Golang BatchRequest.MaxScanResults方法代码示例

// send runs the specified calls synchronously in a single batch and returns
// any errors. Returns a nil response for empty input (no requests).
func (db *DB) send(maxScanResults int64, readConsistency roachpb.ReadConsistencyType,
	reqs ...roachpb.Request) (*roachpb.BatchResponse, *roachpb.Error) {
	if len(reqs) == 0 {
		return nil, nil
	}

	if readConsistency == roachpb.INCONSISTENT {
		for _, req := range reqs {
			if req.Method() != roachpb.Get && req.Method() != roachpb.Scan &&
				req.Method() != roachpb.ReverseScan {
				return nil, roachpb.NewErrorf("method %s not allowed with INCONSISTENT batch", req.Method)
			}
		}
	}

	ba := roachpb.BatchRequest{}
	ba.Add(reqs...)

	ba.MaxScanResults = maxScanResults
	if db.userPriority != 1 {
		ba.UserPriority = db.userPriority
	}
	ba.ReadConsistency = readConsistency

	tracing.AnnotateTrace()

	br, pErr := db.sender.Send(context.TODO(), ba)
	if pErr != nil {
		if log.V(1) {
			log.Infof("failed batch: %s", pErr)
		}
		return nil, pErr
	}
	return br, nil
}

// send runs the specified calls synchronously in a single batch and returns
// any errors. Returns a nil response for empty input (no requests).
func (db *DB) send(maxScanResults int64, reqs ...roachpb.Request) (
	*roachpb.BatchResponse, *roachpb.Error) {
	if len(reqs) == 0 {
		return nil, nil
	}

	ba := roachpb.BatchRequest{}
	ba.Add(reqs...)

	ba.MaxScanResults = maxScanResults
	if db.userPriority != 1 {
		ba.UserPriority = db.userPriority
	}

	tracing.AnnotateTrace()

	br, pErr := db.sender.Send(context.TODO(), ba)
	if pErr != nil {
		if log.V(1) {
			log.Infof("failed batch: %s", pErr)
		}
		return nil, pErr
	}
	return br, nil
}

//.........这里部分代码省略.........
						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
			}
		}