// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
// Run a one-off transaction with that single command.
if log.V(1) {
log.Infof("%s: auto-wrapping in txn and re-executing: ", ba)
}
tmpDB := client.NewDBWithPriority(tc, ba.UserPriority)
var br *roachpb.BatchResponse
pErr := tmpDB.Txn(func(txn *client.Txn) *roachpb.Error {
txn.SetDebugName("auto-wrap", 0)
b := txn.NewBatch()
b.MaxScanResults = ba.MaxScanResults
for _, arg := range ba.Requests {
req := arg.GetInner()
b.InternalAddRequest(req)
}
var pErr *roachpb.Error
br, pErr = txn.CommitInBatchWithResponse(b)
return pErr
})
if pErr != nil {
return nil, pErr
}
br.Txn = nil // hide the evidence
return br, nil
}
// TestSender mocks out some of the txn coordinator sender's
// functionality. It responds to PutRequests using testPutResp.
func newTestSender(pre, post func(roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error)) SenderFunc {
txnKey := roachpb.Key("test-txn")
txnID := uuid.NewV4()
return func(_ context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
if ba.UserPriority == 0 {
ba.UserPriority = 1
}
if ba.Txn != nil && ba.Txn.ID == nil {
ba.Txn.Key = txnKey
ba.Txn.ID = txnID
}
var br *roachpb.BatchResponse
var pErr *roachpb.Error
if pre != nil {
br, pErr = pre(ba)
} else {
br = ba.CreateReply()
}
if pErr != nil {
return nil, pErr
}
var writing bool
status := roachpb.PENDING
for i, req := range ba.Requests {
args := req.GetInner()
if _, ok := args.(*roachpb.PutRequest); ok {
testPutRespCopy := testPutResp
union := &br.Responses[i] // avoid operating on copy
union.MustSetInner(&testPutRespCopy)
}
if roachpb.IsTransactionWrite(args) {
writing = true
}
}
if args, ok := ba.GetArg(roachpb.EndTransaction); ok {
et := args.(*roachpb.EndTransactionRequest)
writing = true
if et.Commit {
status = roachpb.COMMITTED
} else {
status = roachpb.ABORTED
}
}
if ba.Txn != nil {
txnClone := ba.Txn.Clone()
br.Txn = &txnClone
if pErr == nil {
br.Txn.Writing = writing
br.Txn.Status = status
}
}
if post != nil {
br, pErr = post(ba)
}
return br, pErr
}
}
// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
// Run a one-off transaction with that single command.
if log.V(1) {
log.Infof(tc.ctx, "%s: auto-wrapping in txn and re-executing: ", ba)
}
// TODO(bdarnell): need to be able to pass other parts of DBContext
// through here.
dbCtx := client.DefaultDBContext()
dbCtx.UserPriority = ba.UserPriority
tmpDB := client.NewDBWithContext(tc, dbCtx)
var br *roachpb.BatchResponse
err := tmpDB.Txn(context.TODO(), func(txn *client.Txn) error {
txn.SetDebugName("auto-wrap", 0)
b := txn.NewBatch()
b.Header = ba.Header
for _, arg := range ba.Requests {
req := arg.GetInner()
b.AddRawRequest(req)
}
err := txn.CommitInBatch(b)
br = b.RawResponse()
return err
})
if err != nil {
return nil, roachpb.NewError(err)
}
br.Txn = nil // hide the evidence
return br, nil
}
// TestSender mocks out some of the txn coordinator sender's
// functionality. It responds to PutRequests using testPutResp.
func newTestSender(pre, post func(roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error)) SenderFunc {
txnKey := roachpb.Key("test-txn")
txnID := []byte(uuid.NewUUID4())
return func(_ context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
ba.UserPriority = 1
if ba.Txn != nil && len(ba.Txn.ID) == 0 {
ba.Txn.Key = txnKey
ba.Txn.ID = txnID
}
var br *roachpb.BatchResponse
var pErr *roachpb.Error
if pre != nil {
br, pErr = pre(ba)
} else {
br = ba.CreateReply()
}
if pErr != nil {
return nil, pErr
}
var writing bool
status := roachpb.PENDING
for i, req := range ba.Requests {
args := req.GetInner()
if _, ok := args.(*roachpb.PutRequest); ok {
if !br.Responses[i].SetValue(proto.Clone(testPutResp).(roachpb.Response)) {
panic("failed to set put response")
}
}
if roachpb.IsTransactionWrite(args) {
writing = true
}
}
if args, ok := ba.GetArg(roachpb.EndTransaction); ok {
et := args.(*roachpb.EndTransactionRequest)
writing = true
if et.Commit {
status = roachpb.COMMITTED
} else {
status = roachpb.ABORTED
}
}
if ba.Txn != nil {
txnClone := ba.Txn.Clone()
br.Txn = &txnClone
if pErr == nil {
br.Txn.Writing = writing
br.Txn.Status = status
}
}
if post != nil {
br, pErr = post(ba)
}
return br, pErr
}
}
func newTestSender(pre, post func(roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error)) SenderFunc {
txnKey := roachpb.Key("test-txn")
txnID := []byte(uuid.NewUUID4())
return func(_ context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
ba.UserPriority = proto.Int32(-1)
if ba.Txn != nil && len(ba.Txn.ID) == 0 {
ba.Txn.Key = txnKey
ba.Txn.ID = txnID
}
var br *roachpb.BatchResponse
var pErr *roachpb.Error
if pre != nil {
br, pErr = pre(ba)
} else {
br = ba.CreateReply()
}
if pErr != nil {
return nil, pErr
}
var writing bool
status := roachpb.PENDING
if _, ok := ba.GetArg(roachpb.Put); ok {
br.Add(proto.Clone(testPutResp).(roachpb.Response))
writing = true
}
if args, ok := ba.GetArg(roachpb.EndTransaction); ok {
et := args.(*roachpb.EndTransactionRequest)
writing = true
if et.Commit {
status = roachpb.COMMITTED
} else {
status = roachpb.ABORTED
}
}
br.Txn = proto.Clone(ba.Txn).(*roachpb.Transaction)
if br.Txn != nil && pErr == nil {
br.Txn.Writing = writing
br.Txn.Status = status
}
if post != nil {
br, pErr = post(ba)
}
return br, pErr
}
}
// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba roachpb.BatchRequest, br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
trace := tracer.FromCtx(ctx)
newTxn := &roachpb.Transaction{}
newTxn.Update(ba.GetTxn())
// TODO(tamird): remove this clone. It's currently needed to avoid race conditions.
pErr = proto.Clone(pErr).(*roachpb.Error)
err := pErr.GoError()
// TODO(bdarnell): We're writing to errors here (and where using ErrorWithIndex);
// since there's no concept of ownership copy-on-write is always preferable.
switch t := err.(type) {
case nil:
newTxn.Update(br.Txn)
// Move txn timestamp forward to response timestamp if applicable.
// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
// Looks like this isn't necessary any more, nor did it prevent a bug
// referenced in a TODO there.
newTxn.Timestamp.Forward(br.Timestamp)
case *roachpb.TransactionStatusError:
// Likely already committed or more obscure errors such as epoch or
// timestamp regressions; consider txn dead.
defer tc.cleanupTxn(trace, t.Txn)
case *roachpb.OpRequiresTxnError:
panic("OpRequiresTxnError must not happen at this level")
case *roachpb.ReadWithinUncertaintyIntervalError:
// Mark the host as certain. See the protobuf comment for
// Transaction.CertainNodes for details.
if t.NodeID == 0 {
panic("no replica set in header on uncertainty restart")
}
newTxn.Update(&t.Txn)
newTxn.CertainNodes.Add(t.NodeID)
// If the reader encountered a newer write within the uncertainty
// interval, move the timestamp forward, just past that write or
// up to MaxTimestamp, whichever comes first.
candidateTS := newTxn.MaxTimestamp
candidateTS.Backward(t.ExistingTimestamp.Add(0, 1))
newTxn.Timestamp.Forward(candidateTS)
newTxn.Restart(ba.GetUserPriority(), newTxn.Priority, newTxn.Timestamp)
t.Txn = *newTxn
case *roachpb.TransactionAbortedError:
trace.SetError()
newTxn.Update(&t.Txn)
// Increase timestamp if applicable.
newTxn.Timestamp.Forward(t.Txn.Timestamp)
newTxn.Priority = t.Txn.Priority
t.Txn = *newTxn
// Clean up the freshly aborted transaction in defer(), avoiding a
// race with the state update below.
defer tc.cleanupTxn(trace, t.Txn)
case *roachpb.TransactionPushError:
newTxn.Update(t.Txn)
// Increase timestamp if applicable, ensuring that we're
// just ahead of the pushee.
newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
newTxn.Restart(ba.GetUserPriority(), t.PusheeTxn.Priority-1, newTxn.Timestamp)
t.Txn = newTxn
case *roachpb.TransactionRetryError:
newTxn.Update(&t.Txn)
newTxn.Restart(ba.GetUserPriority(), t.Txn.Priority, newTxn.Timestamp)
t.Txn = *newTxn
case roachpb.TransactionRestartError:
// Assertion: The above cases should exhaust all ErrorDetails which
// carry a Transaction.
if pErr.Detail != nil {
panic(fmt.Sprintf("unhandled TransactionRestartError %T", err))
}
default:
trace.SetError()
}
return func() *roachpb.Error {
if len(newTxn.ID) <= 0 {
return pErr
}
id := string(newTxn.ID)
tc.Lock()
defer tc.Unlock()
txnMeta := tc.txns[id]
// For successful transactional requests, keep the written intents and
// the updated transaction record to be sent along with the reply.
// The transaction metadata is created with the first writing operation.
// A tricky edge case is that of a transaction which "fails" on the
// first writing request, but actually manages to write some intents
// (for example, due to being multi-range). In this case, there will
// be an error, but the transaction will be marked as Writing and the
// coordinator must track the state, for the client's retry will be
// performed with a Writing transaction which the coordinator rejects
// unless it is tracking it (on top of it making sense to track it;
// after all, it **has** laid down intents and only the coordinator
// can augment a potential EndTransaction call).
// consider re-using those.
if intents := ba.GetIntents(); len(intents) > 0 && (err == nil || newTxn.Writing) {
if txnMeta == nil {
if !newTxn.Writing {
panic("txn with intents marked as non-writing")
}
txnMeta = &txnMetadata{
txn: *newTxn,
keys: cache.NewIntervalCache(cache.Config{Policy: cache.CacheNone}),
firstUpdateNanos: tc.clock.PhysicalNow(),
lastUpdateNanos: tc.clock.PhysicalNow(),
timeoutDuration: tc.clientTimeout,
txnEnd: make(chan struct{}),
}
tc.txns[id] = txnMeta
// If the transaction is already over, there's no point in
// launching a one-off coordinator which will shut down right
// away. If we ended up here with an error, we'll always start
// the coordinator - the transaction has laid down intents, so
// we expect it to be committed/aborted at some point in the
// future.
if _, isEnding := ba.GetArg(roachpb.EndTransaction); err != nil || !isEnding {
trace.Event("coordinator spawns")
if !tc.stopper.RunAsyncTask(func() {
tc.heartbeatLoop(id)
}) {
// The system is already draining and we can't start the
// heartbeat. We refuse new transactions for now because
// they're likely not going to have all intents committed.
// In principle, we can relax this as needed though.
tc.unregisterTxnLocked(id)
return roachpb.NewError(&roachpb.NodeUnavailableError{})
}
}
}
for _, intent := range intents {
txnMeta.addKeyRange(intent.Key, intent.EndKey)
}
}
// Update our record of this transaction, even on error.
if txnMeta != nil {
txnMeta.txn = *newTxn
if !txnMeta.txn.Writing {
panic("tracking a non-writing txn")
}
txnMeta.setLastUpdate(tc.clock.PhysicalNow())
}
if err == nil {
// For successful transactional requests, always send the updated txn
// record back.
br.Txn = newTxn
}
return pErr
}()
}
// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(
startNS int64, ctx context.Context, ba roachpb.BatchRequest,
br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
newTxn := &roachpb.Transaction{}
newTxn.Update(ba.Txn)
if pErr == nil {
newTxn.Update(br.Txn)
} else {
newTxn.Update(pErr.GetTxn())
}
switch t := pErr.GetDetail().(type) {
case *roachpb.TransactionStatusError:
// Likely already committed or more obscure errors such as epoch or
// timestamp regressions; consider txn dead.
defer tc.cleanupTxn(ctx, *pErr.GetTxn())
case *roachpb.OpRequiresTxnError:
panic("OpRequiresTxnError must not happen at this level")
case *roachpb.ReadWithinUncertaintyIntervalError:
// If the reader encountered a newer write within the uncertainty
// interval, we advance the txn's timestamp just past the last observed
// timestamp from the node.
restartTS, ok := newTxn.GetObservedTimestamp(pErr.OriginNode)
if !ok {
pErr = roachpb.NewError(util.Errorf("no observed timestamp for node %d found on uncertainty restart", pErr.OriginNode))
} else {
newTxn.Timestamp.Forward(restartTS)
newTxn.Restart(ba.UserPriority, newTxn.Priority, newTxn.Timestamp)
}
case *roachpb.TransactionAbortedError:
// Increase timestamp if applicable.
newTxn.Timestamp.Forward(pErr.GetTxn().Timestamp)
newTxn.Priority = pErr.GetTxn().Priority
// Clean up the freshly aborted transaction in defer(), avoiding a
// race with the state update below.
defer tc.cleanupTxn(ctx, *newTxn)
case *roachpb.TransactionPushError:
// Increase timestamp if applicable, ensuring that we're
// just ahead of the pushee.
newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp)
newTxn.Restart(ba.UserPriority, t.PusheeTxn.Priority-1, newTxn.Timestamp)
case *roachpb.TransactionRetryError:
// Increase timestamp so on restart, we're ahead of any timestamp
// cache entries or newer versions which caused the restart.
newTxn.Restart(ba.UserPriority, pErr.GetTxn().Priority, newTxn.Timestamp)
case *roachpb.WriteTooOldError:
newTxn.Restart(ba.UserPriority, newTxn.Priority, t.ActualTimestamp)
case nil:
// Nothing to do here, avoid the default case.
default:
if pErr.GetTxn() != nil {
if pErr.CanRetry() {
panic("Retryable internal error must not happen at this level")
} else {
// Do not clean up the transaction here since the client might still
// want to continue the transaction. For example, a client might
// continue its transaction after receiving ConditionFailedError, which
// can come from a unique index violation.
}
}
}
if pErr != nil && pErr.GetTxn() != nil {
// Avoid changing existing errors because sometimes they escape into
// goroutines and then there are races. Fairly sure there isn't one
// here, but better safe than sorry.
pErrShallow := *pErr
pErrShallow.SetTxn(newTxn)
pErr = &pErrShallow
}
if newTxn.ID == nil {
return pErr
}
txnID := *newTxn.ID
tc.Lock()
defer tc.Unlock()
txnMeta := tc.txns[txnID]
// For successful transactional requests, keep the written intents and
// the updated transaction record to be sent along with the reply.
// The transaction metadata is created with the first writing operation.
// A tricky edge case is that of a transaction which "fails" on the
// first writing request, but actually manages to write some intents
// (for example, due to being multi-range). In this case, there will
// be an error, but the transaction will be marked as Writing and the
// coordinator must track the state, for the client's retry will be
// performed with a Writing transaction which the coordinator rejects
// unless it is tracking it (on top of it making sense to track it;
// after all, it **has** laid down intents and only the coordinator
// can augment a potential EndTransaction call). See #3303.
var intentGroup interval.RangeGroup
if txnMeta != nil {
intentGroup = txnMeta.keys
} else if pErr == nil || newTxn.Writing {
intentGroup = interval.NewRangeTree()
}
if intentGroup != nil {
// Adding the intents even on error reduces the likelihood of dangling
// intents blocking concurrent writers for extended periods of time.
// See #3346.
ba.IntentSpanIterate(func(key, endKey roachpb.Key) {
addKeyRange(intentGroup, key, endKey)
})
if txnMeta == nil && intentGroup.Len() > 0 {
if !newTxn.Writing {
panic("txn with intents marked as non-writing")
}
// If the transaction is already over, there's no point in
// launching a one-off coordinator which will shut down right
// away. If we ended up here with an error, we'll always start
// the coordinator - the transaction has laid down intents, so
// we expect it to be committed/aborted at some point in the
// future.
if _, isEnding := ba.GetArg(roachpb.EndTransaction); pErr != nil || !isEnding {
log.Trace(ctx, "coordinator spawns")
txnMeta = &txnMetadata{
txn: *newTxn,
keys: intentGroup,
firstUpdateNanos: startNS,
lastUpdateNanos: tc.clock.PhysicalNow(),
timeoutDuration: tc.clientTimeout,
txnEnd: make(chan struct{}),
}
tc.txns[txnID] = txnMeta
if !tc.stopper.RunAsyncTask(func() {
tc.heartbeatLoop(ctx, txnID)
}) {
// The system is already draining and we can't start the
// heartbeat. We refuse new transactions for now because
// they're likely not going to have all intents committed.
// In principle, we can relax this as needed though.
tc.unregisterTxnLocked(txnID)
return roachpb.NewError(&roachpb.NodeUnavailableError{})
}
} else {
// If this was a successful one phase commit, update stats
// directly as they won't otherwise be updated on heartbeat
// loop shutdown.
etArgs, ok := br.Responses[len(br.Responses)-1].GetInner().(*roachpb.EndTransactionResponse)
tc.updateStats(tc.clock.PhysicalNow()-startNS, 0, newTxn.Status, ok && etArgs.OnePhaseCommit)
}
}
}
// Update our record of this transaction, even on error.
if txnMeta != nil {
txnMeta.txn = *newTxn
if !txnMeta.txn.Writing {
panic("tracking a non-writing txn")
}
txnMeta.setLastUpdate(tc.clock.PhysicalNow())
}
if pErr == nil {
// For successful transactional requests, always send the updated txn
// record back.
br.Txn = newTxn
}
return pErr
}
// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba roachpb.BatchRequest, br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
trace := tracer.FromCtx(ctx)
newTxn := &roachpb.Transaction{}
newTxn.Update(ba.GetTxn())
err := pErr.GoError()
switch t := err.(type) {
case nil:
newTxn.Update(br.GetTxn())
// Move txn timestamp forward to response timestamp if applicable.
// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
// Looks like this isn't necessary any more, nor did it prevent a bug
// referenced in a TODO there.
newTxn.Timestamp.Forward(br.Timestamp)
case *roachpb.TransactionStatusError:
// Likely already committed or more obscure errors such as epoch or
// timestamp regressions; consider txn dead.
defer tc.cleanupTxn(trace, t.Txn)
case *roachpb.OpRequiresTxnError:
// TODO(tschottdorf): range-spanning autowrap currently broken.
panic("TODO(tschottdorf): disabled")
case *roachpb.ReadWithinUncertaintyIntervalError:
// Mark the host as certain. See the protobuf comment for
// Transaction.CertainNodes for details.
if t.NodeID == 0 {
panic("no replica set in header on uncertainty restart")
}
newTxn.CertainNodes.Add(t.NodeID)
// If the reader encountered a newer write within the uncertainty
// interval, move the timestamp forward, just past that write or
// up to MaxTimestamp, whichever comes first.
candidateTS := newTxn.MaxTimestamp
candidateTS.Backward(t.ExistingTimestamp.Add(0, 1))
newTxn.Timestamp.Forward(candidateTS)
newTxn.Restart(ba.GetUserPriority(), newTxn.Priority, newTxn.Timestamp)
t.Txn = *newTxn
case *roachpb.TransactionAbortedError:
// Increase timestamp if applicable.
newTxn.Timestamp.Forward(t.Txn.Timestamp)
newTxn.Priority = t.Txn.Priority
t.Txn = *newTxn
// Clean up the freshly aborted transaction in defer(), avoiding a
// race with the state update below.
defer tc.cleanupTxn(trace, t.Txn)
case *roachpb.TransactionPushError:
// Increase timestamp if applicable, ensuring that we're
// just ahead of the pushee.
newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
newTxn.Restart(ba.GetUserPriority(), t.PusheeTxn.Priority-1, newTxn.Timestamp)
t.Txn = newTxn
case *roachpb.TransactionRetryError:
// Increase timestamp if applicable.
newTxn.Timestamp.Forward(t.Txn.Timestamp)
newTxn.Restart(ba.GetUserPriority(), t.Txn.Priority, newTxn.Timestamp)
t.Txn = *newTxn
case roachpb.TransactionRestartError:
// Assertion: The above cases should exhaust all ErrorDetails which
// carry a Transaction.
if pErr.Detail != nil {
panic(fmt.Sprintf("unhandled TransactionRestartError %T", err))
}
}
return func() *roachpb.Error {
if len(newTxn.ID) <= 0 {
return pErr
}
id := string(newTxn.ID)
tc.Lock()
defer tc.Unlock()
txnMeta := tc.txns[id]
// For successful transactional requests, keep the written intents and
// the updated transaction record to be sent along with the reply.
// The transaction metadata is created with the first writing operation
// TODO(tschottdorf): already computed the intents prior to sending,
// consider re-using those.
if intents := ba.GetIntents(); len(intents) > 0 && err == nil {
if txnMeta == nil {
newTxn.Writing = true
txnMeta = &txnMetadata{
txn: *newTxn,
keys: cache.NewIntervalCache(cache.Config{Policy: cache.CacheNone}),
firstUpdateNanos: tc.clock.PhysicalNow(),
lastUpdateNanos: tc.clock.PhysicalNow(),
timeoutDuration: tc.clientTimeout,
txnEnd: make(chan struct{}),
}
tc.txns[id] = txnMeta
// If the transaction is already over, there's no point in
// launching a one-off coordinator which will shut down right
// away.
if _, isEnding := ba.GetArg(roachpb.EndTransaction); !isEnding {
trace.Event("coordinator spawns")
if !tc.stopper.RunAsyncTask(func() {
tc.heartbeatLoop(id)
}) {
// The system is already draining and we can't start the
// heartbeat. We refuse new transactions for now because
// they're likely not going to have all intents committed.
// In principle, we can relax this as needed though.
tc.unregisterTxnLocked(id)
return roachpb.NewError(&roachpb.NodeUnavailableError{})
}
}
}
for _, intent := range intents {
txnMeta.addKeyRange(intent.Key, intent.EndKey)
}
}
// Update our record of this transaction, even on error.
if txnMeta != nil {
txnMeta.txn.Update(newTxn) // better to replace after #2300
if !txnMeta.txn.Writing {
panic("tracking a non-writing txn")
}
txnMeta.setLastUpdate(tc.clock.PhysicalNow())
}
if err == nil {
// For successful transactional requests, always send the updated txn
// record back.
if br.Txn == nil {
br.Txn = &roachpb.Transaction{}
}
*br.Txn = *newTxn
}
return pErr
}()
}
// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba roachpb.BatchRequest, br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
sp, cleanupSp := tracing.SpanFromContext(opTxnCoordSender, tc.tracer, ctx)
defer cleanupSp()
newTxn := &roachpb.Transaction{}
newTxn.Update(ba.Txn)
if pErr == nil {
newTxn.Update(br.Txn)
} else {
newTxn.Update(pErr.GetTxn())
}
// If the request was successful but we're in a transaction which needs to
// restart but doesn't know it yet, let it restart now (as opposed to
// waiting until EndTransaction).
if pErr == nil && newTxn.Isolation == roachpb.SERIALIZABLE &&
!newTxn.OrigTimestamp.Equal(newTxn.Timestamp) {
pErr = roachpb.NewErrorWithTxn(roachpb.NewTransactionRetryError(), br.Txn)
br = nil
}
switch t := pErr.GetDetail().(type) {
case nil:
// Move txn timestamp forward to response timestamp if applicable.
// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
// Looks like this isn't necessary any more, nor did it prevent a bug
// referenced in a TODO there.
newTxn.Timestamp.Forward(br.Timestamp)
case *roachpb.TransactionStatusError:
// Likely already committed or more obscure errors such as epoch or
// timestamp regressions; consider txn dead.
defer tc.cleanupTxn(sp, *pErr.GetTxn())
case *roachpb.OpRequiresTxnError:
panic("OpRequiresTxnError must not happen at this level")
case *roachpb.ReadWithinUncertaintyIntervalError:
// If the reader encountered a newer write within the uncertainty
// interval, we advance the txn's timestamp just past the last observed
// timestamp from the node.
restartTS, ok := newTxn.GetObservedTimestamp(pErr.OriginNode)
if !ok {
pErr = roachpb.NewError(util.Errorf("no observed timestamp for node %d found on uncertainty restart", pErr.OriginNode))
} else {
newTxn.Timestamp.Forward(restartTS)
newTxn.Restart(ba.UserPriority, newTxn.Priority, newTxn.Timestamp)
}
case *roachpb.TransactionAbortedError:
// Increase timestamp if applicable.
newTxn.Timestamp.Forward(pErr.GetTxn().Timestamp)
newTxn.Priority = pErr.GetTxn().Priority
// Clean up the freshly aborted transaction in defer(), avoiding a
// race with the state update below.
defer tc.cleanupTxn(sp, *newTxn)
case *roachpb.TransactionPushError:
// Increase timestamp if applicable, ensuring that we're
// just ahead of the pushee.
newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
newTxn.Restart(ba.UserPriority, t.PusheeTxn.Priority-1, newTxn.Timestamp)
case *roachpb.TransactionRetryError:
newTxn.Restart(ba.UserPriority, pErr.GetTxn().Priority, newTxn.Timestamp)
default:
if pErr.GetTxn() != nil {
if pErr.CanRetry() {
panic("Retryable internal error must not happen at this level")
} else {
// Do not clean up the transaction here since the client might still
// want to continue the transaction. For example, a client might
// continue its transaction after receiving ConditionFailedError, which
// can come from a unique index violation.
}
}
}
if pErr != nil && pErr.GetTxn() != nil {
// Avoid changing existing errors because sometimes they escape into
// goroutines and then there are races. Fairly sure there isn't one
// here, but better safe than sorry.
pErrShallow := *pErr
pErrShallow.SetTxn(newTxn)
pErr = &pErrShallow
}
if newTxn.ID == nil {
return pErr
}
txnID := *newTxn.ID
tc.Lock()
defer tc.Unlock()
txnMeta := tc.txns[txnID]
// For successful transactional requests, keep the written intents and
// the updated transaction record to be sent along with the reply.
// The transaction metadata is created with the first writing operation.
// A tricky edge case is that of a transaction which "fails" on the
// first writing request, but actually manages to write some intents
// (for example, due to being multi-range). In this case, there will
// be an error, but the transaction will be marked as Writing and the
// coordinator must track the state, for the client's retry will be
// performed with a Writing transaction which the coordinator rejects
// unless it is tracking it (on top of it making sense to track it;
// after all, it **has** laid down intents and only the coordinator
// can augment a potential EndTransaction call). See #3303.
intents := ba.GetIntentSpans()
if len(intents) > 0 && (pErr == nil || newTxn.Writing) {
if txnMeta == nil {
if !newTxn.Writing {
panic("txn with intents marked as non-writing")
}
// If the transaction is already over, there's no point in
// launching a one-off coordinator which will shut down right
// away. If we ended up here with an error, we'll always start
// the coordinator - the transaction has laid down intents, so
// we expect it to be committed/aborted at some point in the
// future.
if _, isEnding := ba.GetArg(roachpb.EndTransaction); pErr != nil || !isEnding {
sp.LogEvent("coordinator spawns")
txnMeta = &txnMetadata{
txn: *newTxn,
keys: cache.NewIntervalCache(cache.Config{Policy: cache.CacheNone}),
firstUpdateNanos: tc.clock.PhysicalNow(),
lastUpdateNanos: tc.clock.PhysicalNow(),
timeoutDuration: tc.clientTimeout,
txnEnd: make(chan struct{}),
}
tc.txns[txnID] = txnMeta
if !tc.stopper.RunAsyncTask(func() {
tc.heartbeatLoop(txnID)
}) {
// The system is already draining and we can't start the
// heartbeat. We refuse new transactions for now because
// they're likely not going to have all intents committed.
// In principle, we can relax this as needed though.
tc.unregisterTxnLocked(txnID)
return roachpb.NewError(&roachpb.NodeUnavailableError{})
}
}
}
}
// Update our record of this transaction, even on error.
if txnMeta != nil {
txnMeta.txn = *newTxn
if !txnMeta.txn.Writing {
panic("tracking a non-writing txn")
}
txnMeta.setLastUpdate(tc.clock.PhysicalNow())
// Adding the intents even on error reduces the likelihood of dangling
// intents blocking concurrent writers for extended periods of time.
// See #3346.
for _, intent := range intents {
txnMeta.addKeyRange(intent.Key, intent.EndKey)
}
}
if pErr == nil {
// For successful transactional requests, always send the updated txn
// record back.
br.Txn = newTxn
}
return pErr
}
