Пример #1
0
func encodeStartConstraintDescending(spans []roachpb.Span, c *parser.ComparisonExpr) {
	switch c.Operator {
	case parser.Is:
		// An IS NULL expressions allows us to constrain the start of the range
		// to begin at NULL.
		if c.Right != parser.DNull {
			panic(fmt.Sprintf("expected NULL operand for IS operator, found %v", c.Right))
		}
		for i := range spans {
			spans[i].Key = encoding.EncodeNullDescending(spans[i].Key)
		}
	case parser.NE:
		panic("'!=' operators should have been transformed to 'IS NOT NULL'")
	case parser.LE, parser.EQ:
		datum := c.Right.(parser.Datum)
		key, err := sqlbase.EncodeTableKey(nil, datum, encoding.Descending)
		if err != nil {
			panic(err)
		}
		// Append the constraint to all of the existing spans.
		for i := range spans {
			spans[i].Key = append(spans[i].Key, key...)
		}
	case parser.LT:
		// A "<" constraint is the last start constraint. Since the constraint
		// is exclusive and the start key is inclusive, we're going to apply
		// a .PrefixEnd(). Note that a "<" is usually transformed to a "<=".
		datum := c.Right.(parser.Datum)
		key, err := sqlbase.EncodeTableKey(nil, datum, encoding.Descending)
		if err != nil {
			panic(err)
		}
		// Append the constraint to all of the existing spans.
		for i := range spans {
			spans[i].Key = append(spans[i].Key, key...)
			spans[i].Key = spans[i].Key.PrefixEnd()
		}

	default:
		panic(fmt.Sprintf("unexpected operator: %s", c))
	}
}
Пример #2
0
// EncodeTableKey encodes `val` into `b` and returns the new buffer.
func EncodeTableKey(b []byte, val parser.Datum, dir encoding.Direction) ([]byte, error) {
	if (dir != encoding.Ascending) && (dir != encoding.Descending) {
		return nil, errors.Errorf("invalid direction: %d", dir)
	}

	if val == parser.DNull {
		if dir == encoding.Ascending {
			return encoding.EncodeNullAscending(b), nil
		}
		return encoding.EncodeNullDescending(b), nil
	}

	switch t := val.(type) {
	case *parser.DBool:
		var x int64
		if *t {
			x = 1
		} else {
			x = 0
		}
		if dir == encoding.Ascending {
			return encoding.EncodeVarintAscending(b, x), nil
		}
		return encoding.EncodeVarintDescending(b, x), nil
	case *parser.DInt:
		if dir == encoding.Ascending {
			return encoding.EncodeVarintAscending(b, int64(*t)), nil
		}
		return encoding.EncodeVarintDescending(b, int64(*t)), nil
	case *parser.DFloat:
		if dir == encoding.Ascending {
			return encoding.EncodeFloatAscending(b, float64(*t)), nil
		}
		return encoding.EncodeFloatDescending(b, float64(*t)), nil
	case *parser.DDecimal:
		if dir == encoding.Ascending {
			return encoding.EncodeDecimalAscending(b, &t.Dec), nil
		}
		return encoding.EncodeDecimalDescending(b, &t.Dec), nil
	case *parser.DString:
		if dir == encoding.Ascending {
			return encoding.EncodeStringAscending(b, string(*t)), nil
		}
		return encoding.EncodeStringDescending(b, string(*t)), nil
	case *parser.DBytes:
		if dir == encoding.Ascending {
			return encoding.EncodeStringAscending(b, string(*t)), nil
		}
		return encoding.EncodeStringDescending(b, string(*t)), nil
	case *parser.DDate:
		if dir == encoding.Ascending {
			return encoding.EncodeVarintAscending(b, int64(*t)), nil
		}
		return encoding.EncodeVarintDescending(b, int64(*t)), nil
	case *parser.DTimestamp:
		if dir == encoding.Ascending {
			return encoding.EncodeTimeAscending(b, t.Time), nil
		}
		return encoding.EncodeTimeDescending(b, t.Time), nil
	case *parser.DTimestampTZ:
		if dir == encoding.Ascending {
			return encoding.EncodeTimeAscending(b, t.Time), nil
		}
		return encoding.EncodeTimeDescending(b, t.Time), nil
	case *parser.DInterval:
		if dir == encoding.Ascending {
			return encoding.EncodeDurationAscending(b, t.Duration)
		}
		return encoding.EncodeDurationDescending(b, t.Duration)
	case *parser.DTuple:
		for _, datum := range *t {
			var err error
			b, err = EncodeTableKey(b, datum, dir)
			if err != nil {
				return nil, err
			}
		}
		return b, nil
	}
	return nil, errors.Errorf("unable to encode table key: %T", val)
}