Golang BatchRequest.IsReadOnly Examples

Example #1

File: dist_sender.go Project: knz/cockroach

// 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) {
	// 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.
	ds.optimizeReplicaOrder(replicas)

	// If this request needs to go to a lease holder and we know who that is, move
	// it to the front.
	if !(ba.IsReadOnly() && ba.ReadConsistency == roachpb.INCONSISTENT) {
		if leaseHolder, ok := ds.leaseHolderCache.Lookup(ctx, desc.RangeID); ok {
			if i := replicas.FindReplica(leaseHolder.StoreID); i >= 0 {
				replicas.MoveToFront(i)
			}
		}
	}

	// TODO(tschottdorf): should serialize the trace here, not higher up.
	br, err := ds.sendRPC(ctx, desc.RangeID, replicas, ba)
	if err != nil {
		return nil, roachpb.NewError(err)
	}

	// If the reply contains a timestamp, update the local HLC with it.
	if br.Error != nil && br.Error.Now != hlc.ZeroTimestamp {
		ds.clock.Update(br.Error.Now)
	} else if br.Now != hlc.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
}