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rework tracking logic; do it lazily and far more efficiently

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This commit is contained in:
vyzo 2021-07-03 16:10:37 +03:00
parent 9d6cabd18a
commit 228a435ba7
2 changed files with 169 additions and 149 deletions
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2
blockstore/splitstore/markset.go
View File

@ -65,7 +65,7 @@ func NewMapMarkSetEnv(ts bool) (*MapMarkSetEnv, error) {
func (e *MapMarkSetEnv) Create(name string, sizeHint int64) (MarkSet, error) {
return &MapMarkSet{
set: make(map[string]struct{}),
set: make(map[string]struct{}, sizeHint),
ts: e.ts,
}, nil
}

302
blockstore/splitstore/splitstore.go
View File

@ -79,6 +79,8 @@ var (
// used to signal end of walk
errStopWalk = errors.New("stop walk")
// used to signal a missing object when protecting recursive references
errMissingObject = errors.New("missing object")
// set this to true if you are debugging the splitstore to enable debug logging
enableDebugLog = false
@ -146,8 +148,7 @@ type SplitStore struct {
cold bstore.Blockstore
tracker TrackingStore
env MarkSetEnv
markSetEnv MarkSetEnv
markSetSize int64
ctx context.Context
@ -159,9 +160,10 @@ type SplitStore struct {
txnLk sync.RWMutex
txnEnv MarkSetEnv
txnProtect MarkSet
txnMarkSet MarkSet
// pending write set
pendingWrites map[cid.Cid]bool
pendingWrites map[cid.Cid]struct{}
}
var _ bstore.Blockstore = (*SplitStore)(nil)
@ -177,7 +179,7 @@ func Open(path string, ds dstore.Datastore, hot, cold bstore.Blockstore, cfg *Co
}
// the markset env
env, err := OpenMarkSetEnv(path, cfg.MarkSetType)
markSetEnv, err := OpenMarkSetEnv(path, "mapts")
if err != nil {
_ = tracker.Close()
return nil, err
@ -187,7 +189,7 @@ func Open(path string, ds dstore.Datastore, hot, cold bstore.Blockstore, cfg *Co
txnEnv, err := OpenMarkSetEnv(path, "mapts")
if err != nil {
_ = tracker.Close()
_ = env.Close()
_ = markSetEnv.Close()
return nil, err
}
@ -198,12 +200,12 @@ func Open(path string, ds dstore.Datastore, hot, cold bstore.Blockstore, cfg *Co
hot: hot,
cold: cold,
tracker: tracker,
env: env,
markSetEnv: markSetEnv,
txnEnv: txnEnv,
coldPurgeSize: defaultColdPurgeSize,
pendingWrites: make(map[cid.Cid]bool),
pendingWrites: make(map[cid.Cid]struct{}),
}
ss.ctx, ss.cancel = context.WithCancel(context.Background())
@ -246,7 +248,7 @@ func (s *SplitStore) Has(c cid.Cid) (bool, error) {
// that this is an implicit Write.
vmCtx := s.isVMCopyContext()
if vmCtx {
s.trackWrite(c, true)
s.trackWrite(c)
}
// also make sure the object is considered live during compaction in case we have already
@ -254,11 +256,14 @@ func (s *SplitStore) Has(c cid.Cid) (bool, error) {
// when within vm copy context, dags will be recursively referenced.
// in case of a race with purge, this will return a track error, which we can use to
// signal to the vm that the object is not fully present.
trackErr := s.trackTxnRef(c, vmCtx)
err = s.trackTxnRef(c, vmCtx)
if xerrors.Is(err, errMissingObject) {
// we failed to recursively protect the object because some inner object has been purged;
// signal to the VM to copy.
return false, nil
}
// if we failed to track the object and all its dependencies, then return false so as
// to cause the vm to copy
return trackErr == nil, nil
return true, err
}
return s.cold.Has(c)
@ -333,7 +338,7 @@ func (s *SplitStore) Put(blk blocks.Block) error {
err := s.hot.Put(blk)
if err == nil {
s.trackWrite(blk.Cid(), false)
s.trackWrite(blk.Cid())
err = s.trackTxnRef(blk.Cid(), false)
}
@ -509,7 +514,7 @@ func (s *SplitStore) Close() error {
s.flushPendingWrites(false)
s.cancel()
return multierr.Combine(s.tracker.Close(), s.env.Close(), s.debug.Close())
return multierr.Combine(s.tracker.Close(), s.markSetEnv.Close(), s.debug.Close())
}
func (s *SplitStore) HeadChange(_, apply []*types.TipSet) error {
@ -584,11 +589,11 @@ func (s *SplitStore) updateWriteEpoch() {
// Unfortunately we can't just directly tracker.Put one by one, as it is ridiculously slow with
// bbolt because of syncing (order of 10ms), so we batch them.
func (s *SplitStore) trackWrite(c cid.Cid, implicit bool) {
func (s *SplitStore) trackWrite(c cid.Cid) {
s.mx.Lock()
defer s.mx.Unlock()
s.pendingWrites[c] = implicit
s.pendingWrites[c] = struct{}{}
}
// and also combine batch writes into them
@ -597,7 +602,7 @@ func (s *SplitStore) trackWriteMany(cids []cid.Cid) {
defer s.mx.Unlock()
for _, c := range cids {
s.pendingWrites[c] = false
s.pendingWrites[c] = struct{}{}
}
}
@ -612,52 +617,10 @@ func (s *SplitStore) flushPendingWrites(locked bool) {
}
cids := make([]cid.Cid, 0, len(s.pendingWrites))
seen := make(map[cid.Cid]struct{})
walked := cid.NewSet()
for c, implicit := range s.pendingWrites {
_, ok := seen[c]
if ok {
continue
}
for c := range s.pendingWrites {
cids = append(cids, c)
seen[c] = struct{}{}
if !implicit {
continue
}
// recursively walk dags to propagate dependent references
if c.Prefix().Codec != cid.DagCBOR {
continue
}
err := s.walkLinks(c, walked, func(c cid.Cid) error {
_, ok := seen[c]
if !ok {
cids = append(cids, c)
seen[c] = struct{}{}
}
// if it is a block reference, short-circuit or else we'll end up walking the entire chain
isBlock, err := s.isBlockHeader(c)
if err != nil {
return xerrors.Errorf("error determining if cid %s is a block header: %w", c, err)
}
if isBlock {
return errStopWalk
}
return nil
})
if err != nil {
log.Warnf("error tracking dependent writes for cid %s: %s", c, err)
}
}
s.pendingWrites = make(map[cid.Cid]bool)
s.pendingWrites = make(map[cid.Cid]struct{})
epoch := s.writeEpoch
err := s.tracker.PutBatch(cids, epoch)
@ -687,55 +650,52 @@ func (s *SplitStore) isBlockHeader(c cid.Cid) (isBlock bool, err error) {
return isBlock, err
}
func (s *SplitStore) trackTxnRef(c cid.Cid, implicit bool) error {
func (s *SplitStore) trackTxnRef(c cid.Cid, recursive bool) error {
if s.txnProtect == nil {
// not compacting
return nil
}
// NOTE: this occurs check assumes a markset without false positives, which is currently the case
// with the map
has, err := s.txnProtect.Has(c)
if !recursive {
return s.txnProtect.Mark(c)
}
// it's a recursive reference in vm context, protect links if they are not in the markset already
return s.walkLinks(c, cid.NewSet(), func(c cid.Cid) error {
mark, err := s.txnMarkSet.Has(c)
if err != nil {
log.Errorf("error occur checking object (cid: %s) for compaction transaction: %s", c, err)
return err
return xerrors.Errorf("error checking mark set for %s: %w", c, err)
}
if has {
return nil
}
if c.Prefix().Codec != cid.DagCBOR || !implicit {
err = s.txnProtect.Mark(c)
} else {
err = s.walkLinks(c, cid.NewSet(), func(c cid.Cid) error {
// check if it is a block; implicitly checks if the object exists --if it doesn't because
// it has been purged, it will be an error
isBlock, err := s.isBlockHeader(c)
if err != nil {
return xerrors.Errorf("error determining if cid %s is a block header: %w", c, err)
}
// mark the object
err = s.txnProtect.Mark(c)
if err != nil {
return err
}
// if it is a block reference, short-circuit or else we'll end up walking the entire chain
if isBlock {
// it's marked, nothing to do
if mark {
return errStopWalk
}
return nil
})
}
live, err := s.txnProtect.Has(c)
if err != nil {
log.Warnf("error protecting object (cid: %s) from compaction transaction: %s", c, err)
return xerrors.Errorf("error checking portected set for %s: %w", c, err)
}
return err
if live {
return errStopWalk
}
// this occurs check is necessary because cold objects are purged in arbitrary order
has, err := s.hot.Has(c)
if err != nil {
return xerrors.Errorf("error checking hotstore for %s: %w", c, err)
}
// it has been deleted, signal to the vm to copy
if !has {
log.Warnf("missing object for recursive reference to %s: %s", c, err)
return errMissingObject
}
// mark it
return s.txnProtect.Mark(c)
})
}
func (s *SplitStore) trackTxnRefMany(cids []cid.Cid) error {
@ -998,38 +958,32 @@ func (s *SplitStore) doCompact(curTs *types.TipSet) error {
log.Infow("running compaction", "currentEpoch", currentEpoch, "baseEpoch", s.baseEpoch, "coldEpoch", coldEpoch, "boundaryEpoch", boundaryEpoch)
markSet, err := s.env.Create("live", s.markSetSize)
markSet, err := s.markSetEnv.Create("live", s.markSetSize)
if err != nil {
return xerrors.Errorf("error creating mark set: %w", err)
}
defer markSet.Close() //nolint:errcheck
defer s.debug.Flush()
// create the transaction protect filter
s.txnLk.Lock()
s.txnProtect, err = s.txnEnv.Create("protected", s.markSetSize)
if err != nil {
s.txnLk.Unlock()
return xerrors.Errorf("error creating transactional mark set: %w", err)
}
s.txnLk.Unlock()
defer func() {
s.txnLk.Lock()
_ = s.txnProtect.Close()
s.txnProtect = nil
s.txnLk.Unlock()
}()
// 1. mark reachable objects by walking the chain from the current epoch to the boundary epoch
log.Infow("marking reachable blocks", "currentEpoch", currentEpoch, "boundaryEpoch", boundaryEpoch)
startMark := time.Now()
var count int64
err = s.walk(curTs, boundaryEpoch, true, s.cfg.HotHeaders,
func(cid cid.Cid) error {
func(c cid.Cid) error {
mark, err := markSet.Has(c)
if err != nil {
return xerrors.Errorf("error checking mark set for %s: %w", c, err)
}
if mark {
// already marked, don't recurse its links
return errStopWalk
}
count++
return markSet.Mark(cid)
return markSet.Mark(c)
})
if err != nil {
@ -1042,34 +996,45 @@ func (s *SplitStore) doCompact(curTs *types.TipSet) error {
log.Infow("marking done", "took", time.Since(startMark), "marked", count)
// create the transaction protect filter
s.txnLk.Lock()
s.txnProtect, err = s.txnEnv.Create("protected", s.markSetSize)
if err != nil {
s.txnLk.Unlock()
return xerrors.Errorf("error creating transactional mark set: %w", err)
}
s.txnMarkSet = markSet
s.txnLk.Unlock()
defer func() {
s.txnLk.Lock()
_ = s.txnProtect.Close()
s.txnProtect = nil
s.txnMarkSet = nil
s.txnLk.Unlock()
}()
// flush pending writes to update the tracker
log.Info("flushing pending writes")
startFlush := time.Now()
s.flushPendingWrites(false)
log.Infow("flushing done", "took", time.Since(startFlush))
// 2. move cold unreachable objects to the coldstore
log.Info("collecting cold objects")
log.Info("collecting candidate cold objects")
startCollect := time.Now()
cold := make([]cid.Cid, 0, s.coldPurgeSize)
candidates := make(map[cid.Cid]struct{}, s.coldPurgeSize)
towalk := make([]cid.Cid, 0, count)
// some stats for logging
var hotCnt, coldCnt, liveCnt int
// 2.1 iterate through the tracking store and collect unreachable cold objects
err = s.tracker.ForEach(func(cid cid.Cid, writeEpoch abi.ChainEpoch) error {
// is the object still hot?
if writeEpoch > coldEpoch {
// yes, stay in the hotstore
hotCnt++
return nil
}
// check whether it is reachable in the cold boundary
mark, err := markSet.Has(cid)
// for every hot object that is a dag and not in the markset, walk for links and
// and mark reachable objects
err = s.tracker.ForEach(func(c cid.Cid, writeEpoch abi.ChainEpoch) error {
// was it marked?
mark, err := markSet.Has(c)
if err != nil {
return xerrors.Errorf("error checkiing mark set for %s: %w", cid, err)
return xerrors.Errorf("error checkiing mark set for %s: %w", c, err)
}
if mark {
@ -1077,37 +1042,92 @@ func (s *SplitStore) doCompact(curTs *types.TipSet) error {
return nil
}
live, err := s.txnProtect.Has(cid)
if err != nil {
return xerrors.Errorf("error checking liveness for %s: %w", cid, err)
}
// is the object still hot?
if writeEpoch > coldEpoch {
// yes, stay in the hotstore
hotCnt++
if live {
liveCnt++
// if it is a DAG, add it to the walk list to recursively update the markset
if c.Prefix().Codec != cid.DagCBOR {
return nil
}
// it's cold, mark it for move
cold = append(cold, cid)
towalk = append(towalk, c)
return nil
}
// it's cold, mark it as candidate for move
candidates[c] = struct{}{}
coldCnt++
return nil
})
if err != nil {
return xerrors.Errorf("error collecting cold objects: %w", err)
return xerrors.Errorf("error collecting candidate cold objects: %w", err)
}
log.Infow("candidate collection done", "took", time.Since(startCollect))
if coldCnt > 0 {
s.coldPurgeSize = coldCnt + coldCnt>>2 // overestimate a bit
}
log.Infow("collection done", "took", time.Since(startCollect))
// walk hot dags that were not marked and recursively update the mark set
log.Info("updating mark set for hot dags")
startMark = time.Now()
walked := cid.NewSet()
for _, c := range towalk {
err = s.walkLinks(c, walked, func(c cid.Cid) error {
mark, err := markSet.Has(c)
if err != nil {
return xerrors.Errorf("error checking mark set for %s: %w", c, err)
}
if mark {
// already marked, don't recurse its links
return errStopWalk
}
liveCnt++
return markSet.Mark(c)
})
if err != nil {
return xerrors.Errorf("error walking %s: %w", c, err)
}
}
log.Infow("updating mark set done", "took", time.Since(startMark))
// filter the candidate set for objects newly marked as hot
if liveCnt > 0 {
for c := range candidates {
mark, err := markSet.Has(c)
if err != nil {
return xerrors.Errorf("error checking mark set for %s: %w", c, err)
}
if mark {
delete(candidates, c)
}
}
}
// create the cold object list
coldCnt -= liveCnt
cold := make([]cid.Cid, 0, coldCnt)
for c := range candidates {
cold = append(cold, c)
}
log.Infow("compaction stats", "hot", hotCnt, "cold", coldCnt, "live", liveCnt)
stats.Record(context.Background(), metrics.SplitstoreCompactionHot.M(int64(hotCnt)))
stats.Record(context.Background(), metrics.SplitstoreCompactionCold.M(int64(coldCnt)))
// Enter critical section
log.Info("entering critical section")
atomic.StoreInt32(&s.critsection, 1)
defer atomic.StoreInt32(&s.critsection, 0)