{
  "steps": [
    {
      "join_preparation": {
        "select#": 1,
        "steps": [
          {
            "IN_uses_bisection": true
          },
          {
            "expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t1`.`b` AS `b`,`t2`.`a` AS `a`,`t2`.`b` AS `b` from `t1` join `t2` where ((`t1`.`a` < 50) and (`t1`.`b` = `t2`.`b`) and (`t2`.`a` in (1,2,3)))"
          }
        ]
      }
    },
    {
      "join_optimization": {
        "select#": 1,
        "steps": [
          {
            "condition_processing": {
              "condition": "WHERE",
              "original_condition": "((`t1`.`a` < 50) and (`t1`.`b` = `t2`.`b`) and (`t2`.`a` in (1,2,3)))",
              "steps": [
                {
                  "transformation": "equality_propagation",
                  "resulting_condition": "((`t1`.`a` < 50) and (`t2`.`a` in (1,2,3)) and multiple equal(`t1`.`b`, `t2`.`b`))"
                },
                {
                  "transformation": "constant_propagation",
                  "resulting_condition": "((`t1`.`a` < 50) and (`t2`.`a` in (1,2,3)) and multiple equal(`t1`.`b`, `t2`.`b`))"
                },
                {
                  "transformation": "trivial_condition_removal",
                  "resulting_condition": "((`t1`.`a` < 50) and (`t2`.`a` in (1,2,3)) and multiple equal(`t1`.`b`, `t2`.`b`))"
                }
              ]
            }
          },
          {
            "substitute_generated_columns": {
            }
          },
          {
            "table_dependencies": [
              {
                "table": "`t1`",
                "row_may_be_null": false,
                "map_bit": 0,
                "depends_on_map_bits": [
                ]
              },
              {
                "table": "`t2`",
                "row_may_be_null": false,
                "map_bit": 1,
                "depends_on_map_bits": [
                ]
              }
            ]
          },
          {
            "ref_optimizer_key_uses": [
            ]
          },
          {
            "rows_estimation": [
              {
                "table": "`t1`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 1000,
                    "cost": 103.1
                  },
                  "potential_range_indexes": [
                    {
                      "index": "a",
                      "usable": true,
                      "key_parts": [
                        "a"
                      ]
                    }
                  ],
                  "setup_range_conditions": [
                  ],
                  "group_index_range": {
                    "chosen": false,
                    "cause": "not_single_table"
                  },
                  "analyzing_range_alternatives": {
                    "range_scan_alternatives": [
                      {
                        "index": "a",
                        "ranges": [
                          "NULL < a < 50"
                        ],
                        "index_dives_for_eq_ranges": true,
                        "rowid_ordered": false,
                        "using_mrr": false,
                        "index_only": false,
                        "rows": 50,
                        "cost": 17.76,
                        "chosen": true
                      }
                    ],
                    "analyzing_roworder_intersect": {
                      "usable": false,
                      "cause": "too_few_roworder_scans"
                    }
                  },
                  "chosen_range_access_summary": {
                    "range_access_plan": {
                      "type": "range_scan",
                      "index": "a",
                      "rows": 50,
                      "ranges": [
                        "NULL < a < 50"
                      ]
                    },
                    "rows_for_plan": 50,
                    "cost_for_plan": 17.76,
                    "chosen": true
                  }
                }
              },
              {
                "table": "`t2`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 1000,
                    "cost": 103.1
                  },
                  "potential_range_indexes": [
                    {
                      "index": "a",
                      "usable": true,
                      "key_parts": [
                        "a"
                      ]
                    }
                  ],
                  "setup_range_conditions": [
                  ],
                  "group_index_range": {
                    "chosen": false,
                    "cause": "not_single_table"
                  },
                  "analyzing_range_alternatives": {
                    "range_scan_alternatives": [
                      {
                        "index": "a",
                        "ranges": [
                          "1 <= a <= 1",
                          "2 <= a <= 2",
                          "3 <= a <= 3"
                        ],
                        "index_dives_for_eq_ranges": true,
                        "rowid_ordered": false,
                        "using_mrr": false,
                        "index_only": false,
                        "rows": 3,
                        "cost": 1.81,
                        "chosen": true
                      }
                    ],
                    "analyzing_roworder_intersect": {
                      "usable": false,
                      "cause": "too_few_roworder_scans"
                    }
                  },
                  "chosen_range_access_summary": {
                    "range_access_plan": {
                      "type": "range_scan",
                      "index": "a",
                      "rows": 3,
                      "ranges": [
                        "1 <= a <= 1",
                        "2 <= a <= 2",
                        "3 <= a <= 3"
                      ]
                    },
                    "rows_for_plan": 3,
                    "cost_for_plan": 1.81,
                    "chosen": true
                  }
                }
              }
            ]
          },
          {
            "considered_execution_plans": [
              {
                "plan_prefix": [
                ],
                "table": "`t2`",
                "best_access_path": {
                  "considered_access_paths": [
                    {
                      "rows_to_scan": 3,
                      "filtering_effect": [
                      ],
                      "final_filtering_effect": 1,
                      "access_type": "range",
                      "range_details": {
                        "used_index": "a"
                      },
                      "resulting_rows": 3,
                      "cost": 2.11,
                      "chosen": true
                    }
                  ]
                },
                "condition_filtering_pct": 100,
                "rows_for_plan": 3,
                "cost_for_plan": 2.11,
                "rest_of_plan": [
                  {
                    "plan_prefix": [
                      "`t2`"
                    ],
                    "table": "`t1`",
                    "best_access_path": {
                      "considered_access_paths": [
                        {
                          "rows_to_scan": 50,
                          "filtering_effect": [
                          ],
                          "final_filtering_effect": 1,
                          "access_type": "range",
                          "range_details": {
                            "used_index": "a"
                          },
                          "resulting_rows": 50,
                          "cost": 68.28,
                          "chosen": true
                        }
                      ]
                    },
                    "condition_filtering_pct": 10,
                    "rows_for_plan": 15,
                    "cost_for_plan": 70.39,
                    "chosen": true
                  }
                ]
              },
              {
                "plan_prefix": [
                ],
                "table": "`t1`",
                "best_access_path": {
                  "considered_access_paths": [
                    {
                      "rows_to_scan": 50,
                      "filtering_effect": [
                      ],
                      "final_filtering_effect": 1,
                      "access_type": "range",
                      "range_details": {
                        "used_index": "a"
                      },
                      "resulting_rows": 50,
                      "cost": 22.76,
                      "chosen": true
                    }
                  ]
                },
                "condition_filtering_pct": 100,
                "rows_for_plan": 50,
                "cost_for_plan": 22.76,
                "pruned_by_heuristic": true
              }
            ]
          },
          {
            "attaching_conditions_to_tables": {
              "original_condition": "((`t1`.`b` = `t2`.`b`) and (`t1`.`a` < 50) and (`t2`.`a` in (1,2,3)))",
              "attached_conditions_computation": [
              ],
              "attached_conditions_summary": [
                {
                  "table": "`t2`",
                  "attached": "(`t2`.`a` in (1,2,3))"
                },
                {
                  "table": "`t1`",
                  "attached": "((`t1`.`b` = `t2`.`b`) and (`t1`.`a` < 50))"
                }
              ]
            }
          },
          {
            "refine_plan": [
              {
                "table": "`t2`",
                "pushed_index_condition": "(`t2`.`a` in (1,2,3))",
                "table_condition_attached": null
              },
              {
                "table": "`t1`",
                "unknown_key_1": {
                  "constant_condition_in_bnl": "(`t1`.`a` < 50)"
                },
                "pushed_index_condition": "(`t1`.`a` < 50)",
                "table_condition_attached": "(`t1`.`b` = `t2`.`b`)"
              }
            ]
          }
        ]
      }
    },
    {
      "join_explain": {
        "select#": 1,
        "steps": [
        ]
      }
    }
  ]
}