示例#1
0
// queryRows implements the queryRunner interface.
func (p *planner) queryRows(sql string, args ...interface{}) ([]parser.DTuple, error) {
	plan, err := p.query(sql, args...)
	if err != nil {
		return nil, err
	}
	defer plan.Close()
	if err := plan.Start(); err != nil {
		return nil, err
	}
	if next, err := plan.Next(); err != nil || !next {
		return nil, err
	}

	var rows []parser.DTuple
	for {
		if values := plan.Values(); values != nil {
			valCopy := append(parser.DTuple(nil), values...)
			rows = append(rows, valCopy)
		}

		next, err := plan.Next()
		if err != nil {
			return nil, err
		}
		if !next {
			break
		}
	}
	return rows, nil
}
示例#2
0
package sql

import (
	"fmt"
	"unsafe"

	"github.com/cockroachdb/cockroach/pkg/sql/mon"
	"github.com/cockroachdb/cockroach/pkg/sql/parser"
)

const (
	// targetChunkSize is the target number of Datums in a RowContainer chunk.
	targetChunkSize = 64
	sizeOfDatum     = int64(unsafe.Sizeof(parser.Datum(nil)))
	sizeOfDTuple    = int64(unsafe.Sizeof(parser.DTuple(nil)))
)

// RowContainer is a container for rows of DTuples which tracks the
// approximate amount of memory allocated for row data.
// Rows must be added using AddRow(); once the work is done
// the Close() method must be called to release the allocated memory.
//
// TODO(knz): this does not currently track the amount of memory used
// for the outer array of DTuple references.
type RowContainer struct {
	numCols int

	// rowsPerChunk is the number of rows in a chunk; we pack multiple rows in a
	// single []Datum to reduce the overhead of the slice if we have few columns.
	rowsPerChunk int