mysql optimizer: v2_things

{
  "steps": [
    {
      "join_preparation": {
        "select#": 1,
        "steps": [
          {
            "expanded_query": "/* select#1 */ select `v2_thing`.`id` AS `ID` from `v2_thing` where ((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))"
          }
        ]
      }
    },
    {
      "join_optimization": {
        "select#": 1,
        "steps": [
          {
            "condition_processing": {
              "condition": "WHERE",
              "original_condition": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))",
              "steps": [
                {
                  "transformation": "equality_propagation",
                  "resulting_condition": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))"
                },
                {
                  "transformation": "constant_propagation",
                  "resulting_condition": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))"
                },
                {
                  "transformation": "trivial_condition_removal",
                  "resulting_condition": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))"
                }
              ]
            }
          },
          {
            "substitute_generated_columns": {
            }
          },
          {
            "table_dependencies": [
              {
                "table": "`v2_thing`",
                "row_may_be_null": false,
                "map_bit": 0,
                "depends_on_map_bits": [
                ]
              }
            ]
          },
          {
            "ref_optimizer_key_uses": [
              {
                "table": "`v2_thing`",
                "field": "status",
                "equals": "'C'",
                "null_rejecting": false
              }
            ]
          },
          {
            "rows_estimation": [
              {
                "table": "`v2_thing`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 79054472,
                    "cost": 1.69e7
                  },
                  "potential_range_indexes": [
                    {
                      "index": "PRIMARY",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "idx_status_thing",
                      "usable": true,
                      "key_parts": [
                        "status",
                        "id"
                      ]
                    },
                    {
                      "index": "idx_created_datetime_thing",
                      "usable": true,
                      "key_parts": [
                        "created_datetime",
                        "id"
                      ]
                    },
                    {
                      "index": "idx_clientid_thing",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "idx_external_reference_thing",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "idx_person_contact_type_thing",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "fk_buyer_thing",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "v2_thing_owner_user_id_index",
                      "usable": false,
                      "cause": "not_applicable"
                    }
                  ],
                  "setup_range_conditions": [
                  ],
                  "group_index_range": {
                    "chosen": false,
                    "cause": "not_group_by_or_distinct"
                  },
                  "analyzing_range_alternatives": {
                    "range_scan_alternatives": [
                      {
                        "index": "idx_status_thing",
                        "ranges": [
                          "C <= status <= C"
                        ],
                        "index_dives_for_eq_ranges": true,
                        "rowid_ordered": true,
                        "using_mrr": false,
                        "index_only": false,
                        "rows": 39527236,
                        "cost": 4.74e7,
                        "chosen": false,
                        "cause": "cost"
                      },
                      {
                        "index": "idx_created_datetime_thing",
                        "ranges": [
                          "0x999ef970bb < created_datetime"
                        ],
                        "index_dives_for_eq_ranges": true,
                        "rowid_ordered": false,
                        "using_mrr": false,
                        "index_only": false,
                        "rows": 10072076,
                        "cost": 1.21e7,
                        "chosen": true
                      }
                    ],
                    "analyzing_roworder_intersect": {
                      "usable": false,
                      "cause": "too_few_roworder_scans"
                    }
                  },
                  "chosen_range_access_summary": {
                    "range_access_plan": {
                      "type": "range_scan",
                      "index": "idx_created_datetime_thing",
                      "rows": 10072076,
                      "ranges": [
                        "0x999ef970bb < created_datetime"
                      ]
                    },
                    "rows_for_plan": 10072076,
                    "cost_for_plan": 1.21e7,
                    "chosen": true
                  }
                }
              }
            ]
          },
          {
            "considered_execution_plans": [
              {
                "plan_prefix": [
                ],
                "table": "`v2_thing`",
                "best_access_path": {
                  "considered_access_paths": [
                    {
                      "access_type": "ref",
                      "index": "idx_status_thing",
                      "rows": 3.95e7,
                      "cost": 1.11e7,
                      "chosen": true
                    },
                    {
                      "rows_to_scan": 10072076,
                      "access_type": "range",
                      "range_details": {
                        "used_index": "idx_created_datetime_thing"
                      },
                      "resulting_rows": 503604,
                      "cost": 1.41e7,
                      "chosen": false
                    }
                  ]
                },
                "condition_filtering_pct": 1.2741,
                "rows_for_plan": 503604,
                "cost_for_plan": 1.11e7,
                "chosen": true
              }
            ]
          },
          {
            "attaching_conditions_to_tables": {
              "original_condition": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)) and (`v2_thing`.`status` = 'C'))",
              "attached_conditions_computation": [
              ],
              "attached_conditions_summary": [
                {
                  "table": "`v2_thing`",
                  "attached": "((`v2_thing`.`demo` = 'N') and (`v2_thing`.`created_datetime` > (now() - interval 50 day)))"
                }
              ]
            }
          },
          {
            "refine_plan": [
              {
                "table": "`v2_thing`"
              }
            ]
          }
        ]
      }
    },
    {
      "join_explain": {
        "select#": 1,
        "steps": [
        ]
      }
    }
  ]
}