diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/version.go')
| -rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/version.go | 528 |
1 files changed, 528 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/version.go b/vendor/github.com/syndtr/goleveldb/leveldb/version.go new file mode 100644 index 0000000..73f272a --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/version.go @@ -0,0 +1,528 @@ +// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com> +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +package leveldb + +import ( + "fmt" + "sync/atomic" + "unsafe" + + "github.com/syndtr/goleveldb/leveldb/iterator" + "github.com/syndtr/goleveldb/leveldb/opt" + "github.com/syndtr/goleveldb/leveldb/util" +) + +type tSet struct { + level int + table *tFile +} + +type version struct { + s *session + + levels []tFiles + + // Level that should be compacted next and its compaction score. + // Score < 1 means compaction is not strictly needed. These fields + // are initialized by computeCompaction() + cLevel int + cScore float64 + + cSeek unsafe.Pointer + + closing bool + ref int + released bool +} + +func newVersion(s *session) *version { + return &version{s: s} +} + +func (v *version) incref() { + if v.released { + panic("already released") + } + + v.ref++ + if v.ref == 1 { + // Incr file ref. + for _, tt := range v.levels { + for _, t := range tt { + v.s.addFileRef(t.fd, 1) + } + } + } +} + +func (v *version) releaseNB() { + v.ref-- + if v.ref > 0 { + return + } else if v.ref < 0 { + panic("negative version ref") + } + + for _, tt := range v.levels { + for _, t := range tt { + if v.s.addFileRef(t.fd, -1) == 0 { + v.s.tops.remove(t) + } + } + } + + v.released = true +} + +func (v *version) release() { + v.s.vmu.Lock() + v.releaseNB() + v.s.vmu.Unlock() +} + +func (v *version) walkOverlapping(aux tFiles, ikey internalKey, f func(level int, t *tFile) bool, lf func(level int) bool) { + ukey := ikey.ukey() + + // Aux level. + if aux != nil { + for _, t := range aux { + if t.overlaps(v.s.icmp, ukey, ukey) { + if !f(-1, t) { + return + } + } + } + + if lf != nil && !lf(-1) { + return + } + } + + // Walk tables level-by-level. + for level, tables := range v.levels { + if len(tables) == 0 { + continue + } + + if level == 0 { + // Level-0 files may overlap each other. Find all files that + // overlap ukey. + for _, t := range tables { + if t.overlaps(v.s.icmp, ukey, ukey) { + if !f(level, t) { + return + } + } + } + } else { + if i := tables.searchMax(v.s.icmp, ikey); i < len(tables) { + t := tables[i] + if v.s.icmp.uCompare(ukey, t.imin.ukey()) >= 0 { + if !f(level, t) { + return + } + } + } + } + + if lf != nil && !lf(level) { + return + } + } +} + +func (v *version) get(aux tFiles, ikey internalKey, ro *opt.ReadOptions, noValue bool) (value []byte, tcomp bool, err error) { + if v.closing { + return nil, false, ErrClosed + } + + ukey := ikey.ukey() + + var ( + tset *tSet + tseek bool + + // Level-0. + zfound bool + zseq uint64 + zkt keyType + zval []byte + ) + + err = ErrNotFound + + // Since entries never hop across level, finding key/value + // in smaller level make later levels irrelevant. + v.walkOverlapping(aux, ikey, func(level int, t *tFile) bool { + if level >= 0 && !tseek { + if tset == nil { + tset = &tSet{level, t} + } else { + tseek = true + } + } + + var ( + fikey, fval []byte + ferr error + ) + if noValue { + fikey, ferr = v.s.tops.findKey(t, ikey, ro) + } else { + fikey, fval, ferr = v.s.tops.find(t, ikey, ro) + } + + switch ferr { + case nil: + case ErrNotFound: + return true + default: + err = ferr + return false + } + + if fukey, fseq, fkt, fkerr := parseInternalKey(fikey); fkerr == nil { + if v.s.icmp.uCompare(ukey, fukey) == 0 { + // Level <= 0 may overlaps each-other. + if level <= 0 { + if fseq >= zseq { + zfound = true + zseq = fseq + zkt = fkt + zval = fval + } + } else { + switch fkt { + case keyTypeVal: + value = fval + err = nil + case keyTypeDel: + default: + panic("leveldb: invalid internalKey type") + } + return false + } + } + } else { + err = fkerr + return false + } + + return true + }, func(level int) bool { + if zfound { + switch zkt { + case keyTypeVal: + value = zval + err = nil + case keyTypeDel: + default: + panic("leveldb: invalid internalKey type") + } + return false + } + + return true + }) + + if tseek && tset.table.consumeSeek() <= 0 { + tcomp = atomic.CompareAndSwapPointer(&v.cSeek, nil, unsafe.Pointer(tset)) + } + + return +} + +func (v *version) sampleSeek(ikey internalKey) (tcomp bool) { + var tset *tSet + + v.walkOverlapping(nil, ikey, func(level int, t *tFile) bool { + if tset == nil { + tset = &tSet{level, t} + return true + } + if tset.table.consumeSeek() <= 0 { + tcomp = atomic.CompareAndSwapPointer(&v.cSeek, nil, unsafe.Pointer(tset)) + } + return false + }, nil) + + return +} + +func (v *version) getIterators(slice *util.Range, ro *opt.ReadOptions) (its []iterator.Iterator) { + strict := opt.GetStrict(v.s.o.Options, ro, opt.StrictReader) + for level, tables := range v.levels { + if level == 0 { + // Merge all level zero files together since they may overlap. + for _, t := range tables { + its = append(its, v.s.tops.newIterator(t, slice, ro)) + } + } else if len(tables) != 0 { + its = append(its, iterator.NewIndexedIterator(tables.newIndexIterator(v.s.tops, v.s.icmp, slice, ro), strict)) + } + } + return +} + +func (v *version) newStaging() *versionStaging { + return &versionStaging{base: v} +} + +// Spawn a new version based on this version. +func (v *version) spawn(r *sessionRecord) *version { + staging := v.newStaging() + staging.commit(r) + return staging.finish() +} + +func (v *version) fillRecord(r *sessionRecord) { + for level, tables := range v.levels { + for _, t := range tables { + r.addTableFile(level, t) + } + } +} + +func (v *version) tLen(level int) int { + if level < len(v.levels) { + return len(v.levels[level]) + } + return 0 +} + +func (v *version) offsetOf(ikey internalKey) (n int64, err error) { + for level, tables := range v.levels { + for _, t := range tables { + if v.s.icmp.Compare(t.imax, ikey) <= 0 { + // Entire file is before "ikey", so just add the file size + n += t.size + } else if v.s.icmp.Compare(t.imin, ikey) > 0 { + // Entire file is after "ikey", so ignore + if level > 0 { + // Files other than level 0 are sorted by meta->min, so + // no further files in this level will contain data for + // "ikey". + break + } + } else { + // "ikey" falls in the range for this table. Add the + // approximate offset of "ikey" within the table. + if m, err := v.s.tops.offsetOf(t, ikey); err == nil { + n += m + } else { + return 0, err + } + } + } + } + + return +} + +func (v *version) pickMemdbLevel(umin, umax []byte, maxLevel int) (level int) { + if maxLevel > 0 { + if len(v.levels) == 0 { + return maxLevel + } + if !v.levels[0].overlaps(v.s.icmp, umin, umax, true) { + var overlaps tFiles + for ; level < maxLevel; level++ { + if pLevel := level + 1; pLevel >= len(v.levels) { + return maxLevel + } else if v.levels[pLevel].overlaps(v.s.icmp, umin, umax, false) { + break + } + if gpLevel := level + 2; gpLevel < len(v.levels) { + overlaps = v.levels[gpLevel].getOverlaps(overlaps, v.s.icmp, umin, umax, false) + if overlaps.size() > int64(v.s.o.GetCompactionGPOverlaps(level)) { + break + } + } + } + } + } + return +} + +func (v *version) computeCompaction() { + // Precomputed best level for next compaction + bestLevel := int(-1) + bestScore := float64(-1) + + statFiles := make([]int, len(v.levels)) + statSizes := make([]string, len(v.levels)) + statScore := make([]string, len(v.levels)) + statTotSize := int64(0) + + for level, tables := range v.levels { + var score float64 + size := tables.size() + if level == 0 { + // We treat level-0 specially by bounding the number of files + // instead of number of bytes for two reasons: + // + // (1) With larger write-buffer sizes, it is nice not to do too + // many level-0 compaction. + // + // (2) The files in level-0 are merged on every read and + // therefore we wish to avoid too many files when the individual + // file size is small (perhaps because of a small write-buffer + // setting, or very high compression ratios, or lots of + // overwrites/deletions). + score = float64(len(tables)) / float64(v.s.o.GetCompactionL0Trigger()) + } else { + score = float64(size) / float64(v.s.o.GetCompactionTotalSize(level)) + } + + if score > bestScore { + bestLevel = level + bestScore = score + } + + statFiles[level] = len(tables) + statSizes[level] = shortenb(int(size)) + statScore[level] = fmt.Sprintf("%.2f", score) + statTotSize += size + } + + v.cLevel = bestLevel + v.cScore = bestScore + + v.s.logf("version@stat F·%v S·%s%v Sc·%v", statFiles, shortenb(int(statTotSize)), statSizes, statScore) +} + +func (v *version) needCompaction() bool { + return v.cScore >= 1 || atomic.LoadPointer(&v.cSeek) != nil +} + +type tablesScratch struct { + added map[int64]atRecord + deleted map[int64]struct{} +} + +type versionStaging struct { + base *version + levels []tablesScratch +} + +func (p *versionStaging) getScratch(level int) *tablesScratch { + if level >= len(p.levels) { + newLevels := make([]tablesScratch, level+1) + copy(newLevels, p.levels) + p.levels = newLevels + } + return &(p.levels[level]) +} + +func (p *versionStaging) commit(r *sessionRecord) { + // Deleted tables. + for _, r := range r.deletedTables { + scratch := p.getScratch(r.level) + if r.level < len(p.base.levels) && len(p.base.levels[r.level]) > 0 { + if scratch.deleted == nil { + scratch.deleted = make(map[int64]struct{}) + } + scratch.deleted[r.num] = struct{}{} + } + if scratch.added != nil { + delete(scratch.added, r.num) + } + } + + // New tables. + for _, r := range r.addedTables { + scratch := p.getScratch(r.level) + if scratch.added == nil { + scratch.added = make(map[int64]atRecord) + } + scratch.added[r.num] = r + if scratch.deleted != nil { + delete(scratch.deleted, r.num) + } + } +} + +func (p *versionStaging) finish() *version { + // Build new version. + nv := newVersion(p.base.s) + numLevel := len(p.levels) + if len(p.base.levels) > numLevel { + numLevel = len(p.base.levels) + } + nv.levels = make([]tFiles, numLevel) + for level := 0; level < numLevel; level++ { + var baseTabels tFiles + if level < len(p.base.levels) { + baseTabels = p.base.levels[level] + } + + if level < len(p.levels) { + scratch := p.levels[level] + + var nt tFiles + // Prealloc list if possible. + if n := len(baseTabels) + len(scratch.added) - len(scratch.deleted); n > 0 { + nt = make(tFiles, 0, n) + } + + // Base tables. + for _, t := range baseTabels { + if _, ok := scratch.deleted[t.fd.Num]; ok { + continue + } + if _, ok := scratch.added[t.fd.Num]; ok { + continue + } + nt = append(nt, t) + } + + // New tables. + for _, r := range scratch.added { + nt = append(nt, tableFileFromRecord(r)) + } + + if len(nt) != 0 { + // Sort tables. + if level == 0 { + nt.sortByNum() + } else { + nt.sortByKey(p.base.s.icmp) + } + + nv.levels[level] = nt + } + } else { + nv.levels[level] = baseTabels + } + } + + // Trim levels. + n := len(nv.levels) + for ; n > 0 && nv.levels[n-1] == nil; n-- { + } + nv.levels = nv.levels[:n] + + // Compute compaction score for new version. + nv.computeCompaction() + + return nv +} + +type versionReleaser struct { + v *version + once bool +} + +func (vr *versionReleaser) Release() { + v := vr.v + v.s.vmu.Lock() + if !vr.once { + v.releaseNB() + vr.once = true + } + v.s.vmu.Unlock() +} |