Method explainStatement

backend/plugin/db/spanner/spanner.go:566–615

explainStatement returns the query plan for the given statement as JSON.

(ctx context.Context, statement string)

// explainStatement returns the query plan for the given statement as JSON.
func (d *Driver) explainStatement(ctx context.Context, statement string) ([]*v1pb.QueryResult, error) {
	if d.client == nil {
		return nil, errors.New("spanner client is not initialized, database name may be missing")
	}

	stmts, err := util.SanitizeSQL(statement)
	if err != nil {
		return nil, err
	}

	var results []*v1pb.QueryResult
	for _, stmt := range stmts {
		startTime := time.Now()
		queryResult, err := func() (*v1pb.QueryResult, error) {
			plan, err := d.client.Single().AnalyzeQuery(ctx, spanner.NewStatement(stmt))
			if err != nil {
				return nil, err
			}

			// Convert the query plan to JSON
			planJSON, err := convertQueryPlanToJSON(plan)
			if err != nil {
				return nil, errors.Wrap(err, "failed to convert query plan to JSON")
			}

			return &v1pb.QueryResult{
				ColumnNames:     []string{"QUERY PLAN"},
				ColumnTypeNames: []string{"JSON"},
				Rows: []*v1pb.QueryRow{
					{
						Values: []*v1pb.RowValue{
							{Kind: &v1pb.RowValue_StringValue{StringValue: planJSON}},
						},
					},
				},
			}, nil
		}()
		if err != nil {
			queryResult = &v1pb.QueryResult{
				Error: err.Error(),
			}
		}
		queryResult.Statement = stmt
		queryResult.Latency = durationpb.New(time.Since(startTime))
		queryResult.RowsCount = int64(len(queryResult.Rows))
		results = append(results, queryResult)
	}

	return results, nil
}

// PlanNode represents a node in the Spanner query plan for JSON serialization.
type PlanNode struct {