Method MovePredicate

worker/predicate_move.go:189–255

(ctx context.Context,
	in *pb.MovePredicatePayload)

}

func (w *grpcWorker) MovePredicate(ctx context.Context,
	in *pb.MovePredicatePayload) (*api.Payload, error) {
	ctx, span := trace.SpanFromContext(ctx).TracerProvider().Tracer("grpcWorker").Start(ctx, "MovePredicate")
	defer span.End()

	n := groups().Node
	if !n.AmLeader() {
		return &emptyPayload, errNotLeader
	}
	// Don't do a predicate move if the cluster is in draining mode.
	if err := x.HealthCheck(); err != nil {
		return &emptyPayload, errors.Wrap(err, "Move predicate request rejected")
	}

	if groups().groupId() != in.SourceGid {
		return &emptyPayload,
			errors.Errorf("Group id doesn't match, received request for %d, my gid: %d",
				in.SourceGid, groups().groupId())
	}
	if len(in.Predicate) == 0 {
		return &emptyPayload, errEmptyPredicate
	}

	//TODO: need to find possibly a better way to not move __vector_ predicates
	if in.DestGid == 0 && !strings.Contains(in.Predicate, hnsw.VecKeyword) {
		glog.Infof("Was instructed to delete tablet: %v", in.Predicate)
		// Expected Checksum ensures that all the members of this group would block until they get
		// the latest membership status where this predicate now belongs to another group. So they
		// know that they are no longer serving this predicate, before they delete it from their
		// state. Without this checksum, the members could end up deleting the predicate and then
		// serve a request asking for that predicate, causing Jepsen failures.
		p := &pb.Proposal{
			CleanPredicate:   in.Predicate,
			ExpectedChecksum: in.ExpectedChecksum,
			StartTs:          in.TxnTs,
		}
		return &emptyPayload, groups().Node.proposeAndWait(ctx, p)
	}

	if strings.Contains(in.Predicate, hnsw.VecKeyword) {
		return &emptyPayload, nil
	}

	if err := posting.Oracle().WaitForTs(ctx, in.TxnTs); err != nil {
		return &emptyPayload, errors.Errorf("While waiting for txn ts: %d. Error: %v", in.TxnTs, err)
	}

	gid, err := groups().BelongsTo(in.Predicate)
	switch {
	case err != nil:
		return &emptyPayload, err
	case gid == 0:
		return &emptyPayload, errNonExistentTablet
	case gid != groups().groupId():
		return &emptyPayload, errUnservedTablet
	}

	msg := fmt.Sprintf("Move predicate request: %+v", in)