mysql> SELECT * FROM information_schema.OPTIMIZER_TRACE \G
*************************** 1. row ***************************
                            QUERY: select * from test_ddl  where  addr="hangzhou" order by gmt_create  limit 1
                            TRACE: {
  "steps": [
    {
      "join_preparation": {
        "select#": 1,
        "steps": [
          {
            "expanded_query": "/* select#1 */ select `test_ddl`.`id` AS `id`,`test_ddl`.`addr` AS `addr`,`test_ddl`.`name1` AS `name1`,`test_ddl`.`name` AS `name`,`test_ddl`.`gmt_create` AS `gmt_create` from `test_ddl` where (`test_ddl`.`addr` = 'hangzhou') order by `test_ddl`.`gmt_create` limit 1"
          }
        ]
      }
    },
    {
      "join_optimization": {
        "select#": 1,
        "steps": [
          {
            "condition_processing": {
              "condition": "WHERE",
              "original_condition": "(`test_ddl`.`addr` = 'hangzhou')",
              "steps": [
                {
                  "transformation": "equality_propagation",
                  "resulting_condition": "multiple equal('hangzhou', `test_ddl`.`addr`)"
                },
                {
                  "transformation": "constant_propagation",
                  "resulting_condition": "multiple equal('hangzhou', `test_ddl`.`addr`)"
                },
                {
                  "transformation": "trivial_condition_removal",
                  "resulting_condition": "multiple equal('hangzhou', `test_ddl`.`addr`)"
                }
              ]
            }
          },
          {
            "substitute_generated_columns": {
            }
          },
          {
            "table_dependencies": [
              {
                "table": "`test_ddl`",
                "row_may_be_null": false,
                "map_bit": 0,
                "depends_on_map_bits": [
                ]
              }
            ]
          },
          {
            "ref_optimizer_key_uses": [
              {
                "table": "`test_ddl`",
                "field": "addr",
                "equals": "'hangzhou'",
                "null_rejecting": true
              }
            ]
          },
          {
            "rows_estimation": [
              {
                "table": "`test_ddl`",
                "range_analysis": {
                  "table_scan": {
                    "rows": 39,
                    "cost": 6.25
                  },
                  "potential_range_indexes": [
                    {
                      "index": "PRIMARY",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "idx_addr_name_name1",
                      "usable": true,
                      "key_parts": [
                        "addr",
                        "id"
                      ]
                    },
                    {
                      "index": "idx_name1",
                      "usable": false,
                      "cause": "not_applicable"
                    },
                    {
                      "index": "idx_gmt_create",
                      "usable": false,
                      "cause": "not_applicable"
                    }
                  ],
                  "setup_range_conditions": [
                  ],
                  "group_index_range": {
                    "chosen": false,
                    "cause": "not_group_by_or_distinct"
                  },
                  "skip_scan_range": {
                    "potential_skip_scan_indexes": [
                      {
                        "index": "idx_addr_name_name1",
                        "usable": false,
                        "cause": "query_references_nonkey_column"
                      }
                    ]
                  },
                  "analyzing_range_alternatives": {
                    "range_scan_alternatives": [
                      {
                        "index": "idx_addr_name_name1",
                        "ranges": [
                          "addr = 'hangzhou'"
                        ],
                        "index_dives_for_eq_ranges": true,
                        "rowid_ordered": true,
                        "using_mrr": false,
                        "index_only": false,
                        "in_memory": 1,
                        "rows": 14,
                        "cost": 5.16,
                        "chosen": true
                      }
                    ],
                    "analyzing_roworder_intersect": {
                      "usable": false,
                      "cause": "too_few_roworder_scans"
                    }
                  },
                  "chosen_range_access_summary": {
                    "range_access_plan": {
                      "type": "range_scan",
                      "index": "idx_addr_name_name1",
                      "rows": 14,
                      "ranges": [
                        "addr = 'hangzhou'"
                      ]
                    },
                    "rows_for_plan": 14,
                    "cost_for_plan": 5.16,
                    "chosen": true
                  }
                }
              }
            ]
          },
          {
            "considered_execution_plans": [
              {
                "plan_prefix": [
                ],
                "table": "`test_ddl`",
                "best_access_path": {
                  "considered_access_paths": [
                    {
                      "access_type": "ref",
                      "index": "idx_addr_name_name1",
                      "rows": 14,
                      "cost": 2.15,
                      "chosen": true
                    },
                    {
                      "access_type": "range",
                      "range_details": {
                        "used_index": "idx_addr_name_name1"
                      },
                      "chosen": false,
                      "cause": "heuristic_index_cheaper"
                    }
                  ]
                },
                "condition_filtering_pct": 100,
                "rows_for_plan": 14,
                "cost_for_plan": 2.15,
                "chosen": true
              }
            ]
          },
          {
            "attaching_conditions_to_tables": {
              "original_condition": "(`test_ddl`.`addr` = 'hangzhou')",
              "attached_conditions_computation": [
              ],
              "attached_conditions_summary": [
                {
                  "table": "`test_ddl`",
                  "attached": "(`test_ddl`.`addr` = 'hangzhou')"
                }
              ]
            }
          },
          {
            "optimizing_distinct_group_by_order_by": {
              "simplifying_order_by": {
                "original_clause": "`test_ddl`.`gmt_create`",
                "items": [
                  {
                    "item": "`test_ddl`.`gmt_create`"
                  }
                ],
                "resulting_clause_is_simple": true,
                "resulting_clause": "`test_ddl`.`gmt_create`"
              }
            }
          },
          {
            "reconsidering_access_paths_for_index_ordering": {
              "clause": "ORDER BY",
              "steps": [
              ],
              "index_order_summary": {
                "table": "`test_ddl`",
                "index_provides_order": true,
                "order_direction": "asc",
                "index": "idx_gmt_create",
                "plan_changed": true,
                "access_type": "index"
              }
            }
          },
          {
            "finalizing_table_conditions": [
              {
                "table": "`test_ddl`",
                "original_table_condition": "(`test_ddl`.`addr` = 'hangzhou')",
                "final_table_condition   ": "(`test_ddl`.`addr` = 'hangzhou')"
              }
            ]
          },
          {
            "refine_plan": [
              {
                "table": "`test_ddl`"
              }
            ]
          },
          {
            "considering_tmp_tables": [
            ]
          }
        ]
      }
    },
    {
      "join_execution": {
        "select#": 1,
        "steps": [
        ]
      }
    }
  ]
}
MISSING_BYTES_BEYOND_MAX_MEM_SIZE: 0
          INSUFFICIENT_PRIVILEGES: 0
1 row in set (0.01 sec)