Exemplo n.º 1
0
// Scan retrieves the values specified in families from the given range.
func (c *Client) Scan(s *hrpc.Scan) ([]*pb.Result, error) {
	var results []*pb.Result
	var scanres *pb.ScanResponse
	var rpc *hrpc.Scan
	ctx := s.GetContext()
	table := s.Table()
	families := s.GetFamilies()
	filters := s.GetFilter()
	startRow := s.GetStartRow()
	stopRow := s.GetStopRow()
	for {
		// Make a new Scan RPC for this region
		if rpc == nil {
			// If it's the first region, just begin at the given startRow
			rpc, _ = hrpc.NewScanRange(ctx, table, startRow, stopRow, hrpc.Families(families), hrpc.Filters(filters))
		} else {
			// If it's not the first region, we want to start at whatever the
			// last region's StopKey was
			rpc, _ = hrpc.NewScanRange(ctx, table, rpc.GetRegionStop(), stopRow, hrpc.Families(families), hrpc.Filters(filters))
		}

		res, err := c.sendRPC(rpc)
		if err != nil {
			return nil, err
		}
		scanres = res.(*pb.ScanResponse)
		results = append(results, scanres.Results...)

		// TODO: The more_results field of the ScanResponse object was always
		// true, so we should figure out if there's a better way to know when
		// to move on to the next region than making an extra request and
		// seeing if there were no results
		for len(scanres.Results) != 0 {
			rpc = hrpc.NewScanFromID(ctx, table, *scanres.ScannerId, rpc.Key())

			res, err = c.sendRPC(rpc)
			if err != nil {
				return nil, err
			}
			scanres = res.(*pb.ScanResponse)
			results = append(results, scanres.Results...)
		}

		rpc = hrpc.NewCloseFromID(ctx, table, *scanres.ScannerId, rpc.Key())
		if err != nil {
			return nil, err
		}
		res, err = c.sendRPC(rpc)

		// Check to see if this region is the last we should scan (either
		// because (1) it's the last region or (3) because its stop_key is
		// greater than or equal to the stop_key of this scanner provided
		// that (2) we're not trying to scan until the end of the table).
		// (1)                               (2)                  (3)
		if len(rpc.GetRegionStop()) == 0 || (len(stopRow) != 0 && bytes.Compare(stopRow, rpc.GetRegionStop()) <= 0) {
			return results, nil
		}
	}
}
Exemplo n.º 2
0
// Scan retrieves the values specified in families from the given range.
func (c *client) Scan(s *hrpc.Scan) ([]*hrpc.Result, error) {
	var results []*pb.Result
	var scanres *pb.ScanResponse
	var rpc *hrpc.Scan
	ctx := s.Context()
	table := s.Table()
	families := s.Families()
	filters := s.Filter()
	startRow := s.StartRow()
	stopRow := s.StopRow()
	fromTs, toTs := s.TimeRange()
	maxVerions := s.MaxVersions()
	numberOfRows := s.NumberOfRows()
	for {
		// Make a new Scan RPC for this region
		if rpc != nil {
			// If it's not the first region, we want to start at whatever the
			// last region's StopKey was
			startRow = rpc.RegionStop()
		}

		// TODO: would be nicer to clone it in some way
		rpc, err := hrpc.NewScanRange(ctx, table, startRow, stopRow,
			hrpc.Families(families), hrpc.Filters(filters),
			hrpc.TimeRangeUint64(fromTs, toTs),
			hrpc.MaxVersions(maxVerions),
			hrpc.NumberOfRows(numberOfRows))
		if err != nil {
			return nil, err
		}

		res, err := c.sendRPC(rpc)
		if err != nil {
			return nil, err
		}
		scanres = res.(*pb.ScanResponse)
		results = append(results, scanres.Results...)

		// TODO: The more_results field of the ScanResponse object was always
		// true, so we should figure out if there's a better way to know when
		// to move on to the next region than making an extra request and
		// seeing if there were no results
		for len(scanres.Results) != 0 {
			rpc = hrpc.NewScanFromID(ctx, table, *scanres.ScannerId, rpc.Key())

			res, err = c.sendRPC(rpc)
			if err != nil {
				return nil, err
			}
			scanres = res.(*pb.ScanResponse)
			results = append(results, scanres.Results...)
		}

		rpc = hrpc.NewCloseFromID(ctx, table, *scanres.ScannerId, rpc.Key())
		if err != nil {
			return nil, err
		}
		res, err = c.sendRPC(rpc)

		// Check to see if this region is the last we should scan (either
		// because (1) it's the last region or (3) because its stop_key is
		// greater than or equal to the stop_key of this scanner provided
		// that (2) we're not trying to scan until the end of the table).
		// (1)
		if len(rpc.RegionStop()) == 0 ||
			// (2)                (3)
			len(stopRow) != 0 && bytes.Compare(stopRow, rpc.RegionStop()) <= 0 {
			// Do we want to be returning a slice of Result objects or should we just
			// put all the Cells into the same Result object?
			localResults := make([]*hrpc.Result, len(results))
			for idx, result := range results {
				localResults[idx] = hrpc.ToLocalResult(result)
			}
			return localResults, nil
		}
	}
}