経緯

Spannerのコンソールを開けば見れるが、めんどう

リポジトリ

https://github.com/nozo-moto/Ratchet

使い方

$ spanner_queryplan --project $PROJECT k --instance $INSTANCE --database $DATABASE --credentials_file $YOUR_CREDENTIALS_FILE queryplan "SELECT * FROM hoge"
Run QueryPlan
Query:  SELECT * FROM hoge
----------
 Distributed Union
 Local Distributed Union
  Serialize Result:
   TableScan:hoge UserId:=UserId Created:=Created UUID:=UUID Data:=Data

コード

メインの部分
Spannerに対してリクエストを送ると、gRPCで返ってくるので頑張ってデータ抜き取って出力する
多分もっといいやり方がある。

// GetQueryPlan execute query plan
func (c *Client) GetQueryPlan(ctx context.Context, query string) (string, error) {
    // Create Session
    databaseName := fmt.Sprintf("projects/%s/instances/%s/databases/%s",
        c.config.Project, c.config.Instance, c.config.Database,
    )
    createSessionReq := &spannerpb.CreateSessionRequest{
        Database: databaseName,
    }
    session, err := c.spannerNomalClient.CreateSession(ctx, createSessionReq)
    if err != nil {
        return "", err
    }
    // Run Execute Sql Requeset
    req := &spannerpb.ExecuteSqlRequest{
        Session:   session.Name,
        Sql:       query,
        QueryMode: spannerpb.ExecuteSqlRequest_PLAN,
    }
    stream, err := c.spannerNomalClient.ExecuteStreamingSql(ctx, req)
    if err != nil {
        return "", err
    }
    var res string
    // Read response
    for {
        resp, err := stream.Recv()
        if err == io.EOF {
            break
        }
        if err != nil {
            return "", err
        }
        // Get response node
        nodes := resp.GetStats().GetQueryPlan().PlanNodes
        // search node by index from Response Nodes
        searchPlanNode := func(index int32) *spannerpb.PlanNode {
            for _, node := range nodes {
                if node.Index == index {
                    return node
                }
            }
            return nil
        }
        // make out put text by dfs
        indentlevel := 0
        var createOutput func(nodeId int32) string
        createOutput = func(nodeId int32) string {
            var result string
            node := searchPlanNode(nodeId)
            // 出力文を作成
            if node.DisplayName != "Reference" && node.DisplayName != "Function" && node.DisplayName != "Constant" && node.DisplayName != "Array Constructor" {
                result = strings.Repeat(" ", indentlevel)
                // Get Display Name
                if node.DisplayName == "Scan" {
                    field := node.Metadata.Fields
                    result += field["scan_type"].GetStringValue() + ":" + field["scan_target"].GetStringValue() + " "
                } else if node.DisplayName == "Distributed Union" {
                    result += node.Metadata.Fields["call_type"].GetStringValue() + " " + node.DisplayName
                } else {
                    result += node.DisplayName + ": "
                }
                // Get Content
                for _, nodeChild := range node.ChildLinks {
                    searchednode := searchPlanNode(nodeChild.ChildIndex)
                    if searchednode.DisplayName == "Reference" && node.DisplayName != "Serialize Result" {
                        // Printout valiable matching
                        result += nodeChild.Variable + ":=" + searchednode.ShortRepresentation.Description + " "
                    } else if nodeChild.Type != "Split Range" {
                        result += nodeChild.Type + " "
                    }
                }
                result += "\n"
            }
            // recursion
            for _, nodeChild := range node.ChildLinks {
                indentlevel++
                result += createOutput(nodeChild.ChildIndex)
                indentlevel--
            }
            return result
        }
        res = createOutput(nodes[0].Index)
    }
    return res, nil
}

以上