{\
  "steps": [\
    {\
      "join_preparation": {\
        "select_id": 1,\
        "steps": [\
          {\
            "expanded_query": "select count(0) AS `count(*)` from (t1 join t2 on(t1.a = t2.a and t1.b = t2.b and (t1.c = t2.c or t1.c is null and t2.c is null) and t1.d < t2.d))"\
          }\
        ]\
      }\
    },\
    {\
      "join_optimization": {\
        "select_id": 1,\
        "steps": [\
          {\
            "condition_processing": {\
              "condition": "WHERE",\
              "original_condition": "t1.a = t2.a and t1.b = t2.b and (t1.c = t2.c or t1.c is null and t2.c is null) and t1.d < t2.d",\
              "steps": [\
                {\
                  "transformation": "equality_propagation",\
                  "resulting_condition": "(multiple equal(t1.c, t2.c) or t1.c is null and t2.c is null) and t1.d < t2.d and multiple equal(t1.a, t2.a) and multiple equal(t1.b, t2.b)"\
                },\
                {\
                  "transformation": "constant_propagation",\
                  "resulting_condition": "(multiple equal(t1.c, t2.c) or t1.c is null and t2.c is null) and t1.d < t2.d and multiple equal(t1.a, t2.a) and multiple equal(t1.b, t2.b)"\
                },\
                {\
                  "transformation": "trivial_condition_removal",\
                  "resulting_condition": "(multiple equal(t1.c, t2.c) or t1.c is null and t2.c is null) and t1.d < t2.d and multiple equal(t1.a, t2.a) and multiple equal(t1.b, t2.b)"\
                }\
              ]\
            }\
          },\
          {\
            "ref_optimizer_key_uses": [\
              {\
                "table": "t1",\
                "index": "t1_ix1",\
                "field": "a",\
                "equals": "t2.a",\
                "null_rejecting": true\
              },\
              {\
                "table": "t1",\
                "index": "t1_ix1",\
                "field": "b",\
                "equals": "t2.b",\
                "null_rejecting": true\
              },\
              {\
                "table": "t1",\
                "index": "t1_ix1",\
                "field": "c",\
                "equals": "t2.c",\
                "null_rejecting": false\
              },\
              {\
                "table": "t2",\
                "index": "t2_ix1",\
                "field": "a",\
                "equals": "t1.a",\
                "null_rejecting": true\
              },\
              {\
                "table": "t2",\
                "index": "t2_ix1",\
                "field": "b",\
                "equals": "t1.b",\
                "null_rejecting": true\
              }\
            ]\
          },\
          {\
            "rows_estimation": [\
              {\
                "selectivity_for_indexes": [],\
                "selectivity_for_columns": [],\
                "cond_selectivity": 1\
              },\
              {\
                "table": "t1",\
                "table_scan": {\
                  "rows": 1007765,\
                  "read_cost": 134.4112522,\
                  "read_and_compare_cost": 166.6597322\
                }\
              },\
              {\
                "selectivity_for_indexes": [],\
                "selectivity_for_columns": [],\
                "cond_selectivity": 1\
              },\
              {\
                "table": "t2",\
                "table_scan": {\
                  "rows": 997545,\
                  "read_cost": 133.0724322,\
                  "read_and_compare_cost": 164.9938722\
                }\
              }\
            ]\
          },\
          {\
            "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": []\
              }\
            ]\
          },\
          {\
            "considered_execution_plans": [\
              {\
                "plan_prefix": "",\
                "get_costs_for_tables": [\
                  {\
                    "best_access_path": {\
                      "table": "t2",\
                      "plan_details": {\
                        "record_count": 1\
                      },\
                      "considered_access_paths": [\
                        {\
                          "access_type": "scan",\
                          "rows": 997545,\
                          "rows_after_filter": 997545,\
                          "rows_out": 997545,\
                          "cost": 164.9938722,\
                          "index_only": false,\
                          "chosen": true\
                        }\
                      ],\
                      "chosen_access_method": {\
                        "type": "scan",\
                        "rows_read": 997545,\
                        "rows_out": 997545,\
                        "cost": 164.9938722,\
                        "uses_join_buffering": false\
                      }\
                    }\
                  },\
                  {\
                    "best_access_path": {\
                      "table": "t1",\
                      "plan_details": {\
                        "record_count": 1\
                      },\
                      "considered_access_paths": [\
                        {\
                          "access_type": "scan",\
                          "rows": 1007765,\
                          "rows_after_filter": 1007765,\
                          "rows_out": 1007765,\
                          "cost": 166.6597322,\
                          "index_only": false,\
                          "chosen": true\
                        }\
                      ],\
                      "chosen_access_method": {\
                        "type": "scan",\
                        "rows_read": 1007765,\
                        "rows_out": 1007765,\
                        "cost": 166.6597322,\
                        "uses_join_buffering": false\
                      }\
                    }\
                  }\
                ]\
              },\
              {\
                "plan_prefix": "",\
                "table": "t2",\
                "rows_for_plan": 997545,\
                "cost_for_plan": 164.9938722,\
                "rest_of_plan": [\
                  {\
                    "plan_prefix": "t2",\
                    "get_costs_for_tables": [\
                      {\
                        "best_access_path": {\
                          "table": "t1",\
                          "plan_details": {\
                            "record_count": 997545\
                          },\
                          "considered_access_paths": [\
                            {\
                              "access_type": "ref_or_null",\
                              "index": "t1_ix1",\
                              "rows": 2,\
                              "cost": 3599.566643,\
                              "chosen": true\
                            },\
                            {\
                              "access_type": "scan_with_join_cache",\
                              "rows": 1007765,\
                              "rows_after_filter": 1007765,\
                              "rows_out": 2,\
                              "cost": 93368095.52,\
                              "cost_without_join_buffer": 163971445.1,\
                              "index_only": false,\
                              "chosen": false\
                            }\
                          ],\
                          "chosen_access_method": {\
                            "type": "ref_or_null",\
                            "rows_read": 2,\
                            "rows_out": 2,\
                            "cost": 3599.566643,\
                            "uses_join_buffering": false\
                          }\
                        }\
                      }\
                    ]\
                  },\
                  {\
                    "plan_prefix": "t2",\
                    "table": "t1",\
                    "rows_for_plan": 1995090,\
                    "cost_for_plan": 3764.560515\
                  }\
                ]\
              },\
              {\
                "plan_prefix": "",\
                "table": "t1",\
                "rows_for_plan": 1007765,\
                "cost_for_plan": 166.6597322,\
                "rest_of_plan": [\
                  {\
                    "plan_prefix": "t1",\
                    "get_costs_for_tables": [\
                      {\
                        "best_access_path": {\
                          "table": "t2",\
                          "plan_details": {\
                            "record_count": 1007765\
                          },\
                          "considered_access_paths": [\
                            {\
                              "access_type": "ref",\
                              "index": "t2_ix1",\
                              "used_range_estimates": false,\
                              "reason": "not available",\
                              "rows": 1,\
                              "cost": 1837.642432,\
                              "chosen": true\
                            },\
                            {\
                              "access_type": "scan_with_join_cache",\
                              "rows": 997545,\
                              "rows_after_filter": 997545,\
                              "rows_out": 1,\
                              "cost": 93368150.57,\
                              "cost_without_join_buffer": 163972562,\
                              "index_only": false,\
                              "chosen": false\
                            }\
                          ],\
                          "chosen_access_method": {\
                            "type": "ref",\
                            "index": "t2_ix1",\
                            "rows_read": 1,\
                            "rows_out": 1,\
                            "cost": 1837.642432,\
                            "uses_join_buffering": false\
                          }\
                        }\
                      }\
                    ]\
                  },\
                  {\
                    "plan_prefix": "t1",\
                    "table": "t2",\
                    "rows_for_plan": 1007765,\
                    "cost_for_plan": 2004.302164\
                  }\
                ]\
              }\
            ]\
          },\
          {\
            "best_join_order": ["t1", "t2"],\
            "rows": 1007765,\
            "cost": 2004.302164\
          },\
          {\
            "substitute_best_equal": {\
              "condition": "WHERE",\
              "resulting_condition": "t2.a = t1.a and t2.b = t1.b and (t2.c = t1.c or t1.c is null and t2.c is null) and t1.d < t2.d"\
            }\
          },\
          {\
            "attaching_conditions_to_tables": {\
              "attached_conditions_computation": [],\
              "attached_conditions_summary": [\
                {\
                  "table": "t1",\
                  "attached_condition": "t1.a is not null and t1.b is not null"\
                },\
                {\
                  "table": "t2",\
                  "attached_condition": "(t2.c = t1.c or t1.c is null and t2.c is null) and t1.d < t2.d"\
                }\
              ]\
            }\
          },\
          {\
            "make_join_readinfo": []\
          },\
          {\
            "prepare_sum_aggregators": {\
              "function": "count(0)",\
              "aggregator_type": "simple"\
            }\
          }\
        ]\
      }\
    },\
    {\
      "join_execution": {\
        "select_id": 1,\
        "steps": []\
      }\
    }\
  ]\
}