func setAppliedIndex(
ctx context.Context,
eng engine.ReadWriter,
ms *enginepb.MVCCStats,
rangeID roachpb.RangeID,
appliedIndex,
leaseAppliedIndex uint64,
) error {
var value roachpb.Value
value.SetInt(int64(appliedIndex))
if err := engine.MVCCPut(ctx, eng, ms,
keys.RaftAppliedIndexKey(rangeID),
hlc.ZeroTimestamp,
value,
nil /* txn */); err != nil {
return err
}
value.SetInt(int64(leaseAppliedIndex))
return engine.MVCCPut(ctx, eng, ms,
keys.LeaseAppliedIndexKey(rangeID),
hlc.ZeroTimestamp,
value,
nil /* txn */)
}
// setAppliedIndex persists a new applied index.
func setAppliedIndex(eng engine.Engine, raftID proto.RaftID, appliedIndex uint64) error {
return engine.MVCCPut(eng, nil, /* stats */
keys.RaftAppliedIndexKey(raftID),
proto.ZeroTimestamp,
proto.Value{Bytes: encoding.EncodeUint64(nil, appliedIndex)},
nil /* txn */)
}
// setAppliedIndex persists a new applied index.
func setAppliedIndex(eng engine.Engine, rangeID roachpb.RangeID, appliedIndex uint64) error {
return engine.MVCCPut(eng, nil, /* stats */
keys.RaftAppliedIndexKey(rangeID),
roachpb.ZeroTimestamp,
roachpb.MakeValueFromBytes(encoding.EncodeUint64(nil, appliedIndex)),
nil /* txn */)
}
func setFrozenStatus(
eng engine.ReadWriter, ms *enginepb.MVCCStats, rangeID roachpb.RangeID, frozen bool,
) error {
var val roachpb.Value
val.SetBool(frozen)
return engine.MVCCPut(context.Background(), eng, ms,
keys.RangeFrozenStatusKey(rangeID), hlc.ZeroTimestamp, val, nil)
}
func setLastIndex(eng engine.ReadWriter, rangeID roachpb.RangeID, lastIndex uint64) error {
var value roachpb.Value
value.SetInt(int64(lastIndex))
return engine.MVCCPut(context.Background(), eng, nil, keys.RaftLastIndexKey(rangeID),
hlc.ZeroTimestamp,
value,
nil /* txn */)
}
// setLastIndex persists a new last index.
func setLastIndex(eng engine.Engine, rangeID roachpb.RangeID, lastIndex uint64) error {
var value roachpb.Value
value.SetInt(int64(lastIndex))
return engine.MVCCPut(eng, nil, keys.RaftLastIndexKey(rangeID),
roachpb.ZeroTimestamp,
value,
nil /* txn */)
}
// setAppliedIndex persists a new applied index.
func setAppliedIndex(eng engine.Engine, ms *engine.MVCCStats, rangeID roachpb.RangeID, appliedIndex uint64) error {
var value roachpb.Value
value.SetInt(int64(appliedIndex))
return engine.MVCCPut(eng, ms,
keys.RaftAppliedIndexKey(rangeID),
roachpb.ZeroTimestamp,
value,
nil /* txn */)
}
// Indirectly this tests that the transaction remembers the NodeID of the node
// being read from correctly, at least in this simple case. Not remembering the
// node would lead to thousands of transaction restarts and almost certainly a
// test timeout.
func TestUncertaintyRestarts(t *testing.T) {
{
db, eng, clock, mClock, _, transport, err := createTestDB()
if err != nil {
t.Fatal(err)
}
defer transport.Close()
// Set a large offset so that a busy restart-loop
// really shows. Also makes sure that the values
// we write in the future below don't actually
// wind up in the past.
offset := 4000 * time.Millisecond
clock.SetMaxOffset(offset)
key := proto.Key("key")
value := proto.Value{
Bytes: nil, // Set for each Put
}
// With the correct restart behaviour, we see only one restart
// and the value read is the very first one (as nothing else
// has been written)
wantedBytes := []byte("value-0")
txnOpts := &client.TransactionOptions{
Name: "uncertainty",
}
gr := &proto.GetResponse{}
i := -1
tErr := db.RunTransaction(txnOpts, func(txn *client.KV) error {
i++
mClock.Increment(1)
futureTS := clock.Now()
futureTS.WallTime++
value.Bytes = []byte(fmt.Sprintf("value-%d", i))
err = engine.MVCCPut(eng, nil, key, futureTS, value, nil)
if err != nil {
t.Fatal(err)
}
gr.Reset()
if err := txn.Call(proto.Get, proto.GetArgs(key), gr); err != nil {
return err
}
if gr.Value == nil || !bytes.Equal(gr.Value.Bytes, wantedBytes) {
t.Fatalf("%d: read wrong value: %v, wanted %q", i,
gr.Value, wantedBytes)
}
return nil
})
if i != 1 {
t.Errorf("txn restarted %d times, expected only one restart", i)
}
if tErr != nil {
t.Fatal(tErr)
}
}
}
// PutSequence writes a sequence number for the specified family.
func (rc *ResponseCache) PutSequence(e engine.Engine, family []byte, sequence int64, err error) error {
if sequence <= 0 || len(family) == 0 {
return errEmptyID
}
if !rc.shouldCacheError(err) {
return nil
}
// Write the response value to the engine.
key := keys.ResponseCacheKey(rc.rangeID, family)
var v roachpb.Value
v.SetInt(sequence)
return engine.MVCCPut(e, nil /* ms */, key, roachpb.ZeroTimestamp, v, nil /* txn */)
}
// append the given entries to the raft log. Takes the previous values of
// r.mu.lastIndex and r.mu.raftLogSize, and returns new values. We do this
// rather than modifying them directly because these modifications need to be
// atomic with the commit of the batch.
func (r *Replica) append(
ctx context.Context,
batch engine.ReadWriter,
prevLastIndex uint64,
prevRaftLogSize int64,
entries []raftpb.Entry,
) (uint64, int64, error) {
if len(entries) == 0 {
return prevLastIndex, prevRaftLogSize, nil
}
var diff enginepb.MVCCStats
var value roachpb.Value
for i := range entries {
ent := &entries[i]
key := keys.RaftLogKey(r.RangeID, ent.Index)
if err := value.SetProto(ent); err != nil {
return 0, 0, err
}
value.InitChecksum(key)
var err error
if ent.Index > prevLastIndex {
err = engine.MVCCBlindPut(ctx, batch, &diff, key, hlc.ZeroTimestamp, value, nil /* txn */)
} else {
err = engine.MVCCPut(ctx, batch, &diff, key, hlc.ZeroTimestamp, value, nil /* txn */)
}
if err != nil {
return 0, 0, err
}
}
// Delete any previously appended log entries which never committed.
lastIndex := entries[len(entries)-1].Index
for i := lastIndex + 1; i <= prevLastIndex; i++ {
err := engine.MVCCDelete(ctx, batch, &diff, keys.RaftLogKey(r.RangeID, i),
hlc.ZeroTimestamp, nil /* txn */)
if err != nil {
return 0, 0, err
}
}
if err := setLastIndex(ctx, batch, r.RangeID, lastIndex); err != nil {
return 0, 0, err
}
raftLogSize := prevRaftLogSize + diff.SysBytes
return lastIndex, raftLogSize, nil
}
// createRangeData creates sample range data in all possible areas of
// the key space. Returns a slice of the encoded keys of all created
// data.
func createRangeData(t *testing.T, r *Replica) []engine.MVCCKey {
ts0 := hlc.ZeroTimestamp
ts := hlc.Timestamp{WallTime: 1}
desc := r.Desc()
keyTSs := []struct {
key roachpb.Key
ts hlc.Timestamp
}{
{keys.AbortCacheKey(r.RangeID, testTxnID), ts0},
{keys.AbortCacheKey(r.RangeID, testTxnID2), ts0},
{keys.RangeFrozenStatusKey(r.RangeID), ts0},
{keys.RangeLastGCKey(r.RangeID), ts0},
{keys.RaftAppliedIndexKey(r.RangeID), ts0},
{keys.RaftTruncatedStateKey(r.RangeID), ts0},
{keys.LeaseAppliedIndexKey(r.RangeID), ts0},
{keys.RangeStatsKey(r.RangeID), ts0},
{keys.RaftHardStateKey(r.RangeID), ts0},
{keys.RaftLastIndexKey(r.RangeID), ts0},
{keys.RaftLogKey(r.RangeID, 1), ts0},
{keys.RaftLogKey(r.RangeID, 2), ts0},
{keys.RangeLastReplicaGCTimestampKey(r.RangeID), ts0},
{keys.RangeLastVerificationTimestampKey(r.RangeID), ts0},
{keys.RangeDescriptorKey(desc.StartKey), ts},
{keys.TransactionKey(roachpb.Key(desc.StartKey), uuid.NewV4()), ts0},
{keys.TransactionKey(roachpb.Key(desc.StartKey.Next()), uuid.NewV4()), ts0},
{keys.TransactionKey(fakePrevKey(desc.EndKey), uuid.NewV4()), ts0},
// TODO(bdarnell): KeyMin.Next() results in a key in the reserved system-local space.
// Once we have resolved https://github.com/cockroachdb/cockroach/issues/437,
// replace this with something that reliably generates the first valid key in the range.
//{r.Desc().StartKey.Next(), ts},
// The following line is similar to StartKey.Next() but adds more to the key to
// avoid falling into the system-local space.
{append(append([]byte{}, desc.StartKey...), '\x02'), ts},
{fakePrevKey(r.Desc().EndKey), ts},
}
keys := []engine.MVCCKey{}
for _, keyTS := range keyTSs {
if err := engine.MVCCPut(context.Background(), r.store.Engine(), nil, keyTS.key, keyTS.ts, roachpb.MakeValueFromString("value"), nil); err != nil {
t.Fatal(err)
}
keys = append(keys, engine.MVCCKey{Key: keyTS.key, Timestamp: keyTS.ts})
}
return keys
}
// Indirectly this tests that the transaction remembers the NodeID of the node
// being read from correctly, at least in this simple case. Not remembering the
// node would lead to thousands of transaction restarts and almost certainly a
// test timeout.
func TestUncertaintyRestarts(t *testing.T) {
defer leaktest.AfterTest(t)
s := createTestDB(t)
defer s.Stop()
// Set a large offset so that a busy restart-loop
// really shows. Also makes sure that the values
// we write in the future below don't actually
// wind up in the past.
offset := 4000 * time.Millisecond
s.Clock.SetMaxOffset(offset)
key := proto.Key("key")
value := proto.Value{
Bytes: nil, // Set for each Put
}
// With the correct restart behaviour, we see only one restart
// and the value read is the very first one (as nothing else
// has been written)
wantedBytes := []byte("value-0")
i := -1
tErr := s.DB.Txn(func(txn *client.Txn) error {
i++
s.Manual.Increment(1)
futureTS := s.Clock.Now()
futureTS.WallTime++
value.Bytes = []byte(fmt.Sprintf("value-%d", i))
if err := engine.MVCCPut(s.Eng, nil, key, futureTS, value, nil); err != nil {
t.Fatal(err)
}
gr, err := txn.Get(key)
if err != nil {
return err
}
if !gr.Exists() || !bytes.Equal(gr.ValueBytes(), wantedBytes) {
t.Fatalf("%d: read wrong value: %v, wanted %q", i, gr.Value, wantedBytes)
}
return nil
})
if i != 1 {
t.Errorf("txn restarted %d times, expected only one restart", i)
}
if tErr != nil {
t.Fatal(tErr)
}
}
// createRangeData creates sample range data in all possible areas of
// the key space. Returns a slice of the encoded keys of all created
// data.
func createRangeData(r *Replica, t *testing.T) []roachpb.EncodedKey {
ts0 := roachpb.ZeroTimestamp
ts := roachpb.Timestamp{WallTime: 1}
keyTSs := []struct {
key roachpb.Key
ts roachpb.Timestamp
}{
{keys.ResponseCacheKey(r.Desc().RangeID, &roachpb.ClientCmdID{WallTime: 1, Random: 1}), ts0},
{keys.ResponseCacheKey(r.Desc().RangeID, &roachpb.ClientCmdID{WallTime: 2, Random: 2}), ts0},
{keys.RaftHardStateKey(r.Desc().RangeID), ts0},
{keys.RaftLogKey(r.Desc().RangeID, 1), ts0},
{keys.RaftLogKey(r.Desc().RangeID, 2), ts0},
{keys.RangeGCMetadataKey(r.Desc().RangeID), ts0},
{keys.RangeLastVerificationTimestampKey(r.Desc().RangeID), ts0},
{keys.RangeStatsKey(r.Desc().RangeID), ts0},
{keys.RangeDescriptorKey(r.Desc().StartKey), ts},
{keys.TransactionKey(roachpb.Key(r.Desc().StartKey), []byte("1234")), ts0},
{keys.TransactionKey(roachpb.Key(r.Desc().StartKey.Next()), []byte("5678")), ts0},
{keys.TransactionKey(fakePrevKey(r.Desc().EndKey), []byte("2468")), ts0},
// TODO(bdarnell): KeyMin.Next() results in a key in the reserved system-local space.
// Once we have resolved https://github.com/cockroachdb/cockroach/issues/437,
// replace this with something that reliably generates the first valid key in the range.
//{r.Desc().StartKey.Next(), ts},
// The following line is similar to StartKey.Next() but adds more to the key to
// avoid falling into the system-local space.
{append(append([]byte{}, r.Desc().StartKey...), '\x01'), ts},
{fakePrevKey(r.Desc().EndKey), ts},
}
keys := []roachpb.EncodedKey{}
for _, keyTS := range keyTSs {
if err := engine.MVCCPut(r.store.Engine(), nil, keyTS.key, keyTS.ts, roachpb.MakeValueFromString("value"), nil); err != nil {
t.Fatal(err)
}
keys = append(keys, engine.MVCCEncodeKey(keyTS.key))
if !keyTS.ts.Equal(ts0) {
keys = append(keys, engine.MVCCEncodeVersionKey(keyTS.key, keyTS.ts))
}
}
return keys
}
// ApplySnapshot implements the multiraft.WriteableGroupStorage interface.
func (r *Range) ApplySnapshot(snap raftpb.Snapshot) error {
snapData := proto.RaftSnapshotData{}
err := gogoproto.Unmarshal(snap.Data, &snapData)
if err != nil {
return err
}
// First, save the HardState. The HardState must not be changed
// because it may record a previous vote cast by this node.
hardStateKey := keys.RaftHardStateKey(r.Desc().RaftID)
hardState, _, err := engine.MVCCGet(r.rm.Engine(), hardStateKey, proto.ZeroTimestamp, true /* consistent */, nil)
if err != nil {
return err
}
// Extract the updated range descriptor.
desc := snapData.RangeDescriptor
batch := r.rm.Engine().NewBatch()
defer batch.Close()
// Delete everything in the range and recreate it from the snapshot.
for iter := newRangeDataIterator(&desc, r.rm.Engine()); iter.Valid(); iter.Next() {
if err := batch.Clear(iter.Key()); err != nil {
return err
}
}
// Write the snapshot into the range.
for _, kv := range snapData.KV {
if err := batch.Put(kv.Key, kv.Value); err != nil {
return err
}
}
// Restore the saved HardState.
if hardState == nil {
err := engine.MVCCDelete(batch, nil, hardStateKey, proto.ZeroTimestamp, nil)
if err != nil {
return err
}
} else {
err := engine.MVCCPut(batch, nil, hardStateKey, proto.ZeroTimestamp, *hardState, nil)
if err != nil {
return err
}
}
// Read the leader lease.
lease, err := loadLeaderLease(batch, desc.RaftID)
if err != nil {
return err
}
// Copy range stats to new range.
oldStats := r.stats
r.stats, err = newRangeStats(desc.RaftID, batch)
if err != nil {
r.stats = oldStats
return err
}
// The next line sets the persisted last index to the last applied index.
// This is not a correctness issue, but means that we may have just
// transferred some entries we're about to re-request from the leader and
// overwrite.
// However, raft.MultiNode currently expects this behaviour, and the
// performance implications are not likely to be drastic. If our feelings
// about this ever change, we can add a LastIndex field to
// raftpb.SnapshotMetadata.
if err := setLastIndex(batch, r.Desc().RaftID, snap.Metadata.Index); err != nil {
return err
}
if err := batch.Commit(); err != nil {
return err
}
// As outlined above, last and applied index are the same after applying
// the snapshot.
atomic.StoreUint64(&r.lastIndex, snap.Metadata.Index)
atomic.StoreUint64(&r.appliedIndex, snap.Metadata.Index)
// Atomically update the descriptor and lease.
if err := r.setDesc(&desc); err != nil {
return err
}
atomic.StorePointer(&r.lease, unsafe.Pointer(lease))
return nil
}
// setLastIndex persists a new last index.
func setLastIndex(eng engine.Engine, raftID proto.RaftID, lastIndex uint64) error {
return engine.MVCCPut(eng, nil, keys.RaftLastIndexKey(raftID),
proto.ZeroTimestamp, proto.Value{
Bytes: encoding.EncodeUint64(nil, lastIndex),
}, nil)
}
// applySnapshot updates the replica based on the given snapshot.
func (r *Replica) applySnapshot(snap raftpb.Snapshot) error {
snapData := roachpb.RaftSnapshotData{}
err := proto.Unmarshal(snap.Data, &snapData)
if err != nil {
return err
}
rangeID := r.Desc().RangeID
// First, save the HardState. The HardState must not be changed
// because it may record a previous vote cast by this node.
hardStateKey := keys.RaftHardStateKey(rangeID)
hardState, _, err := engine.MVCCGet(r.store.Engine(), hardStateKey, roachpb.ZeroTimestamp, true /* consistent */, nil)
if err != nil {
return err
}
// Extract the updated range descriptor.
desc := snapData.RangeDescriptor
batch := r.store.Engine().NewBatch()
defer batch.Close()
// Delete everything in the range and recreate it from the snapshot.
iter := newReplicaDataIterator(&desc, r.store.Engine())
defer iter.Close()
for ; iter.Valid(); iter.Next() {
if err := batch.Clear(iter.Key()); err != nil {
return err
}
}
// Write the snapshot into the range.
for _, kv := range snapData.KV {
mvccKey := engine.MVCCKey{
Key: kv.Key,
Timestamp: kv.Timestamp,
}
if err := batch.Put(mvccKey, kv.Value); err != nil {
return err
}
}
// Restore the saved HardState.
if hardState == nil {
err := engine.MVCCDelete(batch, nil, hardStateKey, roachpb.ZeroTimestamp, nil)
if err != nil {
return err
}
} else {
err := engine.MVCCPut(batch, nil, hardStateKey, roachpb.ZeroTimestamp, *hardState, nil)
if err != nil {
return err
}
}
// Read the leader lease.
lease, err := loadLeaderLease(batch, desc.RangeID)
if err != nil {
return err
}
// Load updated range stats. The local newStats variable will be assigned
// to r.stats after the batch commits.
newStats, err := newRangeStats(desc.RangeID, batch)
if err != nil {
return err
}
// The next line sets the persisted last index to the last applied index.
// This is not a correctness issue, but means that we may have just
// transferred some entries we're about to re-request from the leader and
// overwrite.
// However, raft.MultiNode currently expects this behaviour, and the
// performance implications are not likely to be drastic. If our feelings
// about this ever change, we can add a LastIndex field to
// raftpb.SnapshotMetadata.
if err := setLastIndex(batch, rangeID, snap.Metadata.Index); err != nil {
return err
}
if err := batch.Commit(); err != nil {
return err
}
// Update the range stats.
r.stats.Replace(newStats)
// As outlined above, last and applied index are the same after applying
// the snapshot.
atomic.StoreUint64(&r.lastIndex, snap.Metadata.Index)
atomic.StoreUint64(&r.appliedIndex, snap.Metadata.Index)
// Atomically update the descriptor and lease.
if err := r.setDesc(&desc); err != nil {
return err
}
// Update other fields which are uninitialized or need updating.
// This may not happen if the system config has not yet been loaded.
// While config update will correctly set the fields, there is no order
// guarangee in ApplySnapshot.
// TODO: should go through the standard store lock when adding a replica.
if err := r.updateRangeInfo(); err != nil {
return err
}
atomic.StorePointer(&r.lease, unsafe.Pointer(lease))
return nil
}
// applySnapshot updates the replica based on the given snapshot.
// Returns the new last index.
func (r *Replica) applySnapshot(batch engine.Engine, snap raftpb.Snapshot) (uint64, error) {
snapData := roachpb.RaftSnapshotData{}
err := proto.Unmarshal(snap.Data, &snapData)
if err != nil {
return 0, err
}
rangeID := r.RangeID
// First, save the HardState. The HardState must not be changed
// because it may record a previous vote cast by this node. This is
// usually unnecessary because a snapshot is nearly always
// accompanied by a new HardState which incorporates both our former
// state and new information from the leader, but in the event that
// the HardState has not changed, we want to use our own previous
// HardState and not one that was transmitted via the snapshot.
hardStateKey := keys.RaftHardStateKey(rangeID)
hardState, _, err := engine.MVCCGet(batch, hardStateKey, roachpb.ZeroTimestamp, true /* consistent */, nil)
if err != nil {
return 0, err
}
// Extract the updated range descriptor.
desc := snapData.RangeDescriptor
// Delete everything in the range and recreate it from the snapshot.
// We need to delete any old Raft log entries here because any log entries
// that predate the snapshot will be orphaned and never truncated or GC'd.
iter := newReplicaDataIterator(&desc, batch, false /* !replicatedOnly */)
defer iter.Close()
for ; iter.Valid(); iter.Next() {
if err := batch.Clear(iter.Key()); err != nil {
return 0, err
}
}
// Determine the unreplicated key prefix so we can drop any
// unreplicated keys from the snapshot.
unreplicatedPrefix := keys.MakeRangeIDUnreplicatedPrefix(desc.RangeID)
// Write the snapshot into the range.
for _, kv := range snapData.KV {
if bytes.HasPrefix(kv.Key, unreplicatedPrefix) {
continue
}
mvccKey := engine.MVCCKey{
Key: kv.Key,
Timestamp: kv.Timestamp,
}
if err := batch.Put(mvccKey, kv.Value); err != nil {
return 0, err
}
}
// Write the snapshot's Raft log into the range.
if _, err := r.append(batch, 0, snapData.LogEntries); err != nil {
return 0, err
}
// Restore the saved HardState.
if hardState == nil {
err := engine.MVCCDelete(batch, nil, hardStateKey, roachpb.ZeroTimestamp, nil)
if err != nil {
return 0, err
}
} else {
err := engine.MVCCPut(batch, nil, hardStateKey, roachpb.ZeroTimestamp, *hardState, nil)
if err != nil {
return 0, err
}
}
// Read the leader lease.
lease, err := loadLeaderLease(batch, desc.RangeID)
if err != nil {
return 0, err
}
// Load updated range stats. The local newStats variable will be assigned
// to r.stats after the batch commits.
newStats, err := newRangeStats(desc.RangeID, batch)
if err != nil {
return 0, err
}
// The next line sets the persisted last index to the last applied index.
// This is not a correctness issue, but means that we may have just
// transferred some entries we're about to re-request from the leader and
// overwrite.
// However, raft.MultiNode currently expects this behaviour, and the
// performance implications are not likely to be drastic. If our feelings
// about this ever change, we can add a LastIndex field to
// raftpb.SnapshotMetadata.
if err := setLastIndex(batch, rangeID, snap.Metadata.Index); err != nil {
return 0, err
}
batch.Defer(func() {
// Update the range stats.
r.stats.Replace(newStats)
r.mu.Lock()
// As outlined above, last and applied index are the same after applying
// the snapshot.
r.mu.appliedIndex = snap.Metadata.Index
r.mu.leaderLease = lease
r.mu.Unlock()
// Update other fields which are uninitialized or need updating.
// This may not happen if the system config has not yet been loaded.
// While config update will correctly set the fields, there is no order
// guarantee in ApplySnapshot.
// TODO: should go through the standard store lock when adding a replica.
if err := r.updateRangeInfo(&desc); err != nil {
panic(err)
}
// Update the range descriptor. This is done last as this is the step that
// makes the Replica visible in the Store.
if err := r.setDesc(&desc); err != nil {
panic(err)
}
})
return snap.Metadata.Index, nil
}
// Put sets the value for a specified key.
func (r *Range) Put(batch engine.Engine, ms *engine.MVCCStats, args proto.PutRequest) (proto.PutResponse, error) {
var reply proto.PutResponse
return reply, engine.MVCCPut(batch, ms, args.Key, args.Timestamp, args.Value, args.Txn)
}
// TestUncertaintyObservedTimestampForwarding checks that when receiving an
// uncertainty restart on a node, the next attempt to read (at the increased
// timestamp) is free from uncertainty. See roachpb.Transaction for details.
func TestUncertaintyMaxTimestampForwarding(t *testing.T) {
defer leaktest.AfterTest(t)()
s := createTestDB(t)
disableOwnNodeCertain(s)
defer s.Stop()
// Large offset so that any value in the future is an uncertain read.
// Also makes sure that the values we write in the future below don't
// actually wind up in the past.
s.Clock.SetMaxOffset(50 * time.Second)
offsetNS := int64(100)
keySlow := roachpb.Key("slow")
keyFast := roachpb.Key("fast")
valSlow := []byte("wols")
valFast := []byte("tsaf")
// Write keySlow at now+offset, keyFast at now+2*offset
futureTS := s.Clock.Now()
futureTS.WallTime += offsetNS
val := roachpb.MakeValueFromBytes(valSlow)
if err := engine.MVCCPut(s.Eng, nil, keySlow, futureTS, val, nil); err != nil {
t.Fatal(err)
}
futureTS.WallTime += offsetNS
val.SetBytes(valFast)
if err := engine.MVCCPut(s.Eng, nil, keyFast, futureTS, val, nil); err != nil {
t.Fatal(err)
}
i := 0
if tErr := s.DB.Txn(func(txn *client.Txn) *roachpb.Error {
i++
// The first command serves to start a Txn, fixing the timestamps.
// There will be a restart, but this is idempotent.
if _, pErr := txn.Scan("t", roachpb.Key("t").Next(), 0); pErr != nil {
t.Fatal(pErr)
}
// This is a bit of a hack for the sake of this test: By visiting the
// node above, we've made a note of its clock, which allows us to
// prevent the restart. But we want to catch the restart, so reset the
// observed timestamps.
txn.Proto.ResetObservedTimestamps()
// The server's clock suddenly jumps ahead of keyFast's timestamp.
s.Manual.Set(2*offsetNS + 1)
// Now read slowKey first. It should read at 0, catch an uncertainty error,
// and get keySlow's timestamp in that error, but upgrade it to the larger
// node clock (which is ahead of keyFast as well). If the last part does
// not happen, the read of keyFast should fail (i.e. read nothing).
// There will be exactly one restart here.
if gr, pErr := txn.Get(keySlow); pErr != nil {
if i != 1 {
t.Fatalf("unexpected transaction error: %s", pErr)
}
return pErr
} else if !gr.Exists() || !bytes.Equal(gr.ValueBytes(), valSlow) {
t.Fatalf("read of %q returned %v, wanted value %q", keySlow, gr.Value, valSlow)
}
// The node should already be certain, so we expect no restart here
// and to read the correct key.
if gr, pErr := txn.Get(keyFast); pErr != nil {
t.Fatalf("second Get failed with %s", pErr)
} else if !gr.Exists() || !bytes.Equal(gr.ValueBytes(), valFast) {
t.Fatalf("read of %q returned %v, wanted value %q", keyFast, gr.Value, valFast)
}
return nil
}); tErr != nil {
t.Fatal(tErr)
}
}
// TestUncertaintyMaxTimestampForwarding checks that we correctly read from
// hosts which for which we control the uncertainty by checking that when a
// transaction restarts after an uncertain read, it will also take into account
// the target node's clock at the time of the failed read when forwarding the
// read timestamp.
// This is a prerequisite for being able to prevent further uncertainty
// restarts for that node and transaction without sacrificing correctness.
// See proto.Transaction.CertainNodes for details.
func TestUncertaintyMaxTimestampForwarding(t *testing.T) {
db, eng, clock, mClock, _, transport, err := createTestDB()
defer transport.Close()
// Large offset so that any value in the future is an uncertain read.
// Also makes sure that the values we write in the future below don't
// actually wind up in the past.
clock.SetMaxOffset(50000 * time.Millisecond)
txnOpts := &client.TransactionOptions{
Name: "uncertainty",
}
offsetNS := int64(100)
keySlow := proto.Key("slow")
keyFast := proto.Key("fast")
valSlow := []byte("wols")
valFast := []byte("tsaf")
// Write keySlow at now+offset, keyFast at now+2*offset
futureTS := clock.Now()
futureTS.WallTime += offsetNS
err = engine.MVCCPut(eng, nil, keySlow, futureTS,
proto.Value{Bytes: valSlow}, nil)
if err != nil {
t.Fatal(err)
}
futureTS.WallTime += offsetNS
err = engine.MVCCPut(eng, nil, keyFast, futureTS,
proto.Value{Bytes: valFast}, nil)
if err != nil {
t.Fatal(err)
}
i := 0
if tErr := db.RunTransaction(txnOpts, func(txn *client.KV) error {
i++
// The first command serves to start a Txn, fixing the timestamps.
// There will be a restart, but this is idempotent.
sr := &proto.ScanResponse{}
if err = txn.Call(proto.Scan, proto.ScanArgs(proto.Key("t"), proto.Key("t"),
0), sr); err != nil {
t.Fatal(err)
}
// The server's clock suddenly jumps ahead of keyFast's timestamp.
// There will be a restart, but this is idempotent.
mClock.Set(2*offsetNS + 1)
// Now read slowKey first. It should read at 0, catch an uncertainty error,
// and get keySlow's timestamp in that error, but upgrade it to the larger
// node clock (which is ahead of keyFast as well). If the last part does
// not happen, the read of keyFast should fail (i.e. read nothing).
// There will be exactly one restart here.
gr := &proto.GetResponse{}
if err = txn.Call(proto.Get, proto.GetArgs(keySlow), gr); err != nil {
if i != 1 {
t.Errorf("unexpected transaction error: %v", err)
}
return err
}
if gr.Value == nil || !bytes.Equal(gr.Value.Bytes, valSlow) {
t.Errorf("read of %q returned %v, wanted value %q", keySlow, gr.Value,
valSlow)
}
gr.Reset()
// The node should already be certain, so we expect no restart here
// and to read the correct key.
if err = txn.Call(proto.Get, proto.GetArgs(keyFast), gr); err != nil {
t.Errorf("second Get failed with %v", err)
}
if gr.Value == nil || !bytes.Equal(gr.Value.Bytes, valFast) {
t.Errorf("read of %q returned %v, wanted value %q", keyFast, gr.Value,
valFast)
}
return nil
}); tErr != nil {
t.Fatal(tErr)
}
}
// setLastIndex persists a new last index.
func setLastIndex(eng engine.Engine, rangeID roachpb.RangeID, lastIndex uint64) error {
return engine.MVCCPut(eng, nil, keys.RaftLastIndexKey(rangeID),
roachpb.ZeroTimestamp,
roachpb.MakeValueFromBytes(encoding.EncodeUint64(nil, lastIndex)), nil)
}
// Put sets the value for a specified key.
func (r *Range) Put(batch engine.Engine, ms *engine.MVCCStats, args *proto.PutRequest, reply *proto.PutResponse) {
err := engine.MVCCPut(batch, ms, args.Key, args.Timestamp, args.Value, args.Txn)
reply.SetGoError(err)
}
