// 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
}
