示例#1
0
文件: index.go 项目: anywhy/tidb
func (c *index) Exist(rm kv.RetrieverMutator, indexedValues []types.Datum, h int64) (bool, int64, error) {
	key, distinct, err := c.GenIndexKey(indexedValues, h)
	if err != nil {
		return false, 0, errors.Trace(err)
	}

	value, err := rm.Get(key)
	if kv.IsErrNotFound(err) {
		return false, 0, nil
	}
	if err != nil {
		return false, 0, errors.Trace(err)
	}

	// For distinct index, the value of key is handle.
	if distinct {
		handle, err := decodeHandle(value)
		if err != nil {
			return false, 0, errors.Trace(err)
		}

		if handle != h {
			return true, handle, errors.Trace(kv.ErrKeyExists)
		}

		return true, handle, nil
	}

	return true, h, nil
}
示例#2
0
文件: index.go 项目: anywhy/tidb
// Create creates a new entry in the kvIndex data.
// If the index is unique and there is an existing entry with the same key, Create will return ErrKeyExists.
func (c *index) Create(rm kv.RetrieverMutator, indexedValues []types.Datum, h int64) error {
	key, distinct, err := c.GenIndexKey(indexedValues, h)
	if err != nil {
		return errors.Trace(err)
	}
	if !distinct {
		// TODO: reconsider value
		err = rm.Set(key, []byte("timestamp?"))
		return errors.Trace(err)
	}

	_, err = rm.Get(key)
	if kv.IsErrNotFound(err) {
		err = rm.Set(key, encodeHandle(h))
		return errors.Trace(err)
	}

	return errors.Trace(kv.ErrKeyExists)
}
示例#3
0
文件: index.go 项目: pingcap/tidb
// Create creates a new entry in the kvIndex data.
// If the index is unique and there is an existing entry with the same key,
// Create will return the existing entry's handle as the first return value, ErrKeyExists as the second return value.
func (c *index) Create(rm kv.RetrieverMutator, indexedValues []types.Datum, h int64) (int64, error) {
	key, distinct, err := c.GenIndexKey(indexedValues, h)
	if err != nil {
		return 0, errors.Trace(err)
	}
	if !distinct {
		// non-unique index doesn't need store value, write a '0' to reduce space
		err = rm.Set(key, []byte{'0'})
		return 0, errors.Trace(err)
	}

	value, err := rm.Get(key)
	if kv.IsErrNotFound(err) {
		err = rm.Set(key, encodeHandle(h))
		return 0, errors.Trace(err)
	}
	handle, err := decodeHandle(value)
	if err != nil {
		return 0, errors.Trace(err)
	}
	return handle, errors.Trace(kv.ErrKeyExists)
}