
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