mirror of
https://github.com/restic/restic.git
synced 2024-09-05 19:09:24 +02:00
The set covers necessary, existing and duplicate blobs. This removes the duplicate sets used to track whether all necessary blobs also exist. This reduces the memory usage of prune by about 20-30%.
141 lines
3.7 KiB
Go
141 lines
3.7 KiB
Go
package repository
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import (
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"context"
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"sync"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/restic"
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"github.com/restic/restic/internal/ui/progress"
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"golang.org/x/sync/errgroup"
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)
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type repackBlobSet interface {
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Has(bh restic.BlobHandle) bool
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Delete(bh restic.BlobHandle)
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Len() int
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}
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// Repack takes a list of packs together with a list of blobs contained in
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// these packs. Each pack is loaded and the blobs listed in keepBlobs is saved
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// into a new pack. Returned is the list of obsolete packs which can then
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// be removed.
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//
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// The map keepBlobs is modified by Repack, it is used to keep track of which
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// blobs have been processed.
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func Repack(ctx context.Context, repo restic.Repository, dstRepo restic.Repository, packs restic.IDSet, keepBlobs repackBlobSet, p *progress.Counter) (obsoletePacks restic.IDSet, err error) {
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debug.Log("repacking %d packs while keeping %d blobs", len(packs), keepBlobs.Len())
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if repo == dstRepo && dstRepo.Connections() < 2 {
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return nil, errors.Fatal("repack step requires a backend connection limit of at least two")
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}
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wg, wgCtx := errgroup.WithContext(ctx)
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dstRepo.StartPackUploader(wgCtx, wg)
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wg.Go(func() error {
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var err error
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obsoletePacks, err = repack(wgCtx, repo, dstRepo, packs, keepBlobs, p)
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return err
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})
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if err := wg.Wait(); err != nil {
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return nil, err
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}
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return obsoletePacks, nil
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}
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func repack(ctx context.Context, repo restic.Repository, dstRepo restic.Repository, packs restic.IDSet, keepBlobs repackBlobSet, p *progress.Counter) (obsoletePacks restic.IDSet, err error) {
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wg, wgCtx := errgroup.WithContext(ctx)
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var keepMutex sync.Mutex
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downloadQueue := make(chan restic.PackBlobs)
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wg.Go(func() error {
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defer close(downloadQueue)
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for pbs := range repo.Index().ListPacks(wgCtx, packs) {
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var packBlobs []restic.Blob
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keepMutex.Lock()
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// filter out unnecessary blobs
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for _, entry := range pbs.Blobs {
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h := restic.BlobHandle{ID: entry.ID, Type: entry.Type}
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if keepBlobs.Has(h) {
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packBlobs = append(packBlobs, entry)
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}
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}
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keepMutex.Unlock()
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select {
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case downloadQueue <- restic.PackBlobs{PackID: pbs.PackID, Blobs: packBlobs}:
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case <-wgCtx.Done():
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return wgCtx.Err()
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}
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}
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return nil
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})
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worker := func() error {
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for t := range downloadQueue {
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err := StreamPack(wgCtx, repo.Backend().Load, repo.Key(), t.PackID, t.Blobs, func(blob restic.BlobHandle, buf []byte, err error) error {
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if err != nil {
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var ierr error
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// check whether we can get a valid copy somewhere else
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buf, ierr = repo.LoadBlob(wgCtx, blob.Type, blob.ID, nil)
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if ierr != nil {
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// no luck, return the original error
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return err
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}
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}
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keepMutex.Lock()
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// recheck whether some other worker was faster
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shouldKeep := keepBlobs.Has(blob)
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if shouldKeep {
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keepBlobs.Delete(blob)
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}
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keepMutex.Unlock()
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if !shouldKeep {
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return nil
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}
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// We do want to save already saved blobs!
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_, _, _, err = dstRepo.SaveBlob(wgCtx, blob.Type, buf, blob.ID, true)
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if err != nil {
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return err
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}
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debug.Log(" saved blob %v", blob.ID)
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return nil
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})
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if err != nil {
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return err
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}
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p.Add(1)
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}
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return nil
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}
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// as packs are streamed the concurrency is limited by IO
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// reduce by one to ensure that uploading is always possible
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repackWorkerCount := int(repo.Connections() - 1)
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if repo != dstRepo {
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// no need to share the upload and download connections for different repositories
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repackWorkerCount = int(repo.Connections())
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}
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for i := 0; i < repackWorkerCount; i++ {
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wg.Go(worker)
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}
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if err := wg.Wait(); err != nil {
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return nil, err
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}
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if err := dstRepo.Flush(ctx); err != nil {
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return nil, err
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}
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return packs, nil
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}
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