Golang Transaction.Get方法代碼示例

func mustNotGet(c *C, txn kv.Transaction) {
	for i := startIndex; i < testCount; i++ {
		s := encodeInt(i * indexStep)
		_, err := txn.Get(s)
		c.Assert(err, NotNil)
	}
}

func fetchRowColVals(txn kv.Transaction, t table.Table, handle int64, indexInfo *model.IndexInfo) (
	kv.Key, []types.Datum, error) {
	// fetch datas
	cols := t.Cols()
	colMap := make(map[int64]*types.FieldType)
	for _, v := range indexInfo.Columns {
		col := cols[v.Offset]
		colMap[col.ID] = &col.FieldType
	}
	rowKey := tablecodec.EncodeRecordKey(t.RecordPrefix(), handle)
	rowVal, err := txn.Get(rowKey)
	if err != nil {
		return nil, nil, errors.Trace(err)
	}
	row, err := tablecodec.DecodeRow(rowVal, colMap)
	if err != nil {
		return nil, nil, errors.Trace(err)
	}
	vals := make([]types.Datum, 0, len(indexInfo.Columns))
	for _, v := range indexInfo.Columns {
		col := cols[v.Offset]
		vals = append(vals, row[col.ID])
	}
	return rowKey, vals, nil
}

func mustGet(c *C, txn kv.Transaction) {
	for i := startIndex; i < testCount; i++ {
		s := encodeInt(i * indexStep)
		val, err := txn.Get(s)
		c.Assert(err, IsNil)
		c.Assert(string(val), Equals, string(s))
	}
}

func checkRowExist(txn kv.Transaction, t table.Table, handle int64) (bool, error) {
	_, err := txn.Get(t.RecordKey(handle, nil))
	if terror.ErrorEqual(err, kv.ErrNotExist) {
		// If row doesn't exist, we may have deleted the row already,
		// no need to add index again.
		return false, nil
	} else if err != nil {
		return false, errors.Trace(err)
	}

	return true, nil
}

// backfillColumnInTxn deals with a part of backfilling column data in a Transaction.
// This part of the column data rows is defaultSmallBatchCnt.
func (d *ddl) backfillColumnInTxn(t table.Table, colID int64, handles []int64, colMap map[int64]*types.FieldType,
	defaultVal types.Datum, txn kv.Transaction) (int64, error) {
	nextHandle := handles[0]
	for _, handle := range handles {
		log.Debug("[ddl] backfill column...", handle)
		rowKey := t.RecordKey(handle)
		rowVal, err := txn.Get(rowKey)
		if terror.ErrorEqual(err, kv.ErrNotExist) {
			// If row doesn't exist, skip it.
			continue
		}
		if err != nil {
			return 0, errors.Trace(err)
		}

		rowColumns, err := tablecodec.DecodeRow(rowVal, colMap)
		if err != nil {
			return 0, errors.Trace(err)
		}
		if _, ok := rowColumns[colID]; ok {
			// The column is already added by update or insert statement, skip it.
			continue
		}

		newColumnIDs := make([]int64, 0, len(rowColumns)+1)
		newRow := make([]types.Datum, 0, len(rowColumns)+1)
		for colID, val := range rowColumns {
			newColumnIDs = append(newColumnIDs, colID)
			newRow = append(newRow, val)
		}
		newColumnIDs = append(newColumnIDs, colID)
		newRow = append(newRow, defaultVal)
		newRowVal, err := tablecodec.EncodeRow(newRow, newColumnIDs)
		if err != nil {
			return 0, errors.Trace(err)
		}
		err = txn.Set(rowKey, newRowVal)
		if err != nil {
			return 0, errors.Trace(err)
		}
	}

	return nextHandle, nil
}

func fetchRowColVals(txn kv.Transaction, t table.Table, handle int64, indexInfo *model.IndexInfo) ([]types.Datum, error) {
	// fetch datas
	cols := t.Cols()
	vals := make([]types.Datum, 0, len(indexInfo.Columns))
	for _, v := range indexInfo.Columns {
		col := cols[v.Offset]
		k := t.RecordKey(handle, col)
		data, err := txn.Get(k)
		if err != nil {
			return nil, errors.Trace(err)
		}
		val, err := tables.DecodeValue(data, &col.FieldType)
		if err != nil {
			return nil, errors.Trace(err)
		}
		vals = append(vals, val)
	}

	return vals, nil
}

func fetchRowColVals(txn kv.Transaction, t table.Table, handle int64, indexInfo *model.IndexInfo) ([]interface{}, error) {
	// fetch datas
	cols := t.Cols()
	var vals []interface{}
	for _, v := range indexInfo.Columns {
		var val interface{}

		col := cols[v.Offset]
		k := t.RecordKey(handle, col)
		data, err := txn.Get(k)
		if err != nil {
			return nil, errors.Trace(err)
		}
		val, err = t.DecodeValue(data, col)
		if err != nil {
			return nil, errors.Trace(err)
		}
		vals = append(vals, val)
	}

	return vals, nil
}

func fetchRowColVals(txn kv.Transaction, t table.Table, handle int64, indexInfo *model.IndexInfo) ([]types.Datum, error) {
	// fetch datas
	cols := t.Cols()
	vals := make([]types.Datum, 0, len(indexInfo.Columns))
	for _, v := range indexInfo.Columns {
		col := cols[v.Offset]
		k := t.RecordKey(handle, col)
		data, err := txn.Get(k)
		if err != nil {
			if terror.ErrorEqual(err, kv.ErrNotExist) && !mysql.HasNotNullFlag(col.Flag) {
				vals = append(vals, types.Datum{})
				continue
			}
			return nil, errors.Trace(err)
		}
		val, err := tables.DecodeValue(data, &col.FieldType)
		if err != nil {
			return nil, errors.Trace(err)
		}
		vals = append(vals, val)
	}

	return vals, nil
}