func (db *DB) compactionError() {
var (
err error
wlocked bool
)
noerr:
// No error.
for {
select {
case err = <-db.compErrSetC:
switch {
case err == nil:
case errors.IsCorrupted(err):
goto hasperr
default:
goto haserr
}
case _, _ = <-db.closeC:
return
}
}
haserr:
// Transient error.
for {
select {
case db.compErrC <- err:
case err = <-db.compErrSetC:
switch {
case err == nil:
goto noerr
case errors.IsCorrupted(err):
goto hasperr
default:
}
case _, _ = <-db.closeC:
return
}
}
hasperr:
// Persistent error.
for {
select {
case db.compErrC <- err:
case db.compPerErrC <- err:
case db.writeLockC <- struct{}{}:
// Hold write lock, so that write won't pass-through.
wlocked = true
case _, _ = <-db.closeC:
if wlocked {
// We should release the lock or Close will hang.
<-db.writeLockC
}
return
}
}
}
func (i *indexedIterator) dataErr() bool {
if err := i.data.Error(); err != nil {
if i.errf != nil {
i.errf(err)
}
if i.strict || !errors.IsCorrupted(err) {
i.err = err
return true
}
}
return false
}
func (i *mergedIterator) iterErr(iter Iterator) bool {
if err := iter.Error(); err != nil {
if i.errf != nil {
i.errf(err)
}
if i.strict || !errors.IsCorrupted(err) {
i.err = err
return true
}
}
return false
}
// NewReader creates a new initialized table reader for the file.
// The fi, cache and bpool is optional and can be nil.
//
// The returned table reader instance is goroutine-safe.
func NewReader(f io.ReaderAt, size int64, fi *storage.FileInfo, cache *cache.CacheGetter, bpool *util.BufferPool, o *opt.Options) (*Reader, error) {
if f == nil {
return nil, errors.New("leveldb/table: nil file")
}
r := &Reader{
fi: fi,
reader: f,
cache: cache,
bpool: bpool,
o: o,
cmp: o.GetComparer(),
verifyChecksum: o.GetStrict(opt.StrictBlockChecksum),
}
if size < footerLen {
r.err = r.newErrCorrupted(0, size, "table", "too small")
return r, nil
}
footerPos := size - footerLen
var footer [footerLen]byte
if _, err := r.reader.ReadAt(footer[:], footerPos); err != nil && err != io.EOF {
return nil, err
}
if string(footer[footerLen-len(magic):footerLen]) != magic {
r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad magic number")
return r, nil
}
var n int
// Decode the metaindex block handle.
r.metaBH, n = decodeBlockHandle(footer[:])
if n == 0 {
r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad metaindex block handle")
return r, nil
}
// Decode the index block handle.
r.indexBH, n = decodeBlockHandle(footer[n:])
if n == 0 {
r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad index block handle")
return r, nil
}
// Read metaindex block.
metaBlock, err := r.readBlock(r.metaBH, true)
if err != nil {
if errors.IsCorrupted(err) {
r.err = err
return r, nil
} else {
return nil, err
}
}
// Set data end.
r.dataEnd = int64(r.metaBH.offset)
// Read metaindex.
metaIter := r.newBlockIter(metaBlock, nil, nil, true)
for metaIter.Next() {
key := string(metaIter.Key())
if !strings.HasPrefix(key, "filter.") {
continue
}
fn := key[7:]
if f0 := o.GetFilter(); f0 != nil && f0.Name() == fn {
r.filter = f0
} else {
for _, f0 := range o.GetAltFilters() {
if f0.Name() == fn {
r.filter = f0
break
}
}
}
if r.filter != nil {
filterBH, n := decodeBlockHandle(metaIter.Value())
if n == 0 {
continue
}
r.filterBH = filterBH
// Update data end.
r.dataEnd = int64(filterBH.offset)
break
}
}
metaIter.Release()
metaBlock.Release()
// Cache index and filter block locally, since we don't have global cache.
if cache == nil {
r.indexBlock, err = r.readBlock(r.indexBH, true)
if err != nil {
if errors.IsCorrupted(err) {
r.err = err
return r, nil
} else {
return nil, err
}
}
if r.filter != nil {
r.filterBlock, err = r.readFilterBlock(r.filterBH)
if err != nil {
if !errors.IsCorrupted(err) {
return nil, err
}
// Don't use filter then.
r.filter = nil
}
}
}
return r, nil
}
func (r *Reader) find(key []byte, filtered bool, ro *opt.ReadOptions, noValue bool) (rkey, value []byte, err error) {
r.mu.RLock()
defer r.mu.RUnlock()
if r.err != nil {
err = r.err
return
}
indexBlock, rel, err := r.getIndexBlock(true)
if err != nil {
return
}
defer rel.Release()
index := r.newBlockIter(indexBlock, nil, nil, true)
defer index.Release()
if !index.Seek(key) {
err = index.Error()
if err == nil {
err = ErrNotFound
}
return
}
dataBH, n := decodeBlockHandle(index.Value())
if n == 0 {
r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
return
}
if filtered && r.filter != nil {
filterBlock, frel, ferr := r.getFilterBlock(true)
if ferr == nil {
if !filterBlock.contains(r.filter, dataBH.offset, key) {
frel.Release()
return nil, nil, ErrNotFound
}
frel.Release()
} else if !errors.IsCorrupted(ferr) {
err = ferr
return
}
}
data := r.getDataIter(dataBH, nil, r.verifyChecksum, !ro.GetDontFillCache())
defer data.Release()
if !data.Seek(key) {
err = data.Error()
if err == nil {
err = ErrNotFound
}
return
}
// Don't use block buffer, no need to copy the buffer.
rkey = data.Key()
if !noValue {
if r.bpool == nil {
value = data.Value()
} else {
// Use block buffer, and since the buffer will be recycled, the buffer
// need to be copied.
value = append([]byte{}, data.Value()...)
}
}
return
}
// Recover a database session; need external synchronization.
func (s *session) recover() (err error) {
defer func() {
if os.IsNotExist(err) {
// Don't return os.ErrNotExist if the underlying storage contains
// other files that belong to LevelDB. So the DB won't get trashed.
if files, _ := s.stor.GetFiles(storage.TypeAll); len(files) > 0 {
err = &errors.ErrCorrupted{File: &storage.FileInfo{Type: storage.TypeManifest}, Err: &errors.ErrMissingFiles{}}
}
}
}()
m, err := s.stor.GetManifest()
if err != nil {
return
}
reader, err := m.Open()
if err != nil {
return
}
defer reader.Close()
strict := s.o.GetStrict(opt.StrictManifest)
jr := journal.NewReader(reader, dropper{s, m}, strict, true)
staging := s.stVersion.newStaging()
rec := &sessionRecord{numLevel: s.o.GetNumLevel()}
for {
var r io.Reader
r, err = jr.Next()
if err != nil {
if err == io.EOF {
err = nil
break
}
return errors.SetFile(err, m)
}
err = rec.decode(r)
if err == nil {
// save compact pointers
for _, r := range rec.compPtrs {
s.stCompPtrs[r.level] = iKey(r.ikey)
}
// commit record to version staging
staging.commit(rec)
} else {
err = errors.SetFile(err, m)
if strict || !errors.IsCorrupted(err) {
return
} else {
s.logf("manifest error: %v (skipped)", errors.SetFile(err, m))
}
}
rec.resetCompPtrs()
rec.resetAddedTables()
rec.resetDeletedTables()
}
switch {
case !rec.has(recComparer):
return newErrManifestCorrupted(m, "comparer", "missing")
case rec.comparer != s.icmp.uName():
return newErrManifestCorrupted(m, "comparer", fmt.Sprintf("mismatch: want '%s', got '%s'", s.icmp.uName(), rec.comparer))
case !rec.has(recNextFileNum):
return newErrManifestCorrupted(m, "next-file-num", "missing")
case !rec.has(recJournalNum):
return newErrManifestCorrupted(m, "journal-file-num", "missing")
case !rec.has(recSeqNum):
return newErrManifestCorrupted(m, "seq-num", "missing")
}
s.manifestFile = m
s.setVersion(staging.finish())
s.setNextFileNum(rec.nextFileNum)
s.recordCommited(rec)
return nil
}
func (db *DB) compactionTransact(name string, t compactionTransactInterface) {
defer func() {
if x := recover(); x != nil {
if x == errCompactionTransactExiting {
if err := t.revert(); err != nil {
db.logf("%s revert error %q", name, err)
}
}
panic(x)
}
}()
const (
backoffMin = 1 * time.Second
backoffMax = 8 * time.Second
backoffMul = 2 * time.Second
)
var (
backoff = backoffMin
backoffT = time.NewTimer(backoff)
lastCnt = compactionTransactCounter(0)
disableBackoff = db.s.o.GetDisableCompactionBackoff()
)
for n := 0; ; n++ {
// Check wether the DB is closed.
if db.isClosed() {
db.logf("%s exiting", name)
db.compactionExitTransact()
} else if n > 0 {
db.logf("%s retrying N·%d", name, n)
}
// Execute.
cnt := compactionTransactCounter(0)
err := t.run(&cnt)
if err != nil {
db.logf("%s error I·%d %q", name, cnt, err)
}
// Set compaction error status.
select {
case db.compErrSetC <- err:
case perr := <-db.compPerErrC:
if err != nil {
db.logf("%s exiting (persistent error %q)", name, perr)
db.compactionExitTransact()
}
case _, _ = <-db.closeC:
db.logf("%s exiting", name)
db.compactionExitTransact()
}
if err == nil {
return
}
if errors.IsCorrupted(err) {
db.logf("%s exiting (corruption detected)", name)
db.compactionExitTransact()
}
if !disableBackoff {
// Reset backoff duration if counter is advancing.
if cnt > lastCnt {
backoff = backoffMin
lastCnt = cnt
}
// Backoff.
backoffT.Reset(backoff)
if backoff < backoffMax {
backoff *= backoffMul
if backoff > backoffMax {
backoff = backoffMax
}
}
select {
case <-backoffT.C:
case _, _ = <-db.closeC:
db.logf("%s exiting", name)
db.compactionExitTransact()
}
}
}
}