Exception in output of multiple execution group statistics

[kevinbin]

stage:
  name: read-only
  runtime: 10s
  workload:
    - clients: 1
      group: a1
    - clients: 2
      group: a2
  trx:
    - file: trx/read-only.sql
      data:
        id:
          generator: "int"
          params:
            max: $params.rows
            dist: normal
        id_100:
          generator: "int-range"
          params:
            range: 100
            max: $params.rows

finch --dsn 'msandbox:msandbox@tcp(127.0.0.1:8032)/finch' ~/workbench/finch/benchmarks/sysbench/read-only.yaml
2024/04/16 09:48:47.511579 stage.go:63: Connected to msandbox:...@tcp(127.0.0.1:8032)/finch
2024/04/16 09:48:47.513378 stage.go:134: [read-only] Running for 10s
2024/04/16 09:48:47.513560 stage.go:154: [read-only] Execution group 1, client group 1, runnning 1 clients, runtime 0s
 interval| duration| runtime| clients|    QPS| min| P999|   max|  r_QPS| r_min| r_P999| r_max| w_QPS| w_min| w_P999| w_max|   TPS| c_min| c_P999| c_max| errors|compute
        1|      5.0|     5.0|       3| 16,190|   0|  229| 7,752| 14,166|     0|    229| 7,752|     0|     0|      0|     0| 1,011|     0|    109|   760|      0|local

 interval| duration| runtime| clients|    QPS| min| P999|   max|  r_QPS| r_min| r_P999| r_max| w_QPS| w_min| w_P999| w_max|   TPS| c_min| c_P999| c_max| errors|compute
        2|      5.0|    10.0|       3| 16,350|   0|  218| 2,721| 14,306|     0|    218| 2,721|     0|     0|      0|     0| 1,021|     0|    125|   405|      0|local

2024/04/16 09:48:57.514471 stage.go:154: [read-only] Execution group 2, client group 1, runnning 2 clients, runtime 0s