// processReplica processes a single replica. This should not be
// called externally to the queue. bq.mu.Lock should not be held
// while calling this method.
func (bq *baseQueue) processReplica(repl *Replica, clock *hlc.Clock) error {
bq.processMu.Lock()
defer bq.processMu.Unlock()
// Load the system config.
cfg, ok := bq.gossip.GetSystemConfig()
if !ok {
log.VEventf(1, bq.ctx, "no system config available. skipping")
return nil
}
if bq.requiresSplit(cfg, repl) {
// Range needs to be split due to zone configs, but queue does
// not accept unsplit ranges.
log.VEventf(3, bq.ctx, "%s: split needed; skipping", repl)
return nil
}
sp := repl.store.Tracer().StartSpan(bq.name)
ctx := opentracing.ContextWithSpan(context.Background(), sp)
defer sp.Finish()
log.Tracef(ctx, "processing replica %s", repl)
// If the queue requires a replica to have the range lease in
// order to be processed, check whether this replica has range lease
// and renew or acquire if necessary.
if bq.needsLease {
// Create a "fake" get request in order to invoke redirectOnOrAcquireLease.
if err := repl.redirectOnOrAcquireLease(ctx); err != nil {
if _, harmless := err.GetDetail().(*roachpb.NotLeaseHolderError); harmless {
log.VEventf(3, bq.ctx, "%s: not holding lease; skipping", repl)
return nil
}
return errors.Wrapf(err.GoError(), "%s: could not obtain lease", repl)
}
log.Trace(ctx, "got range lease")
}
log.VEventf(3, bq.ctx, "%s: processing", repl)
start := timeutil.Now()
if err := bq.impl.process(ctx, clock.Now(), repl, cfg); err != nil {
return err
}
log.VEventf(2, bq.ctx, "%s: done: %s", repl, timeutil.Since(start))
log.Trace(ctx, "done")
return nil
}
// InitSenderForLocalTestCluster initializes a TxnCoordSender that can be used
// with LocalTestCluster.
func InitSenderForLocalTestCluster(
nodeDesc *roachpb.NodeDescriptor,
tracer opentracing.Tracer,
clock *hlc.Clock,
latency time.Duration,
stores client.Sender,
stopper *stop.Stopper,
gossip *gossip.Gossip,
) client.Sender {
var rpcSend rpcSendFn = func(_ SendOptions, _ ReplicaSlice,
args roachpb.BatchRequest, _ *rpc.Context) (*roachpb.BatchResponse, error) {
if latency > 0 {
time.Sleep(latency)
}
sp := tracer.StartSpan("node")
defer sp.Finish()
ctx := opentracing.ContextWithSpan(context.Background(), sp)
log.Trace(ctx, args.String())
br, pErr := stores.Send(ctx, args)
if br == nil {
br = &roachpb.BatchResponse{}
}
if br.Error != nil {
panic(roachpb.ErrorUnexpectedlySet(stores, br))
}
br.Error = pErr
if pErr != nil {
log.Trace(ctx, "error: "+pErr.String())
}
return br, nil
}
retryOpts := GetDefaultDistSenderRetryOptions()
retryOpts.Closer = stopper.ShouldDrain()
distSender := NewDistSender(&DistSenderContext{
Clock: clock,
RangeDescriptorCacheSize: defaultRangeDescriptorCacheSize,
RangeLookupMaxRanges: defaultRangeLookupMaxRanges,
LeaderCacheSize: defaultLeaderCacheSize,
RPCRetryOptions: &retryOpts,
nodeDescriptor: nodeDesc,
RPCSend: rpcSend, // defined above
RangeDescriptorDB: stores.(RangeDescriptorDB), // for descriptor lookup
}, gossip)
return NewTxnCoordSender(distSender, clock, false /* !linearizable */, tracer,
stopper, NewTxnMetrics(metric.NewRegistry()))
}
// processReplica processes a single replica. This should not be
// called externally to the queue. bq.mu.Lock should not be held
// while calling this method.
func (bq *baseQueue) processReplica(repl *Replica, clock *hlc.Clock) error {
// Load the system config.
cfg, ok := bq.gossip.GetSystemConfig()
if !ok {
bq.eventLog.VInfof(log.V(1), "no system config available. skipping")
return nil
}
desc := repl.Desc()
if !bq.acceptsUnsplitRanges && cfg.NeedsSplit(desc.StartKey, desc.EndKey) {
// Range needs to be split due to zone configs, but queue does
// not accept unsplit ranges.
bq.eventLog.VInfof(log.V(3), "%s: split needed; skipping", repl)
return nil
}
sp := repl.store.Tracer().StartSpan(bq.name)
ctx := opentracing.ContextWithSpan(repl.context(context.Background()), sp)
log.Trace(ctx, fmt.Sprintf("queue start for range %d", repl.RangeID))
defer sp.Finish()
// If the queue requires a replica to have the range leader lease in
// order to be processed, check whether this replica has leader lease
// and renew or acquire if necessary.
if bq.needsLeaderLease {
// Create a "fake" get request in order to invoke redirectOnOrAcquireLease.
if err := repl.redirectOnOrAcquireLeaderLease(ctx); err != nil {
if _, harmless := err.GetDetail().(*roachpb.NotLeaderError); harmless {
bq.eventLog.VInfof(log.V(3), "%s: not holding lease; skipping", repl)
return nil
}
return errors.Wrapf(err.GoError(), "%s: could not obtain lease", repl)
}
log.Trace(ctx, "got range lease")
}
bq.eventLog.VInfof(log.V(3), "%s: processing", repl)
start := timeutil.Now()
if err := bq.impl.process(ctx, clock.Now(), repl, cfg); err != nil {
return err
}
bq.eventLog.VInfof(log.V(2), "%s: done: %s", repl, timeutil.Since(start))
log.Trace(ctx, "done")
return nil
}
// EvictAndReplace instructs the evictionToken to evict the RangeDescriptor it was
// created with from the rangeDescriptorCache. It also allows the user to provide
// new RangeDescriptors to insert into the cache, all atomically. When called without
// arguments, EvictAndReplace will behave the same as Evict.
func (et *evictionToken) EvictAndReplace(ctx context.Context, newDescs ...roachpb.RangeDescriptor) error {
var err error
et.doOnce.Do(func() {
et.doLocker.Lock()
defer et.doLocker.Unlock()
err = et.do()
if err == nil {
if len(newDescs) > 0 {
err = et.doReplace(newDescs...)
log.Trace(ctx, fmt.Sprintf("evicting cached range descriptor with %d replacements",
len(newDescs)))
} else {
log.Trace(ctx, "evicting cached range descriptor")
}
}
})
return err
}
// process synchronously invokes admin split for each proposed split key.
func (sq *splitQueue) process(
ctx context.Context,
now hlc.Timestamp,
rng *Replica,
sysCfg config.SystemConfig,
) error {
// First handle case of splitting due to zone config maps.
desc := rng.Desc()
splitKeys := sysCfg.ComputeSplitKeys(desc.StartKey, desc.EndKey)
if len(splitKeys) > 0 {
log.Infof("splitting %s at keys %v", rng, splitKeys)
log.Trace(ctx, fmt.Sprintf("splitting at keys %v", splitKeys))
for _, splitKey := range splitKeys {
if err := sq.db.AdminSplit(splitKey.AsRawKey()); err != nil {
return errors.Errorf("unable to split %s at key %q: %s", rng, splitKey, err)
}
}
return nil
}
// Next handle case of splitting due to size.
zone, err := sysCfg.GetZoneConfigForKey(desc.StartKey)
if err != nil {
return err
}
size := rng.GetMVCCStats().Total()
// FIXME: why is this implementation not the same as the one above?
if float64(size)/float64(zone.RangeMaxBytes) > 1 {
log.Infof("splitting %s size=%d max=%d", rng, size, zone.RangeMaxBytes)
log.Trace(ctx, fmt.Sprintf("splitting size=%d max=%d", size, zone.RangeMaxBytes))
if _, pErr := client.SendWrappedWith(rng, ctx, roachpb.Header{
Timestamp: now,
}, &roachpb.AdminSplitRequest{
Span: roachpb.Span{Key: desc.StartKey.AsRawKey()},
}); pErr != nil {
return pErr.GoError()
}
}
return nil
}
// Send implements the client.Sender interface. The store is looked up from the
// store map if specified by the request; otherwise, the command is being
// executed locally, and the replica is determined via lookup through each
// store's LookupRange method. The latter path is taken only by unit tests.
func (ls *Stores) Send(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
// If we aren't given a Replica, then a little bending over
// backwards here. This case applies exclusively to unittests.
if ba.RangeID == 0 || ba.Replica.StoreID == 0 {
rs, err := keys.Range(ba)
if err != nil {
return nil, roachpb.NewError(err)
}
rangeID, repl, err := ls.lookupReplica(rs.Key, rs.EndKey)
if err != nil {
return nil, roachpb.NewError(err)
}
ba.RangeID = rangeID
ba.Replica = *repl
}
ctx = log.Add(ctx,
log.RangeID, ba.RangeID)
store, err := ls.GetStore(ba.Replica.StoreID)
if err != nil {
return nil, roachpb.NewError(err)
}
if ba.Txn != nil {
// For calls that read data within a txn, we keep track of timestamps
// observed from the various participating nodes' HLC clocks. If we have
// a timestamp on file for this Node which is smaller than MaxTimestamp,
// we can lower MaxTimestamp accordingly. If MaxTimestamp drops below
// OrigTimestamp, we effectively can't see uncertainty restarts any
// more.
// Note that it's not an issue if MaxTimestamp propagates back out to
// the client via a returned Transaction update - when updating a Txn
// from another, the larger MaxTimestamp wins.
if maxTS, ok := ba.Txn.GetObservedTimestamp(ba.Replica.NodeID); ok && maxTS.Less(ba.Txn.MaxTimestamp) {
// Copy-on-write to protect others we might be sharing the Txn with.
shallowTxn := *ba.Txn
// The uncertainty window is [OrigTimestamp, maxTS), so if that window
// is empty, there won't be any uncertainty restarts.
if !ba.Txn.OrigTimestamp.Less(maxTS) {
log.Trace(ctx, "read has no clock uncertainty")
}
shallowTxn.MaxTimestamp.Backward(maxTS)
ba.Txn = &shallowTxn
}
}
br, pErr := store.Send(ctx, ba)
if br != nil && br.Error != nil {
panic(roachpb.ErrorUnexpectedlySet(store, br))
}
return br, pErr
}
func (s *senderTransport) SendNext(done chan BatchCall) {
if s.called {
panic("called an exhausted transport")
}
s.called = true
sp := s.tracer.StartSpan("node")
defer sp.Finish()
ctx := opentracing.ContextWithSpan(context.Background(), sp)
log.Trace(ctx, s.args.String())
br, pErr := s.sender.Send(ctx, s.args)
if br == nil {
br = &roachpb.BatchResponse{}
}
if br.Error != nil {
panic(roachpb.ErrorUnexpectedlySet(s.sender, br))
}
br.Error = pErr
if pErr != nil {
log.Trace(ctx, "error: "+pErr.String())
}
done <- BatchCall{Reply: br}
}
// cleanupTxnLocked is called when a transaction ends. The transaction record
// is updated and the heartbeat goroutine signaled to clean up the transaction
// gracefully.
func (tc *TxnCoordSender) cleanupTxnLocked(ctx context.Context, txn roachpb.Transaction) {
log.Trace(ctx, "coordinator stops")
txnMeta, ok := tc.txns[*txn.ID]
// The heartbeat might've already removed the record. Or we may have already
// closed txnEnd but we are racing with the heartbeat cleanup.
if !ok || txnMeta.txnEnd == nil {
return
}
// The supplied txn may be newer than the one in txnMeta, which is relevant
// for stats.
txnMeta.txn = txn
// Trigger heartbeat shutdown.
close(txnMeta.txnEnd)
txnMeta.txnEnd = nil
}
// cleanupTxn is called when a transaction ends. The transaction record is
// updated and the heartbeat goroutine signaled to clean up the transaction
// gracefully.
func (tc *TxnCoordSender) cleanupTxn(ctx context.Context, txn roachpb.Transaction) {
log.Trace(ctx, "coordinator stops")
tc.Lock()
defer tc.Unlock()
txnMeta, ok := tc.txns[*txn.ID]
// The heartbeat might've already removed the record.
if !ok {
return
}
// The supplied txn may be newer than the one in txnMeta, which is relevant
// for stats.
txnMeta.txn = txn
// Trigger heartbeat shutdown.
close(txnMeta.txnEnd)
txnMeta.txnEnd = nil
}
func (tc *TxnCoordSender) heartbeat(ctx context.Context, txnID uuid.UUID) bool {
tc.Lock()
txnMeta := tc.txns[txnID]
txn := txnMeta.txn.Clone()
tc.Unlock()
// Before we send a heartbeat, determine whether this transaction should be
// considered abandoned. If so, exit heartbeat. If ctx.Done() is not nil, then
// it is a cancellable Context and we skip this check and use the ctx lifetime
// instead of a timeout.
if ctx.Done() == nil && txnMeta.hasClientAbandonedCoord(tc.clock.PhysicalNow()) {
tc.clientHasAbandoned(txnID)
return false
}
ba := roachpb.BatchRequest{}
ba.Txn = &txn
hb := &roachpb.HeartbeatTxnRequest{
Now: tc.clock.Now(),
}
hb.Key = txn.Key
ba.Add(hb)
log.Trace(ctx, "heartbeat")
_, err := tc.wrapped.Send(ctx, ba)
// If the transaction is not in pending state, then we can stop
// the heartbeat. It's either aborted or committed, and we resolve
// write intents accordingly.
if err != nil {
log.Warningf("heartbeat to %s failed: %s", txn, err)
}
// TODO(bdarnell): once we have gotten a heartbeat response with
// Status != PENDING, future heartbeats are useless. However, we
// need to continue the heartbeatLoop until the client either
// commits or abandons the transaction. We could save a little
// pointless work by restructuring this loop to stop sending
// heartbeats between the time that the transaction is aborted and
// the client finds out. Furthermore, we could use this information
// to send TransactionAbortedErrors to the client so it can restart
// immediately instead of running until its EndTransaction.
return true
}
// sendSingleRange gathers and rearranges the replicas, and makes an RPC call.
func (ds *DistSender) sendSingleRange(
ctx context.Context, ba roachpb.BatchRequest, desc *roachpb.RangeDescriptor,
) (*roachpb.BatchResponse, *roachpb.Error) {
log.Trace(ctx, fmt.Sprintf("sending RPC to [%s, %s)", desc.StartKey, desc.EndKey))
// Try to send the call.
replicas := newReplicaSlice(ds.gossip, desc)
// Rearrange the replicas so that those replicas with long common
// prefix of attributes end up first. If there's no prefix, this is a
// no-op.
order := ds.optimizeReplicaOrder(replicas)
// If this request needs to go to a leader and we know who that is, move
// it to the front.
if !(ba.IsReadOnly() && ba.ReadConsistency == roachpb.INCONSISTENT) {
if leader := ds.leaderCache.Lookup(roachpb.RangeID(desc.RangeID)); leader.StoreID > 0 {
if i := replicas.FindReplica(leader.StoreID); i >= 0 {
replicas.MoveToFront(i)
order = orderStable
}
}
}
// TODO(tschottdorf): should serialize the trace here, not higher up.
br, pErr := ds.sendRPC(ctx, desc.RangeID, replicas, order, ba)
if pErr != nil {
return nil, pErr
}
// If the reply contains a timestamp, update the local HLC with it.
if br.Error != nil && br.Error.Now != roachpb.ZeroTimestamp {
ds.clock.Update(br.Error.Now)
} else if br.Now != roachpb.ZeroTimestamp {
ds.clock.Update(br.Now)
}
// Untangle the error from the received response.
pErr = br.Error
br.Error = nil // scrub the response error
return br, pErr
}
// Send implements the batch.Sender interface. If the request is part of a
// transaction, the TxnCoordSender adds the transaction to a map of active
// transactions and begins heartbeating it. Every subsequent request for the
// same transaction updates the lastUpdate timestamp to prevent live
// transactions from being considered abandoned and garbage collected.
// Read/write mutating requests have their key or key range added to the
// transaction's interval tree of key ranges for eventual cleanup via resolved
// write intents; they're tagged to an outgoing EndTransaction request, with
// the receiving replica in charge of resolving them.
func (tc *TxnCoordSender) Send(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
{
// Start new or pick up active trace and embed its trace metadata into
// header for use by RPC recipients. From here on, there's always an active
// Trace, though its overhead is small unless it's sampled.
sp := opentracing.SpanFromContext(ctx)
if sp == nil {
sp = tc.tracer.StartSpan(opTxnCoordSender)
defer sp.Finish()
ctx = opentracing.ContextWithSpan(ctx, sp)
}
// TODO(tschottdorf): To get rid of the spurious alloc below we need to
// implement the carrier interface on ba.Header or make Span non-nullable,
// both of which force all of ba on the Heap. It's already there, so may
// not be a big deal, but ba should live on the stack. Also not easy to use
// a buffer pool here since anything that goes into the RPC layer could be
// used by goroutines we didn't wait for.
if ba.Header.Trace == nil {
ba.Header.Trace = &tracing.Span{}
}
if err := tc.tracer.Inject(sp, basictracer.Delegator, ba.Trace); err != nil {
return nil, roachpb.NewError(err)
}
}
startNS := tc.clock.PhysicalNow()
if ba.Txn != nil {
// If this request is part of a transaction...
if err := tc.maybeBeginTxn(&ba); err != nil {
return nil, roachpb.NewError(err)
}
txnID := *ba.Txn.ID
// Verify that if this Transaction is not read-only, we have it on file.
// If not, refuse further operations - the transaction was aborted due
// to a timeout or the client must have issued a write on another
// coordinator previously.
if ba.Txn.Writing {
tc.Lock()
_, ok := tc.txns[txnID]
tc.Unlock()
if !ok {
pErr := roachpb.NewErrorf("writing transaction timed out, was aborted, " +
"or ran on multiple coordinators")
return nil, pErr
}
}
if rArgs, ok := ba.GetArg(roachpb.EndTransaction); ok {
et := rArgs.(*roachpb.EndTransactionRequest)
if len(et.Key) != 0 {
return nil, roachpb.NewErrorf("EndTransaction must not have a Key set")
}
et.Key = ba.Txn.Key
if len(et.IntentSpans) > 0 {
// TODO(tschottdorf): it may be useful to allow this later.
// That would be part of a possible plan to allow txns which
// write on multiple coordinators.
return nil, roachpb.NewErrorf("client must not pass intents to EndTransaction")
}
tc.Lock()
txnMeta, metaOK := tc.txns[txnID]
{
// Populate et.IntentSpans, taking into account both existing
// writes (if any) and new writes in this batch, and taking
// care to perform proper deduplication.
var keys interval.RangeGroup
if metaOK {
keys = txnMeta.keys
} else {
keys = interval.NewRangeTree()
}
ba.IntentSpanIterate(func(key, endKey roachpb.Key) {
addKeyRange(keys, key, endKey)
})
et.IntentSpans = collectIntentSpans(keys)
}
tc.Unlock()
if len(et.IntentSpans) > 0 {
// All good, proceed.
} else if !metaOK {
// If we don't have the transaction, then this must be a retry
// by the client. We can no longer reconstruct a correct
// request so we must fail.
//
// TODO(bdarnell): if we had a GetTransactionStatus API then
// we could lookup the transaction and return either nil or
// TransactionAbortedError instead of this ambivalent error.
return nil, roachpb.NewErrorf("transaction is already committed or aborted")
}
if len(et.IntentSpans) == 0 {
// If there aren't any intents, then there's factually no
// transaction to end. Read-only txns have all of their state in
// the client.
return nil, roachpb.NewErrorf("cannot commit a read-only transaction")
}
if log.V(1) {
for _, intent := range et.IntentSpans {
log.Trace(ctx, fmt.Sprintf("intent: [%s,%s)", intent.Key, intent.EndKey))
}
}
}
}
// Send the command through wrapped sender, taking appropriate measures
// on error.
var br *roachpb.BatchResponse
{
var pErr *roachpb.Error
br, pErr = tc.wrapped.Send(ctx, ba)
if _, ok := pErr.GetDetail().(*roachpb.OpRequiresTxnError); ok {
// TODO(tschottdorf): needs to keep the trace.
br, pErr = tc.resendWithTxn(ba)
}
if pErr = tc.updateState(startNS, ctx, ba, br, pErr); pErr != nil {
log.Trace(ctx, fmt.Sprintf("error: %s", pErr))
return nil, pErr
}
}
if br.Txn == nil {
return br, nil
}
if _, ok := ba.GetArg(roachpb.EndTransaction); !ok {
return br, nil
}
// If the --linearizable flag is set, we want to make sure that
// all the clocks in the system are past the commit timestamp
// of the transaction. This is guaranteed if either
// - the commit timestamp is MaxOffset behind startNS
// - MaxOffset ns were spent in this function
// when returning to the client. Below we choose the option
// that involves less waiting, which is likely the first one
// unless a transaction commits with an odd timestamp.
if tsNS := br.Txn.Timestamp.WallTime; startNS > tsNS {
startNS = tsNS
}
sleepNS := tc.clock.MaxOffset() -
time.Duration(tc.clock.PhysicalNow()-startNS)
if tc.linearizable && sleepNS > 0 {
defer func() {
if log.V(1) {
log.Infof("%v: waiting %s on EndTransaction for linearizability", br.Txn.ID.Short(), util.TruncateDuration(sleepNS, time.Millisecond))
}
time.Sleep(sleepNS)
}()
}
if br.Txn.Status != roachpb.PENDING {
tc.cleanupTxn(ctx, *br.Txn)
}
return br, nil
}
func (tc *TxnCoordSender) heartbeat(ctx context.Context, txnID uuid.UUID) bool {
tc.Lock()
txnMeta := tc.txns[txnID]
txn := txnMeta.txn.Clone()
hasAbandoned := txnMeta.hasClientAbandonedCoord(tc.clock.PhysicalNow())
tc.Unlock()
if txn.Status != roachpb.PENDING {
// A previous iteration has already determined that the transaction is
// already finalized, so we wait for the client to realize that and
// want to keep our state for the time being (to dish out the right
// error once it returns).
return true
}
// Before we send a heartbeat, determine whether this transaction should be
// considered abandoned. If so, exit heartbeat. If ctx.Done() is not nil, then
// it is a cancellable Context and we skip this check and use the ctx lifetime
// instead of a timeout.
if ctx.Done() == nil && hasAbandoned {
if log.V(1) {
log.Infof(ctx, "transaction %s abandoned; stopping heartbeat", txnMeta.txn)
}
tc.tryAsyncAbort(txnID)
return false
}
ba := roachpb.BatchRequest{}
ba.Txn = &txn
hb := &roachpb.HeartbeatTxnRequest{
Now: tc.clock.Now(),
}
hb.Key = txn.Key
ba.Add(hb)
log.Trace(ctx, "heartbeat")
br, pErr := tc.wrapped.Send(ctx, ba)
// Correctness mandates that when we can't heartbeat the transaction, we
// make sure the client doesn't keep going. This is particularly relevant
// in the case of an ABORTED transaction, but if we can't reach the
// transaction record at all, we're going to have to assume we're aborted
// as well.
if pErr != nil {
log.Warningf(ctx, "heartbeat to %s failed: %s", txn, pErr)
// We're not going to let the client carry out additional requests, so
// try to clean up.
tc.tryAsyncAbort(*txn.ID)
txn.Status = roachpb.ABORTED
} else {
txn.Update(br.Responses[0].GetInner().(*roachpb.HeartbeatTxnResponse).Txn)
}
// Give the news to the txn in the txns map. This will update long-running
// transactions (which may find out that they have to restart in that way),
// but in particular makes sure that they notice when they've been aborted
// (in which case we'll give them an error on their next request).
tc.Lock()
tc.txns[txnID].txn.Update(&txn)
tc.Unlock()
return true
}
// maybePushTransactions tries to push the conflicting transaction(s)
// responsible for the given intents: either move its
// timestamp forward on a read/write conflict, abort it on a
// write/write conflict, or do nothing if the transaction is no longer
// pending.
//
// Returns a slice of intents which can now be resolved, and an error.
// The returned intents should be resolved via intentResolver.resolveIntents.
//
// If skipIfInFlight is true, then no PushTxns will be sent and no
// intents will be returned for any transaction for which there is
// another push in progress. This should only be used by callers who
// are not relying on the side effect of a push (i.e. only
// pushType==PUSH_TOUCH), and who also don't need to synchronize with
// the resolution of those intents (e.g. asynchronous resolutions of
// intents skipped on inconsistent reads).
//
// Callers are involved with
// a) conflict resolution for commands being executed at the Store with the
// client waiting,
// b) resolving intents encountered during inconsistent operations, and
// c) resolving intents upon EndTransaction which are not local to the given
// range. This is the only path in which the transaction is going to be
// in non-pending state and doesn't require a push.
func (ir *intentResolver) maybePushTransactions(ctx context.Context, intents []roachpb.Intent,
h roachpb.Header, pushType roachpb.PushTxnType, skipIfInFlight bool) (
[]roachpb.Intent, *roachpb.Error) {
now := ir.store.Clock().Now()
partialPusherTxn := h.Txn
// If there's no pusher, we communicate a priority by sending an empty
// txn with only the priority set. This is official usage of PushTxn.
if partialPusherTxn == nil {
partialPusherTxn = &roachpb.Transaction{
TxnMeta: roachpb.TxnMeta{
Priority: roachpb.MakePriority(h.UserPriority),
},
}
}
log.Trace(ctx, "intent resolution")
// Split intents into those we need to push and those which are good to
// resolve.
ir.mu.Lock()
// TODO(tschottdorf): can optimize this and use same underlying slice.
var pushIntents, nonPendingIntents []roachpb.Intent
var pErr *roachpb.Error
for _, intent := range intents {
if intent.Status != roachpb.PENDING {
// The current intent does not need conflict resolution
// because the transaction is already finalized.
// This shouldn't happen as all intents created are in
// the PENDING status.
nonPendingIntents = append(nonPendingIntents, intent)
} else if _, ok := ir.mu.inFlight[*intent.Txn.ID]; ok && skipIfInFlight {
// Another goroutine is working on this transaction so we can
// skip it.
if log.V(1) {
log.Infof("skipping PushTxn for %s; attempt already in flight", intent.Txn.ID)
}
continue
} else {
pushIntents = append(pushIntents, intent)
ir.mu.inFlight[*intent.Txn.ID]++
}
}
ir.mu.Unlock()
if len(nonPendingIntents) > 0 {
return nil, roachpb.NewErrorf("unexpected aborted/resolved intents: %s", nonPendingIntents)
}
// Attempt to push the transaction(s) which created the conflicting intent(s).
var pushReqs []roachpb.Request
for _, intent := range pushIntents {
pushReqs = append(pushReqs, &roachpb.PushTxnRequest{
Span: roachpb.Span{
Key: intent.Txn.Key,
},
PusherTxn: *partialPusherTxn,
PusheeTxn: intent.Txn,
PushTo: h.Timestamp,
// The timestamp is used by PushTxn for figuring out whether the
// transaction is abandoned. If we used the argument's timestamp
// here, we would run into busy loops because that timestamp
// usually stays fixed among retries, so it will never realize
// that a transaction has timed out. See #877.
Now: now,
PushType: pushType,
})
}
// TODO(kaneda): Set the transaction in the header so that the
// txn is correctly propagated in an error response.
b := &client.Batch{}
b.InternalAddRequest(pushReqs...)
br, pErr := ir.store.db.RunWithResponse(b)
ir.mu.Lock()
for _, intent := range pushIntents {
ir.mu.inFlight[*intent.Txn.ID]--
if ir.mu.inFlight[*intent.Txn.ID] == 0 {
delete(ir.mu.inFlight, *intent.Txn.ID)
}
}
ir.mu.Unlock()
if pErr != nil {
return nil, pErr
}
var resolveIntents []roachpb.Intent
for i, intent := range pushIntents {
pushee := br.Responses[i].GetInner().(*roachpb.PushTxnResponse).PusheeTxn
intent.Txn = pushee.TxnMeta
intent.Status = pushee.Status
resolveIntents = append(resolveIntents, intent)
}
return resolveIntents, nil
}
// resolveIntents resolves the given intents. For those which are
// local to the range, we submit directly to the local Raft instance;
// all non-local intents are resolved asynchronously in a batch. If
// `wait` is true, all operations are carried out synchronously and an
// error is returned. Otherwise, the call returns without error as
// soon as all local resolve commands have been **proposed** (not
// executed). This ensures that if a waiting client retries
// immediately after calling this function, it will not hit the same
// intents again.
func (ir *intentResolver) resolveIntents(ctx context.Context, r *Replica,
intents []roachpb.Intent, wait bool, poison bool) error {
// We're doing async stuff below; those need new traces.
ctx, cleanup := tracing.EnsureContext(ctx, ir.store.Tracer())
defer cleanup()
log.Trace(ctx, fmt.Sprintf("resolving intents [wait=%t]", wait))
var reqsRemote []roachpb.Request
baLocal := roachpb.BatchRequest{}
baLocal.Timestamp = ir.store.Clock().Now()
for i := range intents {
intent := intents[i] // avoids a race in `i, intent := range ...`
var resolveArgs roachpb.Request
var local bool // whether this intent lives on this Range
{
if len(intent.EndKey) == 0 {
resolveArgs = &roachpb.ResolveIntentRequest{
Span: intent.Span,
IntentTxn: intent.Txn,
Status: intent.Status,
Poison: poison,
}
local = r.ContainsKey(intent.Key)
} else {
resolveArgs = &roachpb.ResolveIntentRangeRequest{
Span: intent.Span,
IntentTxn: intent.Txn,
Status: intent.Status,
Poison: poison,
}
local = r.ContainsKeyRange(intent.Key, intent.EndKey)
}
}
// If the intent isn't (completely) local, we'll need to send an external request.
// We'll batch them all up and send at the end.
if local {
baLocal.Add(resolveArgs)
} else {
reqsRemote = append(reqsRemote, resolveArgs)
}
}
// The local batch goes directly to Raft.
var wg sync.WaitGroup
if len(baLocal.Requests) > 0 {
action := func() error {
// Trace this under the ID of the intent owner.
// Create a new span though, since we do not want to pass a span
// between goroutines or we risk use-after-finish.
sp := r.store.Tracer().StartSpan("resolve intents")
defer sp.Finish()
ctx = opentracing.ContextWithSpan(ctx, sp)
// Always operate with a timeout when resolving intents: this
// prevents rare shutdown timeouts in tests.
ctxWithTimeout, cancel := context.WithTimeout(ctx, base.NetworkTimeout)
defer cancel()
_, pErr := r.addWriteCmd(ctxWithTimeout, baLocal, &wg)
return pErr.GoError()
}
wg.Add(1)
if wait || !r.store.Stopper().RunLimitedAsyncTask(ir.sem, func() {
if err := action(); err != nil {
log.Warningf("unable to resolve local intents; %s", err)
}
}) {
// Still run the task when draining. Our caller already has a task and
// going async here again is merely for performance, but some intents
// need to be resolved because they might block other tasks. See #1684.
// Note that handleSkippedIntents has a TODO in case #1684 comes back.
if err := action(); err != nil {
return err
}
}
}
// Resolve all of the intents which aren't local to the Range.
if len(reqsRemote) > 0 {
b := &client.Batch{}
b.InternalAddRequest(reqsRemote...)
action := func() error {
// TODO(tschottdorf): no tracing here yet.
return r.store.DB().Run(b).GoError()
}
if wait || !r.store.Stopper().RunLimitedAsyncTask(ir.sem, func() {
if err := action(); err != nil {
log.Warningf("unable to resolve external intents: %s", err)
}
}) {
// As with local intents, try async to not keep the caller waiting, but
// when draining just go ahead and do it synchronously. See #1684.
if err := action(); err != nil {
return err
}
}
}
// Wait until the local ResolveIntents batch has been submitted to
// raft. No-op if all were non-local.
wg.Wait()
return nil
}
// SnapshotWithContext is main implementation for Snapshot() but it takes a
// context to allow tracing.
func (r *Replica) SnapshotWithContext(ctx context.Context) (raftpb.Snapshot, error) {
rangeID := r.RangeID
// If a snapshot is in progress, see if it's ready.
if r.mu.snapshotChan != nil {
select {
case snapData, ok := <-r.mu.snapshotChan:
if ok {
return snapData, nil
}
// If the old channel was closed, fall through to start a new task.
default:
// If the result is not ready, return immediately.
log.Trace(ctx, "snapshot not yet ready")
return raftpb.Snapshot{}, raft.ErrSnapshotTemporarilyUnavailable
}
}
if r.exceedsDoubleSplitSizeLocked() {
maxBytes := r.mu.maxBytes
size := r.mu.state.Stats.Total()
log.Infof(ctx,
"%s: not generating snapshot because replica is too large: %d > 2 * %d",
r, size, maxBytes)
return raftpb.Snapshot{}, raft.ErrSnapshotTemporarilyUnavailable
}
// See if there is already a snapshot running for this store.
if !r.store.AcquireRaftSnapshot() {
log.Trace(ctx, "snapshot already running")
return raftpb.Snapshot{}, raft.ErrSnapshotTemporarilyUnavailable
}
startKey := r.mu.state.Desc.StartKey
// Use an unbuffered channel so the worker stays alive until someone
// reads from the channel, and can abandon the snapshot if it gets stale.
ch := make(chan (raftpb.Snapshot))
if r.store.Stopper().RunAsyncTask(func() {
defer close(ch)
sp := r.store.Tracer().StartSpan("snapshot async")
ctxInner := opentracing.ContextWithSpan(context.Background(), sp)
defer sp.Finish()
snap := r.store.NewSnapshot()
log.Tracef(ctxInner, "new engine snapshot for replica %s", r)
defer snap.Close()
defer r.store.ReleaseRaftSnapshot()
// Delegate to a static function to make sure that we do not depend
// on any indirect calls to r.store.Engine() (or other in-memory
// state of the Replica). Everything must come from the snapshot.
snapData, err := snapshot(context.Background(), snap, rangeID, r.store.raftEntryCache, startKey)
if err != nil {
log.Errorf(ctxInner, "%s: error generating snapshot: %s", r, err)
} else {
log.Trace(ctxInner, "snapshot generated")
r.store.metrics.RangeSnapshotsGenerated.Inc(1)
select {
case ch <- snapData:
log.Trace(ctxInner, "snapshot accepted")
case <-time.After(r.store.ctx.AsyncSnapshotMaxAge):
// If raft decides it doesn't need this snapshot any more (or
// just takes too long to use it), abandon it to save memory.
log.Infof(ctxInner, "%s: abandoning snapshot after %s", r, r.store.ctx.AsyncSnapshotMaxAge)
case <-r.store.Stopper().ShouldQuiesce():
}
}
}) == nil {
r.mu.snapshotChan = ch
} else {
r.store.ReleaseRaftSnapshot()
}
if r.store.ctx.BlockingSnapshotDuration > 0 {
select {
case snap, ok := <-r.mu.snapshotChan:
if ok {
return snap, nil
}
case <-time.After(r.store.ctx.BlockingSnapshotDuration):
log.Trace(ctx, "snapshot blocking duration exceeded")
}
}
return raftpb.Snapshot{}, raft.ErrSnapshotTemporarilyUnavailable
}
// Batch implements the roachpb.KVServer interface.
func (n *Node) Batch(ctx context.Context, args *roachpb.BatchRequest) (*roachpb.BatchResponse, error) {
// TODO(marc): this code is duplicated in kv/db.go, which should be fixed.
// Also, grpc's authentication model (which gives credential access in the
// request handler) doesn't really fit with the current design of the
// security package (which assumes that TLS state is only given at connection
// time) - that should be fixed.
if peer, ok := peer.FromContext(ctx); ok {
if tlsInfo, ok := peer.AuthInfo.(credentials.TLSInfo); ok {
certUser, err := security.GetCertificateUser(&tlsInfo.State)
if err != nil {
return nil, err
}
if certUser != security.NodeUser {
return nil, util.Errorf("user %s is not allowed", certUser)
}
}
}
var br *roachpb.BatchResponse
opName := "node " + strconv.Itoa(int(n.Descriptor.NodeID)) // could save allocs here
fail := func(err error) {
br = &roachpb.BatchResponse{}
br.Error = roachpb.NewError(err)
}
f := func() {
sp, err := tracing.JoinOrNew(n.ctx.Tracer, args.Trace, opName)
if err != nil {
fail(err)
return
}
// If this is a snowball span, it gets special treatment: It skips the
// regular tracing machinery, and we instead send the collected spans
// back with the response. This is more expensive, but then again,
// those are individual requests traced by users, so they can be.
if sp.BaggageItem(tracing.Snowball) != "" {
sp.LogEvent("delegating to snowball tracing")
sp.Finish()
if sp, err = tracing.JoinOrNewSnowball(opName, args.Trace, func(rawSpan basictracer.RawSpan) {
encSp, err := tracing.EncodeRawSpan(&rawSpan, nil)
if err != nil {
log.Warning(err)
}
br.CollectedSpans = append(br.CollectedSpans, encSp)
}); err != nil {
fail(err)
return
}
}
defer sp.Finish()
traceCtx := opentracing.ContextWithSpan(n.context(ctx), sp)
tStart := timeutil.Now()
var pErr *roachpb.Error
br, pErr = n.stores.Send(traceCtx, *args)
if pErr != nil {
br = &roachpb.BatchResponse{}
log.Trace(traceCtx, fmt.Sprintf("error: %T", pErr.GetDetail()))
}
if br.Error != nil {
panic(roachpb.ErrorUnexpectedlySet(n.stores, br))
}
n.metrics.callComplete(timeutil.Since(tStart), pErr)
br.Error = pErr
}
if !n.stopper.RunTask(f) {
return nil, util.Errorf("node %d stopped", n.Descriptor.NodeID)
}
return br, nil
}
// Send implements the batch.Sender interface. If the request is part of a
// transaction, the TxnCoordSender adds the transaction to a map of active
// transactions and begins heartbeating it. Every subsequent request for the
// same transaction updates the lastUpdate timestamp to prevent live
// transactions from being considered abandoned and garbage collected.
// Read/write mutating requests have their key or key range added to the
// transaction's interval tree of key ranges for eventual cleanup via resolved
// write intents; they're tagged to an outgoing EndTransaction request, with
// the receiving replica in charge of resolving them.
func (tc *TxnCoordSender) Send(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
{
// Start new or pick up active trace and embed its trace metadata into
// header for use by RPC recipients. From here on, there's always an active
// Trace, though its overhead is small unless it's sampled.
sp := opentracing.SpanFromContext(ctx)
if sp == nil {
sp = tc.tracer.StartSpan(opTxnCoordSender)
defer sp.Finish()
ctx = opentracing.ContextWithSpan(ctx, sp)
}
// TODO(tschottdorf): To get rid of the spurious alloc below we need to
// implement the carrier interface on ba.Header or make Span non-nullable,
// both of which force all of ba on the Heap. It's already there, so may
// not be a big deal, but ba should live on the stack. Also not easy to use
// a buffer pool here since anything that goes into the RPC layer could be
// used by goroutines we didn't wait for.
if ba.Header.Trace == nil {
ba.Header.Trace = &tracing.Span{}
}
if err := tc.tracer.Inject(sp.Context(), basictracer.Delegator, ba.Trace); err != nil {
return nil, roachpb.NewError(err)
}
}
startNS := tc.clock.PhysicalNow()
if ba.Txn != nil {
// If this request is part of a transaction...
if err := tc.maybeBeginTxn(&ba); err != nil {
return nil, roachpb.NewError(err)
}
var et *roachpb.EndTransactionRequest
var hasET bool
{
var rArgs roachpb.Request
rArgs, hasET = ba.GetArg(roachpb.EndTransaction)
if hasET {
et = rArgs.(*roachpb.EndTransactionRequest)
if len(et.Key) != 0 {
return nil, roachpb.NewErrorf("EndTransaction must not have a Key set")
}
et.Key = ba.Txn.Key
if len(et.IntentSpans) > 0 {
// TODO(tschottdorf): it may be useful to allow this later.
// That would be part of a possible plan to allow txns which
// write on multiple coordinators.
return nil, roachpb.NewErrorf("client must not pass intents to EndTransaction")
}
}
}
if pErr := func() *roachpb.Error {
tc.Lock()
defer tc.Unlock()
if pErr := tc.maybeRejectClientLocked(ctx, *ba.Txn); pErr != nil {
return pErr
}
if !hasET {
return nil
}
// Everything below is carried out only when trying to commit.
// Populate et.IntentSpans, taking into account both any existing
// and new writes, and taking care to perform proper deduplication.
txnMeta := tc.txns[*ba.Txn.ID]
distinctSpans := true
if txnMeta != nil {
et.IntentSpans = txnMeta.keys
// Defensively set distinctSpans to false if we had any previous
// requests in this transaction. This effectively limits the distinct
// spans optimization to 1pc transactions.
distinctSpans = len(txnMeta.keys) == 0
}
ba.IntentSpanIterate(func(key, endKey roachpb.Key) {
et.IntentSpans = append(et.IntentSpans, roachpb.Span{
Key: key,
EndKey: endKey,
})
})
// TODO(peter): Populate DistinctSpans on all batches, not just batches
// which contain an EndTransactionRequest.
ba.Header.DistinctSpans = roachpb.MergeSpans(&et.IntentSpans) && distinctSpans
if len(et.IntentSpans) == 0 {
// If there aren't any intents, then there's factually no
// transaction to end. Read-only txns have all of their state
// in the client.
return roachpb.NewErrorf("cannot commit a read-only transaction")
}
if txnMeta != nil {
txnMeta.keys = et.IntentSpans
}
return nil
}(); pErr != nil {
return nil, pErr
}
if hasET && log.V(1) {
for _, intent := range et.IntentSpans {
log.Trace(ctx, fmt.Sprintf("intent: [%s,%s)",
intent.Key, intent.EndKey))
}
}
}
// Send the command through wrapped sender, taking appropriate measures
// on error.
var br *roachpb.BatchResponse
{
var pErr *roachpb.Error
br, pErr = tc.wrapped.Send(ctx, ba)
if _, ok := pErr.GetDetail().(*roachpb.OpRequiresTxnError); ok {
// TODO(tschottdorf): needs to keep the trace.
br, pErr = tc.resendWithTxn(ba)
}
if pErr = tc.updateState(startNS, ctx, ba, br, pErr); pErr != nil {
log.Trace(ctx, fmt.Sprintf("error: %s", pErr))
return nil, pErr
}
}
if br.Txn == nil {
return br, nil
}
if _, ok := ba.GetArg(roachpb.EndTransaction); !ok {
return br, nil
}
// If the --linearizable flag is set, we want to make sure that
// all the clocks in the system are past the commit timestamp
// of the transaction. This is guaranteed if either
// - the commit timestamp is MaxOffset behind startNS
// - MaxOffset ns were spent in this function
// when returning to the client. Below we choose the option
// that involves less waiting, which is likely the first one
// unless a transaction commits with an odd timestamp.
if tsNS := br.Txn.Timestamp.WallTime; startNS > tsNS {
startNS = tsNS
}
sleepNS := tc.clock.MaxOffset() -
time.Duration(tc.clock.PhysicalNow()-startNS)
if tc.linearizable && sleepNS > 0 {
defer func() {
if log.V(1) {
log.Infof("%v: waiting %s on EndTransaction for linearizability", br.Txn.ID.Short(), util.TruncateDuration(sleepNS, time.Millisecond))
}
time.Sleep(sleepNS)
}()
}
if br.Txn.Status != roachpb.PENDING {
tc.Lock()
tc.cleanupTxnLocked(ctx, *br.Txn)
tc.Unlock()
}
return br, nil
}
// Start starts the test cluster by bootstrapping an in-memory store
// (defaults to maximum of 50M). The server is started, launching the
// node RPC server and all HTTP endpoints. Use the value of
// TestServer.Addr after Start() for client connections. Use Stop()
// to shutdown the server after the test completes.
func (ltc *LocalTestCluster) Start(t util.Tester) {
nodeID := roachpb.NodeID(1)
nodeDesc := &roachpb.NodeDescriptor{NodeID: nodeID}
ltc.tester = t
ltc.Manual = hlc.NewManualClock(0)
ltc.Clock = hlc.NewClock(ltc.Manual.UnixNano)
ltc.Stopper = stop.NewStopper()
rpcContext := rpc.NewContext(testutils.NewNodeTestBaseContext(), ltc.Clock, ltc.Stopper)
ltc.Gossip = gossip.New(rpcContext, nil, ltc.Stopper)
ltc.Eng = engine.NewInMem(roachpb.Attributes{}, 50<<20, ltc.Stopper)
ltc.stores = storage.NewStores(ltc.Clock)
tracer := tracing.NewTracer()
var rpcSend rpcSendFn = func(_ SendOptions, _ ReplicaSlice,
args roachpb.BatchRequest, _ *rpc.Context) (*roachpb.BatchResponse, error) {
if ltc.Latency > 0 {
time.Sleep(ltc.Latency)
}
sp := tracer.StartSpan("node")
defer sp.Finish()
ctx := opentracing.ContextWithSpan(context.Background(), sp)
log.Trace(ctx, args.String())
br, pErr := ltc.stores.Send(ctx, args)
if br == nil {
br = &roachpb.BatchResponse{}
}
if br.Error != nil {
panic(roachpb.ErrorUnexpectedlySet(ltc.stores, br))
}
br.Error = pErr
if pErr != nil {
log.Trace(ctx, "error: "+pErr.String())
}
return br, nil
}
retryOpts := GetDefaultDistSenderRetryOptions()
retryOpts.Closer = ltc.Stopper.ShouldDrain()
ltc.distSender = NewDistSender(&DistSenderContext{
Clock: ltc.Clock,
RangeDescriptorCacheSize: defaultRangeDescriptorCacheSize,
RangeLookupMaxRanges: defaultRangeLookupMaxRanges,
LeaderCacheSize: defaultLeaderCacheSize,
RPCRetryOptions: &retryOpts,
nodeDescriptor: nodeDesc,
RPCSend: rpcSend, // defined above
RangeDescriptorDB: ltc.stores, // for descriptor lookup
}, ltc.Gossip)
ltc.Sender = NewTxnCoordSender(ltc.distSender, ltc.Clock, false /* !linearizable */, tracer,
ltc.Stopper, NewTxnMetrics(metric.NewRegistry()))
ltc.DB = client.NewDB(ltc.Sender)
transport := storage.NewDummyRaftTransport()
ctx := storage.TestStoreContext()
ctx.Clock = ltc.Clock
ctx.DB = ltc.DB
ctx.Gossip = ltc.Gossip
ctx.Transport = transport
ctx.Tracer = tracer
ltc.Store = storage.NewStore(ctx, ltc.Eng, nodeDesc)
if err := ltc.Store.Bootstrap(roachpb.StoreIdent{NodeID: nodeID, StoreID: 1}, ltc.Stopper); err != nil {
t.Fatalf("unable to start local test cluster: %s", err)
}
ltc.stores.AddStore(ltc.Store)
if err := ltc.Store.BootstrapRange(nil); err != nil {
t.Fatalf("unable to start local test cluster: %s", err)
}
if err := ltc.Store.Start(ltc.Stopper); err != nil {
t.Fatalf("unable to start local test cluster: %s", err)
}
ltc.Gossip.SetNodeID(nodeDesc.NodeID)
if err := ltc.Gossip.SetNodeDescriptor(nodeDesc); err != nil {
t.Fatalf("unable to set node descriptor: %s", err)
}
}
// Send sends one or more RPCs to clients specified by the slice of
// replicas. On success, Send returns the first successful reply. Otherwise,
// Send returns an error if and as soon as the number of failed RPCs exceeds
// the available endpoints less the number of required replies.
func send(opts SendOptions, replicas ReplicaSlice,
args roachpb.BatchRequest, rpcContext *rpc.Context) (*roachpb.BatchResponse, error) {
if len(replicas) < 1 {
return nil, roachpb.NewSendError(
fmt.Sprintf("insufficient replicas (%d) to satisfy send request of %d",
len(replicas), 1), false)
}
done := make(chan batchCall, len(replicas))
clients := make([]batchClient, 0, len(replicas))
for _, replica := range replicas {
conn, err := rpcContext.GRPCDial(replica.NodeDesc.Address.String())
if err != nil {
return nil, err
}
argsCopy := args
argsCopy.Replica = replica.ReplicaDescriptor
clients = append(clients, batchClient{
remoteAddr: replica.NodeDesc.Address.String(),
conn: conn,
client: roachpb.NewInternalClient(conn),
args: argsCopy,
})
}
// Put known-unhealthy clients last.
nHealthy, err := splitHealthy(clients)
if err != nil {
return nil, err
}
var orderedClients []batchClient
switch opts.Ordering {
case orderStable:
orderedClients = clients
case orderRandom:
// Randomly permute order, but keep known-unhealthy clients last.
shuffleClients(clients[:nHealthy])
shuffleClients(clients[nHealthy:])
orderedClients = clients
}
// TODO(spencer): going to need to also sort by affinity; closest
// ping time should win. Makes sense to have the rpc client/server
// heartbeat measure ping times. With a bit of seasoning, each
// node will be able to order the healthy replicas based on latency.
// Send the first request.
sendOneFn(opts, rpcContext, orderedClients[0], done)
orderedClients = orderedClients[1:]
var errors, retryableErrors int
// Wait for completions.
var sendNextTimer util.Timer
defer sendNextTimer.Stop()
for {
sendNextTimer.Reset(opts.SendNextTimeout)
select {
case <-sendNextTimer.C:
sendNextTimer.Read = true
// On successive RPC timeouts, send to additional replicas if available.
if len(orderedClients) > 0 {
log.Trace(opts.Context, "timeout, trying next peer")
sendOneFn(opts, rpcContext, orderedClients[0], done)
orderedClients = orderedClients[1:]
}
case call := <-done:
err := call.err
if err == nil {
if log.V(2) {
log.Infof("successful reply: %+v", call.reply)
}
return call.reply, nil
}
// Error handling.
if log.V(1) {
log.Warningf("error reply: %s", err)
}
errors++
// Since we have a reconnecting client here, disconnect errors are retryable.
disconnected := err == io.ErrUnexpectedEOF
if retryErr, ok := err.(retry.Retryable); disconnected || (ok && retryErr.CanRetry()) {
retryableErrors++
}
if remainingNonErrorRPCs := len(replicas) - errors; remainingNonErrorRPCs < 1 {
return nil, roachpb.NewSendError(
fmt.Sprintf("too many errors encountered (%d of %d total): %v",
errors, len(clients), err), remainingNonErrorRPCs+retryableErrors >= 1)
}
// Send to additional replicas if available.
if len(orderedClients) > 0 {
log.Trace(opts.Context, "error, trying next peer")
sendOneFn(opts, rpcContext, orderedClients[0], done)
orderedClients = orderedClients[1:]
}
}
}
}
// 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
}
// initStores initializes the Stores map from ID to Store. Stores are
// added to the local sender if already bootstrapped. A bootstrapped
// Store has a valid ident with cluster, node and Store IDs set. If
// the Store doesn't yet have a valid ident, it's added to the
// bootstraps list for initialization once the cluster and node IDs
// have been determined.
func (n *Node) initStores(
ctx context.Context, engines []engine.Engine, stopper *stop.Stopper,
) error {
var bootstraps []*storage.Store
if len(engines) == 0 {
return errors.Errorf("no engines")
}
for _, e := range engines {
s := storage.NewStore(n.ctx, e, &n.Descriptor)
log.Tracef(ctx, "created store for engine: %s", e)
// Initialize each store in turn, handling un-bootstrapped errors by
// adding the store to the bootstraps list.
if err := s.Start(ctx, stopper); err != nil {
if _, ok := err.(*storage.NotBootstrappedError); ok {
log.Infof(ctx, "store %s not bootstrapped", s)
bootstraps = append(bootstraps, s)
continue
}
return errors.Errorf("failed to start store: %s", err)
}
if s.Ident.ClusterID == *uuid.EmptyUUID || s.Ident.NodeID == 0 {
return errors.Errorf("unidentified store: %s", s)
}
capacity, err := s.Capacity()
if err != nil {
return errors.Errorf("could not query store capacity: %s", err)
}
log.Infof(ctx, "initialized store %s: %+v", s, capacity)
n.addStore(s)
}
// If there are no initialized stores and no gossip resolvers,
// bootstrap this node as the seed of a new cluster.
if n.stores.GetStoreCount() == 0 {
resolvers := n.ctx.Gossip.GetResolvers()
// Check for the case of uninitialized node having only itself specified as join host.
switch len(resolvers) {
case 0:
return errNeedsBootstrap
case 1:
if resolvers[0].Addr() == n.Descriptor.Address.String() {
return errCannotJoinSelf
}
}
}
// Verify all initialized stores agree on cluster and node IDs.
if err := n.validateStores(); err != nil {
return err
}
log.Trace(ctx, "validated stores")
// Set the stores map as the gossip persistent storage, so that
// gossip can bootstrap using the most recently persisted set of
// node addresses.
if err := n.ctx.Gossip.SetStorage(n.stores); err != nil {
return fmt.Errorf("failed to initialize the gossip interface: %s", err)
}
// Connect gossip before starting bootstrap. For new nodes, connecting
// to the gossip network is necessary to get the cluster ID.
n.connectGossip()
log.Trace(ctx, "connected to gossip")
// If no NodeID has been assigned yet, allocate a new node ID by
// supplying 0 to initNodeID.
if n.Descriptor.NodeID == 0 {
n.initNodeID(0)
n.initialBoot = true
log.Tracef(ctx, "allocated node ID %d", n.Descriptor.NodeID)
}
// Bootstrap any uninitialized stores asynchronously.
if len(bootstraps) > 0 {
if err := stopper.RunAsyncTask(func() {
n.bootstrapStores(n.Ctx(), bootstraps, stopper)
}); err != nil {
return err
}
}
return nil
}
// sendToReplicas sends one or more RPCs to clients specified by the slice of
// replicas. On success, Send returns the first successful reply. Otherwise,
// Send returns an error if and as soon as the number of failed RPCs exceeds
// the available endpoints less the number of required replies.
func (ds *DistSender) sendToReplicas(
opts SendOptions,
rangeID roachpb.RangeID,
replicas ReplicaSlice,
args roachpb.BatchRequest,
rpcContext *rpc.Context,
) (*roachpb.BatchResponse, error) {
if len(replicas) < 1 {
return nil, roachpb.NewSendError(
fmt.Sprintf("insufficient replicas (%d) to satisfy send request of %d",
len(replicas), 1))
}
done := make(chan BatchCall, len(replicas))
transportFactory := opts.transportFactory
if transportFactory == nil {
transportFactory = grpcTransportFactory
}
transport, err := transportFactory(opts, rpcContext, replicas, args)
if err != nil {
return nil, err
}
defer transport.Close()
if transport.IsExhausted() {
return nil, roachpb.NewSendError(
fmt.Sprintf("sending to all %d replicas failed", len(replicas)))
}
// Send the first request.
pending := 1
transport.SendNext(done)
// Wait for completions. This loop will retry operations that fail
// with errors that reflect per-replica state and may succeed on
// other replicas.
var sendNextTimer timeutil.Timer
defer sendNextTimer.Stop()
for {
sendNextTimer.Reset(opts.SendNextTimeout)
select {
case <-sendNextTimer.C:
sendNextTimer.Read = true
// On successive RPC timeouts, send to additional replicas if available.
if !transport.IsExhausted() {
log.Trace(opts.Context, "timeout, trying next peer")
pending++
transport.SendNext(done)
}
case call := <-done:
pending--
err := call.Err
if err == nil {
if log.V(2) {
log.Infof(opts.Context, "RPC reply: %+v", call.Reply)
} else if log.V(1) && call.Reply.Error != nil {
log.Infof(opts.Context, "application error: %s", call.Reply.Error)
}
if !ds.handlePerReplicaError(rangeID, call.Reply.Error) {
return call.Reply, nil
}
// Extract the detail so it can be included in the error
// message if this is our last replica.
//
// TODO(bdarnell): The last error is not necessarily the best
// one to return; we may want to remember the "best" error
// we've seen (for example, a NotLeaseHolderError conveys more
// information than a RangeNotFound).
err = call.Reply.Error.GoError()
} else if log.V(1) {
log.Warningf(opts.Context, "RPC error: %s", err)
}
// Send to additional replicas if available.
if !transport.IsExhausted() {
log.Tracef(opts.Context, "error, trying next peer: %s", err)
pending++
transport.SendNext(done)
}
if pending == 0 {
return nil, roachpb.NewSendError(
fmt.Sprintf("sending to all %d replicas failed; last error: %v",
len(replicas), err))
}
}
}
}
// Start starts the server on the specified port, starts gossip and initializes
// the node using the engines from the server's context.
//
// The passed context can be used to trace the server startup. The context
// should represent the general startup operation, and is different from
// contexts used at runtime for server's background work (like `s.Ctx()`).
func (s *Server) Start(ctx context.Context) error {
// Copy log tags from s.Ctx()
ctx = log.WithLogTagsFromCtx(ctx, s.Ctx())
tlsConfig, err := s.ctx.GetServerTLSConfig()
if err != nil {
return err
}
httpServer := netutil.MakeServer(s.stopper, tlsConfig, s)
plainRedirectServer := netutil.MakeServer(s.stopper, tlsConfig, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, "https://"+r.Host+r.RequestURI, http.StatusPermanentRedirect)
}))
// The following code is a specialization of util/net.go's ListenAndServe
// which adds pgwire support. A single port is used to serve all protocols
// (pg, http, h2) via the following construction:
//
// non-TLS case:
// net.Listen -> cmux.New
// |
// - -> pgwire.Match -> pgwire.Server.ServeConn
// - -> cmux.Any -> grpc.(*Server).Serve
//
// TLS case:
// net.Listen -> cmux.New
// |
// - -> pgwire.Match -> pgwire.Server.ServeConn
// - -> cmux.Any -> grpc.(*Server).Serve
//
// Note that the difference between the TLS and non-TLS cases exists due to
// Go's lack of an h2c (HTTP2 Clear Text) implementation. See inline comments
// in util.ListenAndServe for an explanation of how h2c is implemented there
// and here.
ln, err := net.Listen("tcp", s.ctx.Addr)
if err != nil {
return err
}
log.Tracef(ctx, "listening on port %s", s.ctx.Addr)
unresolvedAddr, err := officialAddr(s.ctx.Addr, ln.Addr())
if err != nil {
return err
}
s.ctx.Addr = unresolvedAddr.String()
s.rpcContext.SetLocalInternalServer(s.node)
m := cmux.New(ln)
pgL := m.Match(pgwire.Match)
anyL := m.Match(cmux.Any())
httpLn, err := net.Listen("tcp", s.ctx.HTTPAddr)
if err != nil {
return err
}
unresolvedHTTPAddr, err := officialAddr(s.ctx.HTTPAddr, httpLn.Addr())
if err != nil {
return err
}
s.ctx.HTTPAddr = unresolvedHTTPAddr.String()
s.stopper.RunWorker(func() {
<-s.stopper.ShouldQuiesce()
if err := httpLn.Close(); err != nil {
log.Fatal(s.Ctx(), err)
}
})
if tlsConfig != nil {
httpMux := cmux.New(httpLn)
clearL := httpMux.Match(cmux.HTTP1())
tlsL := httpMux.Match(cmux.Any())
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(httpMux.Serve())
})
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(plainRedirectServer.Serve(clearL))
})
httpLn = tls.NewListener(tlsL, tlsConfig)
}
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(httpServer.Serve(httpLn))
})
s.stopper.RunWorker(func() {
<-s.stopper.ShouldQuiesce()
netutil.FatalIfUnexpected(anyL.Close())
<-s.stopper.ShouldStop()
s.grpc.Stop()
})
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(s.grpc.Serve(anyL))
})
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(httpServer.ServeWith(s.stopper, pgL, func(conn net.Conn) {
if err := s.pgServer.ServeConn(conn); err != nil && !netutil.IsClosedConnection(err) {
log.Error(s.Ctx(), err)
}
}))
})
if len(s.ctx.SocketFile) != 0 {
// Unix socket enabled: postgres protocol only.
unixLn, err := net.Listen("unix", s.ctx.SocketFile)
if err != nil {
return err
}
s.stopper.RunWorker(func() {
<-s.stopper.ShouldQuiesce()
if err := unixLn.Close(); err != nil {
log.Fatal(s.Ctx(), err)
}
})
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(httpServer.ServeWith(s.stopper, unixLn, func(conn net.Conn) {
if err := s.pgServer.ServeConn(conn); err != nil &&
!netutil.IsClosedConnection(err) {
log.Error(s.Ctx(), err)
}
}))
})
}
// Enable the debug endpoints first to provide an earlier window
// into what's going on with the node in advance of exporting node
// functionality.
// TODO(marc): when cookie-based authentication exists,
// apply it for all web endpoints.
s.mux.HandleFunc(debugEndpoint, http.HandlerFunc(handleDebug))
s.gossip.Start(unresolvedAddr)
log.Trace(ctx, "started gossip")
if err := s.node.start(ctx, unresolvedAddr, s.ctx.Engines, s.ctx.NodeAttributes); err != nil {
return err
}
log.Trace(ctx, "started node")
// Set the NodeID in the base context (which was inherited by the
// various components of the server).
s.nodeLogTagVal.Set(int64(s.node.Descriptor.NodeID))
// We can now add the node registry.
s.recorder.AddNode(s.registry, s.node.Descriptor, s.node.startedAt)
// Begin recording runtime statistics.
s.startSampleEnvironment(s.ctx.MetricsSampleInterval)
// Begin recording time series data collected by the status monitor.
s.tsDB.PollSource(s.recorder, s.ctx.MetricsSampleInterval, ts.Resolution10s, s.stopper)
// Begin recording status summaries.
s.node.startWriteSummaries(s.ctx.MetricsSampleInterval)
s.sqlExecutor.SetNodeID(s.node.Descriptor.NodeID)
// Create and start the schema change manager only after a NodeID
// has been assigned.
testingKnobs := new(sql.SchemaChangeManagerTestingKnobs)
if s.ctx.TestingKnobs.SQLSchemaChangeManager != nil {
testingKnobs = s.ctx.TestingKnobs.SQLSchemaChangeManager.(*sql.SchemaChangeManagerTestingKnobs)
}
sql.NewSchemaChangeManager(testingKnobs, *s.db, s.gossip, s.leaseMgr).Start(s.stopper)
log.Infof(s.Ctx(), "starting %s server at %s", s.ctx.HTTPRequestScheme(), unresolvedHTTPAddr)
log.Infof(s.Ctx(), "starting grpc/postgres server at %s", unresolvedAddr)
if len(s.ctx.SocketFile) != 0 {
log.Infof(s.Ctx(), "starting postgres server at unix:%s", s.ctx.SocketFile)
}
s.stopper.RunWorker(func() {
netutil.FatalIfUnexpected(m.Serve())
})
log.Trace(ctx, "accepting connections")
// Initialize grpc-gateway mux and context.
jsonpb := &util.JSONPb{
EnumsAsInts: true,
EmitDefaults: true,
Indent: " ",
}
protopb := new(util.ProtoPb)
gwMux := gwruntime.NewServeMux(
gwruntime.WithMarshalerOption(gwruntime.MIMEWildcard, jsonpb),
gwruntime.WithMarshalerOption(util.JSONContentType, jsonpb),
gwruntime.WithMarshalerOption(util.AltJSONContentType, jsonpb),
gwruntime.WithMarshalerOption(util.ProtoContentType, protopb),
gwruntime.WithMarshalerOption(util.AltProtoContentType, protopb),
)
gwCtx, gwCancel := context.WithCancel(s.Ctx())
s.stopper.AddCloser(stop.CloserFn(gwCancel))
// Setup HTTP<->gRPC handlers.
conn, err := s.rpcContext.GRPCDial(s.ctx.Addr)
if err != nil {
return errors.Errorf("error constructing grpc-gateway: %s; are your certificates valid?", err)
}
for _, gw := range []grpcGatewayServer{&s.admin, s.status, &s.tsServer} {
if err := gw.RegisterGateway(gwCtx, gwMux, conn); err != nil {
return err
}
}
var uiFileSystem http.FileSystem
uiDebug := envutil.EnvOrDefaultBool("COCKROACH_DEBUG_UI", false)
if uiDebug {
uiFileSystem = http.Dir("ui")
} else {
uiFileSystem = &assetfs.AssetFS{
Asset: ui.Asset,
AssetDir: ui.AssetDir,
AssetInfo: ui.AssetInfo,
}
}
uiFileServer := http.FileServer(uiFileSystem)
s.mux.HandleFunc("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/" {
if uiDebug {
r.URL.Path = "debug.html"
} else {
r.URL.Path = "release.html"
}
}
uiFileServer.ServeHTTP(w, r)
}))
// TODO(marc): when cookie-based authentication exists,
// apply it for all web endpoints.
s.mux.Handle(adminEndpoint, gwMux)
s.mux.Handle(ts.URLPrefix, gwMux)
s.mux.Handle(statusPrefix, s.status)
s.mux.Handle(healthEndpoint, s.status)
log.Trace(ctx, "added http endpoints")
if err := sdnotify.Ready(); err != nil {
log.Errorf(s.Ctx(), "failed to signal readiness using systemd protocol: %s", err)
}
log.Trace(ctx, "server ready")
return nil
}
func (tc *TxnCoordSender) heartbeat(ctx context.Context, txnID uuid.UUID) bool {
tc.Lock()
proceed := true
txnMeta := tc.txns[txnID]
var intentSpans []roachpb.Span
// Before we send a heartbeat, determine whether this transaction
// should be considered abandoned. If so, exit heartbeat.
if txnMeta.hasClientAbandonedCoord(tc.clock.PhysicalNow()) {
// TODO(tschottdorf): should we be more proactive here?
// The client might be continuing the transaction
// through another coordinator, but in the most likely
// case it's just gone and the open transaction record
// could block concurrent operations.
if log.V(1) {
log.Infof("transaction %s abandoned; stopping heartbeat",
txnMeta.txn)
}
proceed = false
// Grab the intents here to avoid potential race.
intentSpans = collectIntentSpans(txnMeta.keys)
txnMeta.keys.Clear()
}
// txnMeta.txn is possibly replaced concurrently,
// so grab a copy before unlocking.
txn := txnMeta.txn.Clone()
tc.Unlock()
ba := roachpb.BatchRequest{}
ba.Txn = &txn
if !proceed {
// Actively abort the transaction and its intents since we assume it's abandoned.
et := &roachpb.EndTransactionRequest{
Span: roachpb.Span{
Key: txn.Key,
},
Commit: false,
IntentSpans: intentSpans,
}
ba.Add(et)
tc.stopper.RunAsyncTask(func() {
// Use the wrapped sender since the normal Sender
// does not allow clients to specify intents.
// TODO(tschottdorf): not using the existing context here since that
// leads to use-after-finish of the contained trace. Should fork off
// before the goroutine.
if _, pErr := tc.wrapped.Send(context.Background(), ba); pErr != nil {
if log.V(1) {
log.Warningf("abort due to inactivity failed for %s: %s ", txn, pErr)
}
}
})
return false
}
hb := &roachpb.HeartbeatTxnRequest{
Now: tc.clock.Now(),
}
hb.Key = txn.Key
ba.Add(hb)
log.Trace(ctx, "heartbeat")
_, err := tc.wrapped.Send(ctx, ba)
// If the transaction is not in pending state, then we can stop
// the heartbeat. It's either aborted or committed, and we resolve
// write intents accordingly.
if err != nil {
log.Warningf("heartbeat to %s failed: %s", txn, err)
}
// TODO(bdarnell): once we have gotten a heartbeat response with
// Status != PENDING, future heartbeats are useless. However, we
// need to continue the heartbeatLoop until the client either
// commits or abandons the transaction. We could save a little
// pointless work by restructuring this loop to stop sending
// heartbeats between the time that the transaction is aborted and
// the client finds out. Furthermore, we could use this information
// to send TransactionAbortedErrors to the client so it can restart
// immediately instead of running until its EndTransaction.
return true
}
// lookupRangeDescriptorInternal is called from LookupRangeDescriptor or from tests.
//
// If a WaitGroup is supplied, it is signaled when the request is
// added to the inflight request map (with or without merging) or the
// function finishes. Used for testing.
func (rdc *rangeDescriptorCache) lookupRangeDescriptorInternal(
ctx context.Context,
key roachpb.RKey,
evictToken *evictionToken,
considerIntents bool,
useReverseScan bool,
wg *sync.WaitGroup,
) (*roachpb.RangeDescriptor, *evictionToken, error) {
rdc.rangeCache.RLock()
doneWg := func() {
if wg != nil {
wg.Done()
}
wg = nil
}
defer doneWg()
if _, desc, err := rdc.getCachedRangeDescriptorLocked(key, useReverseScan); err != nil {
rdc.rangeCache.RUnlock()
return nil, nil, err
} else if desc != nil {
rdc.rangeCache.RUnlock()
returnToken := rdc.makeEvictionToken(desc, func() error {
return rdc.evictCachedRangeDescriptorLocked(key, desc, useReverseScan)
})
log.Trace(ctx, "looked up range descriptor from cache")
return desc, returnToken, nil
}
if log.V(3) {
log.Infof(ctx, "lookup range descriptor: key=%s\n%s", key, rdc.stringLocked())
} else if log.V(2) {
log.Infof(ctx, "lookup range descriptor: key=%s", key)
}
var res lookupResult
requestKey := makeLookupRequestKey(key, evictToken, considerIntents, useReverseScan)
rdc.lookupRequests.Lock()
if req, inflight := rdc.lookupRequests.inflight[requestKey]; inflight {
resC := make(chan lookupResult, 1)
req.observers = append(req.observers, resC)
rdc.lookupRequests.inflight[requestKey] = req
rdc.lookupRequests.Unlock()
rdc.rangeCache.RUnlock()
doneWg()
res = <-resC
log.Trace(ctx, "looked up range descriptor with shared request")
} else {
rdc.lookupRequests.inflight[requestKey] = req
rdc.lookupRequests.Unlock()
rdc.rangeCache.RUnlock()
doneWg()
rs, preRs, err := rdc.performRangeLookup(ctx, key, considerIntents, useReverseScan)
if err != nil {
res = lookupResult{err: err}
} else {
switch len(rs) {
case 0:
res = lookupResult{err: fmt.Errorf("no range descriptors returned for %s", key)}
case 1:
desc := &rs[0]
res = lookupResult{
desc: desc,
evictToken: rdc.makeEvictionToken(desc, func() error {
return rdc.evictCachedRangeDescriptorLocked(key, desc, useReverseScan)
}),
}
case 2:
if !considerIntents {
panic(fmt.Sprintf("more than 1 matching range descriptor returned for %s when not considering intents: %v", key, rs))
}
desc := &rs[0]
nextDesc := rs[1]
res = lookupResult{
desc: desc,
evictToken: rdc.makeEvictionToken(desc, func() error {
return rdc.insertRangeDescriptorsLocked(nextDesc)
}),
}
default:
panic(fmt.Sprintf("more than 2 matching range descriptors returned for %s: %v", key, rs))
}
}
// We want to be assured that all goroutines which experienced a cache miss
// have joined our in-flight request, and all others will experience a
// cache hit. This requires atomicity across cache population and
// notification, hence this exclusive lock.
rdc.rangeCache.Lock()
if res.err == nil {
// These need to be separate because we need to preserve the pointer to rs[0]
// so that the seenDesc logic works correctly in EvictCachedRangeDescriptor. An
// append could cause a copy, which would change the address of rs[0]. We insert
// the prefetched descriptors first to avoid any unintended overwriting.
if err := rdc.insertRangeDescriptorsLocked(preRs...); err != nil {
log.Warningf(ctx, "range cache inserting prefetched descriptors failed: %v", err)
}
if err := rdc.insertRangeDescriptorsLocked(rs...); err != nil {
res = lookupResult{err: err}
}
}
// rdc.lookupRequests does not need to be locked here because we hold an exclusive
// write lock on rdc.rangeCache. However, we do anyway for clarity and future proofing.
rdc.lookupRequests.Lock()
for _, observer := range rdc.lookupRequests.inflight[requestKey].observers {
observer <- res
}
delete(rdc.lookupRequests.inflight, requestKey)
rdc.lookupRequests.Unlock()
rdc.rangeCache.Unlock()
log.Trace(ctx, "looked up range descriptor")
}
// It rarely may be possible that we somehow got grouped in with the
// wrong RangeLookup (eg. from a double split), so if we did, return
// a retryable lookupMismatchError with an unmodified eviction token.
if res.desc != nil {
if (!useReverseScan && !res.desc.ContainsKey(key)) || (useReverseScan && !res.desc.ContainsExclusiveEndKey(key)) {
return nil, evictToken, lookupMismatchError{
desiredKey: key,
mismatchedDesc: res.desc,
}
}
}
return res.desc, res.evictToken, res.err
}
// sendChunk is in charge of sending an "admissible" piece of batch, i.e. one
// which doesn't need to be subdivided further before going to a range (so no
// mixing of forward and reverse scans, etc). The parameters and return values
// correspond to client.Sender with the exception of the returned boolean,
// which is true when indicating that the caller should retry but needs to send
// EndTransaction in a separate request.
func (ds *DistSender) sendChunk(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error, bool) {
isReverse := ba.IsReverse()
ctx, cleanup := tracing.EnsureContext(ctx, ds.Tracer)
defer cleanup()
// The minimal key range encompassing all requests contained within.
// Local addressing has already been resolved.
// TODO(tschottdorf): consider rudimentary validation of the batch here
// (for example, non-range requests with EndKey, or empty key ranges).
rs, err := keys.Range(ba)
if err != nil {
return nil, roachpb.NewError(err), false
}
var br *roachpb.BatchResponse
// Send the request to one range per iteration.
for {
// Increase the sequence counter only once before sending RPCs to
// the ranges involved in this chunk of the batch (as opposed to for
// each RPC individually). On RPC errors, there's no guarantee that
// the request hasn't made its way to the target regardless of the
// error; we'd like the second execution to be caught by the sequence
// cache if that happens. There is a small chance that that we address
// a range twice in this chunk (stale/suboptimal descriptors due to
// splits/merges) which leads to a transaction retry.
// TODO(tschottdorf): it's possible that if we don't evict from the
// cache we could be in for a busy loop.
ba.SetNewRequest()
var curReply *roachpb.BatchResponse
var desc *roachpb.RangeDescriptor
var evictToken evictionToken
var needAnother bool
var pErr *roachpb.Error
var finished bool
for r := retry.Start(ds.rpcRetryOptions); r.Next(); {
// Get range descriptor (or, when spanning range, descriptors). Our
// error handling below may clear them on certain errors, so we
// refresh (likely from the cache) on every retry.
log.Trace(ctx, "meta descriptor lookup")
desc, needAnother, evictToken, pErr = ds.getDescriptors(rs, evictToken, isReverse)
// getDescriptors may fail retryably if the first range isn't
// available via Gossip.
if pErr != nil {
log.Trace(ctx, "range descriptor lookup failed: "+pErr.String())
if pErr.Retryable {
if log.V(1) {
log.Warning(pErr)
}
continue
}
break
} else {
log.Trace(ctx, "looked up range descriptor")
}
if needAnother && br == nil {
// TODO(tschottdorf): we should have a mechanism for discovering
// range merges (descriptor staleness will mostly go unnoticed),
// or we'll be turning single-range queries into multi-range
// queries for no good reason.
// If there's no transaction and op spans ranges, possibly
// re-run as part of a transaction for consistency. The
// case where we don't need to re-run is if the read
// consistency is not required.
if ba.Txn == nil && ba.IsPossibleTransaction() &&
ba.ReadConsistency != roachpb.INCONSISTENT {
return nil, roachpb.NewError(&roachpb.OpRequiresTxnError{}), false
}
// If the request is more than but ends with EndTransaction, we
// want the caller to come again with the EndTransaction in an
// extra call.
if l := len(ba.Requests) - 1; l > 0 && ba.Requests[l].GetInner().Method() == roachpb.EndTransaction {
return nil, roachpb.NewError(errors.New("cannot send 1PC txn to multiple ranges")), true /* shouldSplitET */
}
}
// It's possible that the returned descriptor misses parts of the
// keys it's supposed to scan after it's truncated to match the
// descriptor. Example revscan [a,g), first desc lookup for "g"
// returns descriptor [c,d) -> [d,g) is never scanned.
// We evict and retry in such a case.
includesFrontOfCurSpan := func(rd *roachpb.RangeDescriptor) bool {
if isReverse {
// This approach is needed because rs.EndKey is exclusive.
return desc.ContainsKeyRange(desc.StartKey, rs.EndKey)
}
return desc.ContainsKey(rs.Key)
}
if !includesFrontOfCurSpan(desc) {
if err := evictToken.Evict(); err != nil {
return nil, roachpb.NewError(err), false
}
// On addressing errors, don't backoff; retry immediately.
r.Reset()
continue
}
curReply, pErr = func() (*roachpb.BatchResponse, *roachpb.Error) {
// Truncate the request to our current key range.
intersected, iErr := rs.Intersect(desc)
if iErr != nil {
return nil, roachpb.NewError(iErr)
}
truncBA, numActive, trErr := truncate(ba, intersected)
if numActive == 0 && trErr == nil {
// This shouldn't happen in the wild, but some tests
// exercise it.
return nil, roachpb.NewErrorf("truncation resulted in empty batch on [%s,%s): %s",
rs.Key, rs.EndKey, ba)
}
if trErr != nil {
return nil, roachpb.NewError(trErr)
}
return ds.sendSingleRange(ctx, truncBA, desc)
}()
// If sending succeeded, break this loop.
if pErr == nil {
finished = true
break
}
if log.V(1) {
log.Warningf("failed to invoke %s: %s", ba, pErr)
}
log.Trace(ctx, fmt.Sprintf("reply error: %T", pErr.GetDetail()))
// Error handling below.
// If retryable, allow retry. For range not found or range
// key mismatch errors, we don't backoff on the retry,
// but reset the backoff loop so we can retry immediately.
switch tErr := pErr.GetDetail().(type) {
case *roachpb.SendError:
// For an RPC error to occur, we must've been unable to contact
// any replicas. In this case, likely all nodes are down (or
// not getting back to us within a reasonable amount of time).
// We may simply not be trying to talk to the up-to-date
// replicas, so clearing the descriptor here should be a good
// idea.
if err := evictToken.Evict(); err != nil {
return nil, roachpb.NewError(err), false
}
if tErr.CanRetry() {
continue
}
case *roachpb.RangeNotFoundError:
// Range descriptor might be out of date - evict it. This is
// likely the result of a rebalance.
if err := evictToken.Evict(); err != nil {
return nil, roachpb.NewError(err), false
}
// On addressing errors, don't backoff; retry immediately.
r.Reset()
if log.V(1) {
log.Warning(tErr)
}
continue
case *roachpb.RangeKeyMismatchError:
// Range descriptor might be out of date - evict it. This is
// likely the result of a range split. If we have new range
// descriptors, insert them instead as long as they are different
// from the last descriptor to avoid endless loops.
var replacements []roachpb.RangeDescriptor
different := func(rd *roachpb.RangeDescriptor) bool {
return !desc.RSpan().Equal(rd.RSpan())
}
if tErr.MismatchedRange != nil && different(tErr.MismatchedRange) {
replacements = append(replacements, *tErr.MismatchedRange)
}
if tErr.SuggestedRange != nil && different(tErr.SuggestedRange) {
if includesFrontOfCurSpan(tErr.SuggestedRange) {
replacements = append(replacements, *tErr.SuggestedRange)
}
}
// Same as Evict() if replacements is empty.
if err := evictToken.EvictAndReplace(replacements...); err != nil {
return nil, roachpb.NewError(err), false
}
// On addressing errors, don't backoff; retry immediately.
r.Reset()
if log.V(1) {
log.Warning(tErr)
}
continue
case *roachpb.NotLeaderError:
newLeader := tErr.Leader
if newLeader != nil {
// Verify that leader is a known replica according to the
// descriptor. If not, we've got a stale range descriptor;
// evict cache.
if i, _ := desc.FindReplica(newLeader.StoreID); i == -1 {
if log.V(1) {
log.Infof("error indicates unknown leader %s, expunging descriptor %s", newLeader, desc)
}
if err := evictToken.Evict(); err != nil {
return nil, roachpb.NewError(err), false
}
}
} else {
// If the new leader is unknown, we were talking to a
// replica that is partitioned away from the majority. Our
// range descriptor may be stale, so clear the cache.
//
// TODO(bdarnell): An unknown-leader error doesn't
// necessarily mean our descriptor is stale. Ideally we
// would treat these errors more like SendError: retry on
// another node (at a lower level), and then if it reaches
// this level then we know we've exhausted our options and
// must clear the cache.
if err := evictToken.Evict(); err != nil {
return nil, roachpb.NewError(err), false
}
newLeader = &roachpb.ReplicaDescriptor{}
}
// Next, cache the new leader.
ds.updateLeaderCache(roachpb.RangeID(desc.RangeID), *newLeader)
if log.V(1) {
log.Warning(tErr)
}
r.Reset()
continue
case retry.Retryable:
if tErr.CanRetry() {
if log.V(1) {
log.Warning(tErr)
}
continue
}
}
break
}
// Immediately return if querying a range failed non-retryably.
if pErr != nil {
return nil, pErr, false
} else if !finished {
select {
case <-ds.rpcRetryOptions.Closer:
return nil, roachpb.NewError(&roachpb.NodeUnavailableError{}), false
default:
log.Fatal("exited retry loop with nil error but finished=false")
}
}
ba.Txn.Update(curReply.Txn)
if br == nil {
// First response from a Range.
br = curReply
} else {
// This was the second or later call in a cross-Range request.
// Combine the new response with the existing one.
if err := br.Combine(curReply); err != nil {
return nil, roachpb.NewError(err), false
}
}
if ba.MaxScanResults > 0 {
// Count how many results we received.
var numResults int64
for _, resp := range curReply.Responses {
if cResp, ok := resp.GetInner().(roachpb.Countable); ok {
numResults += cResp.Count()
}
}
if numResults > ba.MaxScanResults {
panic(fmt.Sprintf("received %d results, limit was %d", numResults, ba.MaxScanResults))
}
ba.MaxScanResults -= numResults
if ba.MaxScanResults == 0 {
// We are done with this batch. Some requests might have NoopResponses; we must
// replace them with empty responses of the proper type.
for i, req := range ba.Requests {
if _, ok := br.Responses[i].GetInner().(*roachpb.NoopResponse); !ok {
continue
}
union := roachpb.ResponseUnion{}
var reply roachpb.Response
if _, ok := req.GetInner().(*roachpb.ScanRequest); ok {
reply = &roachpb.ScanResponse{}
} else {
_ = req.GetInner().(*roachpb.ReverseScanRequest)
reply = &roachpb.ReverseScanResponse{}
}
union.MustSetInner(reply)
br.Responses[i] = union
}
return br, nil, false
}
}
// If this request has a bound (such as MaxResults in
// ScanRequest) and we are going to query at least one more range,
// check whether enough rows have been retrieved.
// TODO(tschottdorf): need tests for executing a multi-range batch
// with various bounded requests which saturate at different times.
if needAnother {
// Start with the assumption that all requests are saturated.
// Below, we look at each and decide whether that's true.
// Everything that is indeed saturated is "masked out" from the
// batch request; only if that's all requests does needAnother
// remain false.
needAnother = false
if br == nil {
// Clone ba.Requests. This is because we're multi-range, and
// some requests may be bounded, which could lead to them being
// masked out once they're saturated. We don't want to risk
// removing requests that way in the "master copy" since that
// could lead to omitting requests in certain retry scenarios.
ba.Requests = append([]roachpb.RequestUnion(nil), ba.Requests...)
}
for i, union := range ba.Requests {
args := union.GetInner()
if _, ok := args.(*roachpb.NoopRequest); ok {
// NoopRequests are skipped.
continue
}
boundedArg, ok := args.(roachpb.Bounded)
if !ok {
// Non-bounded request. We will have to query all ranges.
needAnother = true
continue
}
prevBound := boundedArg.GetBound()
cReply, ok := curReply.Responses[i].GetInner().(roachpb.Countable)
if !ok || prevBound <= 0 {
// Request bounded, but without max results. Again, will
// need to query everything we can. The case in which the reply
// isn't countable occurs when the request wasn't active for
// that range (since it didn't apply to it), so the response
// is a NoopResponse.
needAnother = true
continue
}
nextBound := prevBound - cReply.Count()
if nextBound <= 0 {
// We've hit max results for this piece of the batch. Mask
// it out (we've copied the requests slice above, so this
// is kosher).
union := &ba.Requests[i] // avoid working on copy
union.MustSetInner(&noopRequest)
continue
}
// The request isn't saturated yet.
needAnother = true
boundedArg.SetBound(nextBound)
}
}
// If this was the last range accessed by this call, exit loop.
if !needAnother {
return br, nil, false
}
if isReverse {
// In next iteration, query previous range.
// We use the StartKey of the current descriptor as opposed to the
// EndKey of the previous one since that doesn't have bugs when
// stale descriptors come into play.
rs.EndKey, err = prev(ba, desc.StartKey)
} else {
// In next iteration, query next range.
// It's important that we use the EndKey of the current descriptor
// as opposed to the StartKey of the next one: if the former is stale,
// it's possible that the next range has since merged the subsequent
// one, and unless both descriptors are stale, the next descriptor's
// StartKey would move us to the beginning of the current range,
// resulting in a duplicate scan.
rs.Key, err = next(ba, desc.EndKey)
}
if err != nil {
return nil, roachpb.NewError(err), false
}
log.Trace(ctx, "querying next range")
}
}
func (rq *replicateQueue) process(
ctx context.Context,
now hlc.Timestamp,
repl *Replica,
sysCfg config.SystemConfig,
) error {
desc := repl.Desc()
// Find the zone config for this range.
zone, err := sysCfg.GetZoneConfigForKey(desc.StartKey)
if err != nil {
return err
}
action, _ := rq.allocator.ComputeAction(zone, desc)
// Avoid taking action if the range has too many dead replicas to make
// quorum.
deadReplicas := rq.allocator.storePool.deadReplicas(repl.RangeID, desc.Replicas)
quorum := computeQuorum(len(desc.Replicas))
liveReplicaCount := len(desc.Replicas) - len(deadReplicas)
if liveReplicaCount < quorum {
return errors.Errorf("range requires a replication change, but lacks a quorum of live nodes.")
}
switch action {
case AllocatorAdd:
log.Trace(ctx, "adding a new replica")
newStore, err := rq.allocator.AllocateTarget(zone.ReplicaAttrs[0], desc.Replicas, true)
if err != nil {
return err
}
newReplica := roachpb.ReplicaDescriptor{
NodeID: newStore.Node.NodeID,
StoreID: newStore.StoreID,
}
log.VTracef(1, ctx, "%s: adding replica to %+v due to under-replication", repl, newReplica)
if err = repl.ChangeReplicas(ctx, roachpb.ADD_REPLICA, newReplica, desc); err != nil {
return err
}
case AllocatorRemove:
log.Trace(ctx, "removing a replica")
// We require the lease in order to process replicas, so
// repl.store.StoreID() corresponds to the lease-holder's store ID.
removeReplica, err := rq.allocator.RemoveTarget(desc.Replicas, repl.store.StoreID())
if err != nil {
return err
}
log.VTracef(1, ctx, "%s: removing replica %+v due to over-replication", repl, removeReplica)
if err = repl.ChangeReplicas(ctx, roachpb.REMOVE_REPLICA, removeReplica, desc); err != nil {
return err
}
// Do not requeue if we removed ourselves.
if removeReplica.StoreID == repl.store.StoreID() {
return nil
}
case AllocatorRemoveDead:
log.Trace(ctx, "removing a dead replica")
if len(deadReplicas) == 0 {
if log.V(1) {
log.Warningf(ctx, "Range of replica %s was identified as having dead replicas, but no dead replicas were found.", repl)
}
break
}
deadReplica := deadReplicas[0]
log.VTracef(1, ctx, "%s: removing dead replica %+v from store", repl, deadReplica)
if err = repl.ChangeReplicas(ctx, roachpb.REMOVE_REPLICA, deadReplica, desc); err != nil {
return err
}
case AllocatorNoop:
log.Trace(ctx, "considering a rebalance")
// The Noop case will result if this replica was queued in order to
// rebalance. Attempt to find a rebalancing target.
//
// We require the lease in order to process replicas, so
// repl.store.StoreID() corresponds to the lease-holder's store ID.
rebalanceStore := rq.allocator.RebalanceTarget(
zone.ReplicaAttrs[0], desc.Replicas, repl.store.StoreID())
if rebalanceStore == nil {
log.VTracef(1, ctx, "%s: no suitable rebalance target", repl)
// No action was necessary and no rebalance target was found. Return
// without re-queuing this replica.
return nil
}
rebalanceReplica := roachpb.ReplicaDescriptor{
NodeID: rebalanceStore.Node.NodeID,
StoreID: rebalanceStore.StoreID,
}
log.VTracef(1, ctx, "%s: rebalancing to %+v", repl, rebalanceReplica)
if err = repl.ChangeReplicas(ctx, roachpb.ADD_REPLICA, rebalanceReplica, desc); err != nil {
return err
}
}
// Enqueue this replica again to see if there are more changes to be made.
rq.MaybeAdd(repl, rq.clock.Now())
return nil
}
// sendChunk is in charge of sending an "admissible" piece of batch, i.e. one
// which doesn't need to be subdivided further before going to a range (so no
// mixing of forward and reverse scans, etc). The parameters and return values
// correspond to client.Sender with the exception of the returned boolean,
// which is true when indicating that the caller should retry but needs to send
// EndTransaction in a separate request.
func (ds *DistSender) sendChunk(ctx context.Context, ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error, bool) {
isReverse := ba.IsReverse()
// TODO(radu): when contexts are properly plumbed, we should be able to get
// the tracer from ctx, not from the DistSender.
ctx, cleanup := tracing.EnsureContext(ctx, tracing.TracerFromCtx(ds.Ctx))
defer cleanup()
// The minimal key range encompassing all requests contained within.
// Local addressing has already been resolved.
// TODO(tschottdorf): consider rudimentary validation of the batch here
// (for example, non-range requests with EndKey, or empty key ranges).
rs, err := keys.Range(ba)
if err != nil {
return nil, roachpb.NewError(err), false
}
var br *roachpb.BatchResponse
// Send the request to one range per iteration.
for {
// Increase the sequence counter only once before sending RPCs to
// the ranges involved in this chunk of the batch (as opposed to for
// each RPC individually). On RPC errors, there's no guarantee that
// the request hasn't made its way to the target regardless of the
// error; we'd like the second execution to be caught by the sequence
// cache if that happens. There is a small chance that that we address
// a range twice in this chunk (stale/suboptimal descriptors due to
// splits/merges) which leads to a transaction retry.
// TODO(tschottdorf): it's possible that if we don't evict from the
// cache we could be in for a busy loop.
ba.SetNewRequest()
var curReply *roachpb.BatchResponse
var desc *roachpb.RangeDescriptor
var evictToken *evictionToken
var needAnother bool
var pErr *roachpb.Error
var finished bool
var numAttempts int
for r := retry.StartWithCtx(ctx, ds.rpcRetryOptions); r.Next(); {
numAttempts++
{
const magicLogCurAttempt = 20
var seq int32
if ba.Txn != nil {
seq = ba.Txn.Sequence
}
if numAttempts%magicLogCurAttempt == 0 || seq%magicLogCurAttempt == 0 {
// Log a message if a request appears to get stuck for a long
// time or, potentially, forever. See #8975.
// The local counter captures this loop here; the Sequence number
// should capture anything higher up (as it needs to be
// incremented every time this method is called).
log.Warningf(
ctx,
"%d retries for an RPC at sequence %d, last error was: %s, remaining key ranges %s: %s",
numAttempts, seq, pErr, rs, ba,
)
}
}
// Get range descriptor (or, when spanning range, descriptors). Our
// error handling below may clear them on certain errors, so we
// refresh (likely from the cache) on every retry.
log.Trace(ctx, "meta descriptor lookup")
var err error
desc, needAnother, evictToken, err = ds.getDescriptors(ctx, rs, evictToken, isReverse)
// getDescriptors may fail retryably if, for example, the first
// range isn't available via Gossip. Assume that all errors at
// this level are retryable. Non-retryable errors would be for
// things like malformed requests which we should have checked
// for before reaching this point.
if err != nil {
log.Trace(ctx, "range descriptor lookup failed: "+err.Error())
if log.V(1) {
log.Warning(ctx, err)
}
pErr = roachpb.NewError(err)
continue
}
if needAnother && br == nil {
// TODO(tschottdorf): we should have a mechanism for discovering
// range merges (descriptor staleness will mostly go unnoticed),
// or we'll be turning single-range queries into multi-range
// queries for no good reason.
// If there's no transaction and op spans ranges, possibly
// re-run as part of a transaction for consistency. The
// case where we don't need to re-run is if the read
// consistency is not required.
if ba.Txn == nil && ba.IsPossibleTransaction() &&
ba.ReadConsistency != roachpb.INCONSISTENT {
return nil, roachpb.NewError(&roachpb.OpRequiresTxnError{}), false
}
// If the request is more than but ends with EndTransaction, we
// want the caller to come again with the EndTransaction in an
// extra call.
if l := len(ba.Requests) - 1; l > 0 && ba.Requests[l].GetInner().Method() == roachpb.EndTransaction {
return nil, roachpb.NewError(errors.New("cannot send 1PC txn to multiple ranges")), true /* shouldSplitET */
}
}
// It's possible that the returned descriptor misses parts of the
// keys it's supposed to scan after it's truncated to match the
// descriptor. Example revscan [a,g), first desc lookup for "g"
// returns descriptor [c,d) -> [d,g) is never scanned.
// We evict and retry in such a case.
includesFrontOfCurSpan := func(rd *roachpb.RangeDescriptor) bool {
if isReverse {
return desc.ContainsExclusiveEndKey(rs.EndKey)
}
return desc.ContainsKey(rs.Key)
}
if !includesFrontOfCurSpan(desc) {
if err := evictToken.Evict(ctx); err != nil {
return nil, roachpb.NewError(err), false
}
// On addressing errors, don't backoff; retry immediately.
r.Reset()
continue
}
curReply, pErr = func() (*roachpb.BatchResponse, *roachpb.Error) {
// Truncate the request to our current key range.
intersected, iErr := rs.Intersect(desc)
if iErr != nil {
return nil, roachpb.NewError(iErr)
}
truncBA, numActive, trErr := truncate(ba, intersected)
if numActive == 0 && trErr == nil {
// This shouldn't happen in the wild, but some tests
// exercise it.
return nil, roachpb.NewErrorf("truncation resulted in empty batch on [%s,%s): %s",
rs.Key, rs.EndKey, ba)
}
if trErr != nil {
return nil, roachpb.NewError(trErr)
}
return ds.sendSingleRange(ctx, truncBA, desc)
}()
// If sending succeeded, break this loop.
if pErr == nil {
finished = true
break
}
log.VTracef(1, ctx, "reply error %s: %s", ba, pErr)
// Error handling: If the error indicates that our range
// descriptor is out of date, evict it from the cache and try
// again. Errors that apply only to a single replica were
// handled in send().
//
// TODO(bdarnell): Don't retry endlessly. If we fail twice in a
// row and the range descriptor hasn't changed, return the error
// to our caller.
switch tErr := pErr.GetDetail().(type) {
case *roachpb.SendError:
// We've tried all the replicas without success. Either
// they're all down, or we're using an out-of-date range
// descriptor. Invalidate the cache and try again with the new
// metadata.
if err := evictToken.Evict(ctx); err != nil {
return nil, roachpb.NewError(err), false
}
continue
case *roachpb.RangeKeyMismatchError:
// Range descriptor might be out of date - evict it. This is
// likely the result of a range split. If we have new range
// descriptors, insert them instead as long as they are different
// from the last descriptor to avoid endless loops.
var replacements []roachpb.RangeDescriptor
different := func(rd *roachpb.RangeDescriptor) bool {
return !desc.RSpan().Equal(rd.RSpan())
}
if tErr.MismatchedRange != nil && different(tErr.MismatchedRange) {
replacements = append(replacements, *tErr.MismatchedRange)
}
if tErr.SuggestedRange != nil && different(tErr.SuggestedRange) {
if includesFrontOfCurSpan(tErr.SuggestedRange) {
replacements = append(replacements, *tErr.SuggestedRange)
}
}
// Same as Evict() if replacements is empty.
if err := evictToken.EvictAndReplace(ctx, replacements...); err != nil {
return nil, roachpb.NewError(err), false
}
// On addressing errors, don't backoff; retry immediately.
r.Reset()
if log.V(1) {
log.Warning(ctx, tErr)
}
continue
}
break
}
// Immediately return if querying a range failed non-retryably.
if pErr != nil {
return nil, pErr, false
} else if !finished {
select {
case <-ds.rpcRetryOptions.Closer:
return nil, roachpb.NewError(&roachpb.NodeUnavailableError{}), false
case <-ctx.Done():
return nil, roachpb.NewError(ctx.Err()), false
default:
log.Fatal(ctx, "exited retry loop with nil error but finished=false")
}
}
ba.UpdateTxn(curReply.Txn)
if br == nil {
// First response from a Range.
br = curReply
} else {
// This was the second or later call in a cross-Range request.
// Combine the new response with the existing one.
if err := br.Combine(curReply); err != nil {
return nil, roachpb.NewError(err), false
}
}
if isReverse {
// In next iteration, query previous range.
// We use the StartKey of the current descriptor as opposed to the
// EndKey of the previous one since that doesn't have bugs when
// stale descriptors come into play.
rs.EndKey, err = prev(ba, desc.StartKey)
} else {
// In next iteration, query next range.
// It's important that we use the EndKey of the current descriptor
// as opposed to the StartKey of the next one: if the former is stale,
// it's possible that the next range has since merged the subsequent
// one, and unless both descriptors are stale, the next descriptor's
// StartKey would move us to the beginning of the current range,
// resulting in a duplicate scan.
rs.Key, err = next(ba, desc.EndKey)
}
if err != nil {
return nil, roachpb.NewError(err), false
}
if ba.MaxSpanRequestKeys > 0 {
// Count how many results we received.
var numResults int64
for _, resp := range curReply.Responses {
numResults += resp.GetInner().Header().NumKeys
}
if numResults > ba.MaxSpanRequestKeys {
panic(fmt.Sprintf("received %d results, limit was %d", numResults, ba.MaxSpanRequestKeys))
}
ba.MaxSpanRequestKeys -= numResults
if ba.MaxSpanRequestKeys == 0 {
// prepare the batch response after meeting the max key limit.
fillSkippedResponses(ba, br, rs)
// done, exit loop.
return br, nil, false
}
}
// If this was the last range accessed by this call, exit loop.
if !needAnother {
return br, nil, false
}
// key cannot be less that the end key.
if !rs.Key.Less(rs.EndKey) {
panic(fmt.Sprintf("start key %s is less than %s", rs.Key, rs.EndKey))
}
log.Trace(ctx, "querying next range")
}
}
// process performs a consistent lookup on the range descriptor to see if we are
// still a member of the range.
func (q *replicaGCQueue) process(
ctx context.Context,
now hlc.Timestamp,
rng *Replica,
_ config.SystemConfig,
) error {
// Note that the Replicas field of desc is probably out of date, so
// we should only use `desc` for its static fields like RangeID and
// StartKey (and avoid rng.GetReplica() for the same reason).
desc := rng.Desc()
// Calls to RangeLookup typically use inconsistent reads, but we
// want to do a consistent read here. This is important when we are
// considering one of the metadata ranges: we must not do an
// inconsistent lookup in our own copy of the range.
b := &client.Batch{}
b.AddRawRequest(&roachpb.RangeLookupRequest{
Span: roachpb.Span{
Key: keys.RangeMetaKey(desc.StartKey),
},
MaxRanges: 1,
})
if err := q.db.Run(b); err != nil {
return err
}
br := b.RawResponse()
reply := br.Responses[0].GetInner().(*roachpb.RangeLookupResponse)
if len(reply.Ranges) != 1 {
return errors.Errorf("expected 1 range descriptor, got %d", len(reply.Ranges))
}
replyDesc := reply.Ranges[0]
if _, currentMember := replyDesc.GetReplicaDescriptor(rng.store.StoreID()); !currentMember {
// We are no longer a member of this range; clean up our local data.
if log.V(1) {
log.Infof("destroying local data from range %d", desc.RangeID)
}
log.Trace(ctx, "destroying local data")
if err := rng.store.RemoveReplica(rng, replyDesc, true); err != nil {
return err
}
} else if desc.RangeID != replyDesc.RangeID {
// If we get a different range ID back, then the range has been merged
// away. But currentMember is true, so we are still a member of the
// subsuming range. Shut down raft processing for the former range
// and delete any remaining metadata, but do not delete the data.
if log.V(1) {
log.Infof("removing merged range %d", desc.RangeID)
}
log.Trace(ctx, "removing merged range")
if err := rng.store.RemoveReplica(rng, replyDesc, false); err != nil {
return err
}
// TODO(bdarnell): remove raft logs and other metadata (while leaving a
// tombstone). Add tests for GC of merged ranges.
} else {
// This replica is a current member of the raft group. Set the last replica
// GC check time to avoid re-processing for another check interval.
if err := rng.setLastReplicaGCTimestamp(now); err != nil {
return err
}
}
return nil
}
