// loadState loads a ReplicaState from disk. The exception is the Desc field,
// which is updated transactionally, and is populated from the supplied
// RangeDescriptor under the convention that that is the latest committed
// version.
func loadState(
ctx context.Context, reader engine.Reader, desc *roachpb.RangeDescriptor,
) (storagebase.ReplicaState, error) {
var s storagebase.ReplicaState
// TODO(tschottdorf): figure out whether this is always synchronous with
// on-disk state (likely iffy during Split/ChangeReplica triggers).
s.Desc = protoutil.Clone(desc).(*roachpb.RangeDescriptor)
// Read the range lease.
lease, err := loadLease(ctx, reader, desc.RangeID)
if err != nil {
return storagebase.ReplicaState{}, err
}
s.Lease = &lease
if s.Frozen, err = loadFrozenStatus(ctx, reader, desc.RangeID); err != nil {
return storagebase.ReplicaState{}, err
}
if s.GCThreshold, err = loadGCThreshold(ctx, reader, desc.RangeID); err != nil {
return storagebase.ReplicaState{}, err
}
if s.TxnSpanGCThreshold, err = loadTxnSpanGCThreshold(ctx, reader, desc.RangeID); err != nil {
return storagebase.ReplicaState{}, err
}
if s.RaftAppliedIndex, s.LeaseAppliedIndex, err = loadAppliedIndex(
ctx, reader, desc.RangeID,
); err != nil {
return storagebase.ReplicaState{}, err
}
if s.Stats, err = loadMVCCStats(ctx, reader, desc.RangeID); err != nil {
return storagebase.ReplicaState{}, err
}
// The truncated state should not be optional (i.e. the pointer is
// pointless), but it is and the migration is not worth it.
truncState, err := loadTruncatedState(ctx, reader, desc.RangeID)
if err != nil {
return storagebase.ReplicaState{}, err
}
s.TruncatedState = &truncState
return s, nil
}
// writeInitialState bootstraps a new Raft group (i.e. it is called when we
// bootstrap a Range, or when setting up the right hand side of a split).
// Its main task is to persist a consistent Raft (and associated Replica) state
// which does not start from zero but presupposes a few entries already having
// applied.
// The supplied MVCCStats are used for the Stats field after adjusting for
// persisting the state itself, and the updated stats are returned.
func writeInitialState(
ctx context.Context,
eng engine.ReadWriter,
ms enginepb.MVCCStats,
desc roachpb.RangeDescriptor,
oldHS raftpb.HardState,
lease *roachpb.Lease,
) (enginepb.MVCCStats, error) {
var s storagebase.ReplicaState
s.TruncatedState = &roachpb.RaftTruncatedState{
Term: raftInitialLogTerm,
Index: raftInitialLogIndex,
}
s.RaftAppliedIndex = s.TruncatedState.Index
s.Desc = &roachpb.RangeDescriptor{
RangeID: desc.RangeID,
}
s.Frozen = storagebase.ReplicaState_UNFROZEN
s.Stats = ms
s.Lease = lease
if existingLease, err := loadLease(ctx, eng, desc.RangeID); err != nil {
return enginepb.MVCCStats{}, errors.Wrap(err, "error reading lease")
} else if (existingLease != roachpb.Lease{}) {
log.Fatalf(ctx, "expected trivial lease, but found %+v", existingLease)
}
newMS, err := saveState(ctx, eng, s)
if err != nil {
return enginepb.MVCCStats{}, err
}
if err := synthesizeHardState(ctx, eng, s, oldHS); err != nil {
return enginepb.MVCCStats{}, err
}
if err := setLastIndex(ctx, eng, desc.RangeID, s.TruncatedState.Index); err != nil {
return enginepb.MVCCStats{}, err
}
return newMS, nil
}