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raft: move all unstable stuff into one struct for future cleanup

release-2.0
Xiang Li 2014-11-26 13:36:17 -08:00
parent 488f508505
commit 66252c7d62
4 changed files with 63 additions and 57 deletions
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84
raft/log.go
View File

@ -27,16 +27,10 @@ type raftLog struct {
// storage contains all stable entries since the last snapshot.
storage Storage
// the incoming unstable snapshot, if any.
unstableSnapshot *pb.Snapshot
// unstableEnts contains all entries that have not yet been written
// to storage.
unstableEnts []pb.Entry
// unstableEnts[i] has raft log position i+unstable. Note that
// unstable may be less than the highest log position in storage;
// this means that the next write to storage will truncate the log
// before persisting unstableEnts.
unstable uint64
// unstable contains all unstable entries and snapshot.
// they will be saved into storage.
unstable unstable
// committed is the highest log position that is known to be in
// stable storage on a quorum of nodes.
// Invariant: committed < unstable
@ -47,6 +41,18 @@ type raftLog struct {
applied uint64
}
// unstable.entris[i] has raft log position i+unstable.offset.
// Note that unstable.offset may be less than the highest log
// position in storage; this means that the next write to storage
// might need to truncate the log before persisting unstable.entries.
type unstable struct {
// the incoming unstable snapshot, if any.
snapshot *pb.Snapshot
// all entries that have not yet been written to storage.
entries []pb.Entry
offset uint64
}
// newLog returns log using the given storage. It recovers the log to the state
// that it just commits and applies the lastest snapshot.
func newLog(storage Storage) *raftLog {
@ -64,7 +70,7 @@ func newLog(storage Storage) *raftLog {
if err != nil {
panic(err) // TODO(bdarnell)
}
log.unstable = lastIndex + 1
log.unstable.offset = lastIndex + 1
// Initialize our committed and applied pointers to the time of the last compaction.
log.committed = firstIndex - 1
log.applied = firstIndex - 1
@ -73,7 +79,7 @@ func newLog(storage Storage) *raftLog {
}
func (l *raftLog) String() string {
return fmt.Sprintf("unstable=%d committed=%d applied=%d len(unstableEntries)=%d", l.unstable, l.committed, l.applied, len(l.unstableEnts))
return fmt.Sprintf("unstable=%d committed=%d applied=%d len(unstableEntries)=%d", l.unstable.offset, l.committed, l.applied, len(l.unstable.entries))
}
// maybeAppend returns (0, false) if the entries cannot be appended. Otherwise,
@ -100,15 +106,15 @@ func (l *raftLog) append(after uint64, ents ...pb.Entry) uint64 {
if after < l.committed {
log.Panicf("after(%d) is out of range [committed(%d)]", after, l.committed)
}
if after < l.unstable {
if after < l.unstable.offset {
// The log is being truncated to before our current unstable
// portion, so discard it and reset unstable.
l.unstableEnts = nil
l.unstable = after + 1
l.unstable.entries = nil
l.unstable.offset = after + 1
}
// Truncate any unstable entries that are being replaced, then
// append the new ones.
l.unstableEnts = append(l.unstableEnts[:after+1-l.unstable], ents...)
l.unstable.entries = append(l.unstable.entries[:after+1-l.unstable.offset], ents...)
return l.lastIndex()
}
@ -134,11 +140,11 @@ func (l *raftLog) findConflict(from uint64, ents []pb.Entry) uint64 {
}
func (l *raftLog) unstableEntries() []pb.Entry {
if len(l.unstableEnts) == 0 {
if len(l.unstable.entries) == 0 {
return nil
}
// copy unstable entries to an empty slice
return append([]pb.Entry{}, l.unstableEnts...)
return append([]pb.Entry{}, l.unstable.entries...)
}
// nextEnts returns all the available entries for execution.
@ -153,15 +159,15 @@ func (l *raftLog) nextEnts() (ents []pb.Entry) {
}
func (l *raftLog) snapshot() (pb.Snapshot, error) {
if l.unstableSnapshot != nil {
return *l.unstableSnapshot, nil
if l.unstable.snapshot != nil {
return *l.unstable.snapshot, nil
}
return l.storage.Snapshot()
}
func (l *raftLog) firstIndex() uint64 {
if l.unstableSnapshot != nil {
return l.unstableSnapshot.Metadata.Index + 1
if l.unstable.snapshot != nil {
return l.unstable.snapshot.Metadata.Index + 1
}
index, err := l.storage.FirstIndex()
if err != nil {
@ -171,7 +177,7 @@ func (l *raftLog) firstIndex() uint64 {
}
func (l *raftLog) lastIndex() uint64 {
return l.unstable + uint64(len(l.unstableEnts)) - 1
return l.unstable.offset + uint64(len(l.unstable.entries)) - 1
}
func (l *raftLog) commitTo(tocommit uint64) {
@ -195,12 +201,12 @@ func (l *raftLog) appliedTo(i uint64) {
}
func (l *raftLog) stableTo(i uint64) {
if i < l.unstable || i+1-l.unstable > uint64(len(l.unstableEnts)) {
if i < l.unstable.offset || i+1-l.unstable.offset > uint64(len(l.unstable.entries)) {
log.Panicf("stableTo(%d) is out of range [unstable(%d), len(unstableEnts)(%d)]",
i, l.unstable, len(l.unstableEnts))
i, l.unstable.offset, len(l.unstable.entries))
}
l.unstableEnts = l.unstableEnts[i+1-l.unstable:]
l.unstable = i + 1
l.unstable.entries = l.unstable.entries[i+1-l.unstable.offset:]
l.unstable.offset = i + 1
}
func (l *raftLog) lastTerm() uint64 {
@ -211,8 +217,8 @@ func (l *raftLog) term(i uint64) uint64 {
switch {
case i > l.lastIndex():
return 0
case i < l.unstable:
if snap := l.unstableSnapshot; snap != nil {
case i < l.unstable.offset:
if snap := l.unstable.snapshot; snap != nil {
if i == snap.Metadata.Index {
return snap.Metadata.Term
}
@ -228,7 +234,7 @@ func (l *raftLog) term(i uint64) uint64 {
panic(err) // TODO(bdarnell)
}
default:
return l.unstableEnts[i-l.unstable].Term
return l.unstable.entries[i-l.unstable.offset].Term
}
}
@ -265,9 +271,9 @@ func (l *raftLog) maybeCommit(maxIndex, term uint64) bool {
func (l *raftLog) restore(s pb.Snapshot) {
l.committed = s.Metadata.Index
l.unstable = l.committed
l.unstableEnts = []pb.Entry{{Index: s.Metadata.Index, Term: s.Metadata.Term}}
l.unstableSnapshot = &s
l.unstable.offset = l.committed
l.unstable.entries = []pb.Entry{{Index: s.Metadata.Index, Term: s.Metadata.Term}}
l.unstable.snapshot = &s
}
// slice returns a slice of log entries from lo through hi-1, inclusive.
@ -279,20 +285,20 @@ func (l *raftLog) slice(lo uint64, hi uint64) []pb.Entry {
return nil
}
var ents []pb.Entry
if lo < l.unstable {
storedEnts, err := l.storage.Entries(lo, min(hi, l.unstable))
if lo < l.unstable.offset {
storedEnts, err := l.storage.Entries(lo, min(hi, l.unstable.offset))
if err == ErrCompacted {
// This should never fail because it has been checked before.
log.Panicf("entries[%d:%d) from storage is out of bound", lo, min(hi, l.unstable))
log.Panicf("entries[%d:%d) from storage is out of bound", lo, min(hi, l.unstable.offset))
return nil
} else if err != nil {
panic(err) // TODO(bdarnell)
}
ents = append(ents, storedEnts...)
}
if hi > l.unstable {
firstUnstable := max(lo, l.unstable)
ents = append(ents, l.unstableEnts[firstUnstable-l.unstable:hi-l.unstable]...)
if hi > l.unstable.offset {
firstUnstable := max(lo, l.unstable.offset)
ents = append(ents, l.unstable.entries[firstUnstable-l.unstable.offset:hi-l.unstable.offset]...)
}
return ents
}

8
raft/log_test.go
View File

@ -143,7 +143,7 @@ func TestAppend(t *testing.T) {
if g := raftLog.entries(1); !reflect.DeepEqual(g, tt.wents) {
t.Errorf("#%d: logEnts = %+v, want %+v", i, g, tt.wents)
}
if g := raftLog.unstable; g != tt.wunstable {
if g := raftLog.unstable.offset; g != tt.wunstable {
t.Errorf("#%d: unstable = %d, want %d", i, g, tt.wunstable)
}
}
@ -398,7 +398,7 @@ func TestUnstableEnts(t *testing.T) {
t.Errorf("#%d: unstableEnts = %+v, want %+v", i, ents, tt.wents)
}
w := previousEnts[len(previousEnts)-1].Index + 1
if g := raftLog.unstable; g != w {
if g := raftLog.unstable.offset; g != w {
t.Errorf("#%d: unstable = %d, want %d", i, g, w)
}
}
@ -448,7 +448,7 @@ func TestStableTo(t *testing.T) {
raftLog := newLog(NewMemoryStorage())
raftLog.append(0, []pb.Entry{{}, {}}...)
raftLog.stableTo(tt.stable)
if raftLog.unstable != tt.wunstable {
if raftLog.unstable.offset != tt.wunstable {
t.Errorf("#%d: unstable = %d, want %d", i, raftLog.unstable, tt.wunstable)
}
}
@ -520,7 +520,7 @@ func TestLogRestore(t *testing.T) {
if raftLog.committed != index {
t.Errorf("comitted = %d, want %d", raftLog.committed, index)
}
if raftLog.unstable != index+1 {
if raftLog.unstable.offset != index+1 {
t.Errorf("unstable = %d, want %d", raftLog.unstable, index+1)
}
if raftLog.term(index) != term {

8
raft/node.go
View File

@ -306,8 +306,8 @@ func (n *node) run(r *raft) {
r.raftLog.stableTo(prevLastUnstablei)
havePrevLastUnstablei = false
}
if r.raftLog.unstableSnapshot != nil && r.raftLog.unstableSnapshot.Metadata.Index == prevSnapi {
r.raftLog.unstableSnapshot = nil
if r.raftLog.unstable.snapshot != nil && r.raftLog.unstable.snapshot.Metadata.Index == prevSnapi {
r.raftLog.unstable.snapshot = nil
}
advancec = nil
case <-n.stop:
@ -405,8 +405,8 @@ func newReady(r *raft, prevSoftSt *SoftState, prevHardSt pb.HardState) Ready {
if !isHardStateEqual(r.HardState, prevHardSt) {
rd.HardState = r.HardState
}
if r.raftLog.unstableSnapshot != nil {
rd.Snapshot = *r.raftLog.unstableSnapshot
if r.raftLog.unstable.snapshot != nil {
rd.Snapshot = *r.raftLog.unstable.snapshot
}
return rd
}

20
raft/raft_test.go
View File

@ -337,7 +337,7 @@ func TestDuelingCandidates(t *testing.T) {
wlog := &raftLog{
storage: &MemoryStorage{ents: []pb.Entry{{}, pb.Entry{Data: nil, Term: 1, Index: 1}}},
committed: 1,
unstable: 2,
unstable: unstable{offset: 2},
}
tests := []struct {
sm *raft
@ -394,7 +394,7 @@ func TestCandidateConcede(t *testing.T) {
storage: &MemoryStorage{
ents: []pb.Entry{{}, {Data: nil, Term: 1, Index: 1}, {Term: 1, Index: 2, Data: data}},
},
unstable: 3,
unstable: unstable{offset: 3},
committed: 2,
})
for i, p := range tt.peers {
@ -435,7 +435,7 @@ func TestOldMessages(t *testing.T) {
{Data: nil, Term: 2, Index: 2}, {Data: nil, Term: 3, Index: 3},
},
},
unstable: 4,
unstable: unstable{offset: 4},
committed: 3,
}
base := ltoa(l)
@ -492,7 +492,7 @@ func TestProposal(t *testing.T) {
storage: &MemoryStorage{
ents: []pb.Entry{{}, {Data: nil, Term: 1, Index: 1}, {Term: 1, Index: 2, Data: data}},
},
unstable: 3,
unstable: unstable{offset: 3},
committed: 2}
}
base := ltoa(wantLog)
@ -531,7 +531,7 @@ func TestProposalByProxy(t *testing.T) {
storage: &MemoryStorage{
ents: []pb.Entry{{}, {Data: nil, Term: 1, Index: 1}, {Term: 1, Data: data, Index: 2}},
},
unstable: 3,
unstable: unstable{offset: 3},
committed: 2}
base := ltoa(wantLog)
for i, p := range tt.peers {
@ -585,7 +585,7 @@ func TestCommit(t *testing.T) {
prs[uint64(j)] = &progress{tt.matches[j], tt.matches[j] + 1}
}
sm := &raft{
raftLog: &raftLog{storage: &MemoryStorage{ents: tt.logs}, unstable: uint64(len(tt.logs))},
raftLog: &raftLog{storage: &MemoryStorage{ents: tt.logs}, unstable: unstable{offset: uint64(len(tt.logs))}},
prs: prs,
HardState: pb.HardState{Term: tt.smTerm},
}
@ -681,7 +681,7 @@ func TestHandleMsgApp(t *testing.T) {
raftLog: &raftLog{
committed: 0,
storage: &MemoryStorage{ents: []pb.Entry{{}, {Term: 1}, {Term: 2}}},
unstable: 3,
unstable: unstable{offset: 3},
},
}
@ -781,7 +781,7 @@ func TestRecvMsgVote(t *testing.T) {
sm.HardState = pb.HardState{Vote: tt.voteFor}
sm.raftLog = &raftLog{
storage: &MemoryStorage{ents: []pb.Entry{{}, {Index: 1, Term: 2}, {Index: 2, Term: 2}}},
unstable: 3,
unstable: unstable{offset: 3},
}
sm.Step(pb.Message{Type: pb.MsgVote, From: 2, Index: tt.i, LogTerm: tt.term})
@ -929,7 +929,7 @@ func TestLeaderAppResp(t *testing.T) {
sm := newRaft(1, []uint64{1, 2, 3}, 10, 1, NewMemoryStorage())
sm.raftLog = &raftLog{
storage: &MemoryStorage{ents: []pb.Entry{{}, {Index: 1, Term: 0}, {Index: 2, Term: 1}}},
unstable: 3,
unstable: unstable{offset: 3},
}
sm.becomeCandidate()
sm.becomeLeader()
@ -1351,7 +1351,7 @@ func ents(terms ...uint64) *raft {
sm := &raft{
raftLog: &raftLog{
storage: &MemoryStorage{ents: ents},
unstable: uint64(len(ents)),
unstable: unstable{offset: uint64(len(ents))},
},
}
sm.reset(0)