{
    "steps": [
	{
	    "join_preparation": {
		"select#": 2,
		"steps": [
		    {
			"expanded_query": "/* select#2 */ select `m`.`id` AS `id` from `messaggio` `m` where ((`m`.`idarticolo` = 'repnews_271330') and (`m`.`idpadre` = 0) and (`m`.`pubblica` = 1)) order by `m`.`data` desc limit 50"
		    }
		]
	    }
	},
	{
	    "join_preparation": {
		"select#": 1,
		"steps": [
		    {
			"expanded_query": "/* select#1 */ select `messaggio`.`id` AS `id`,`messaggio`.`data` AS `data`,`allegati`.`id` AS `id` from (((/* select#2 */ select `m`.`id` AS `id` from `messaggio` `m` where ((`m`.`idarticolo` = 'repnews_271330') and (`m`.`idpadre` = 0) and (`m`.`pubblica` = 1)) order by `m`.`data` desc limit 50) `m_padre` join `messaggio` on(((`m_padre`.`id` = `messaggio`.`idpadre`) or (`m_padre`.`id` = `messaggio`.`id`)))) left join `allegati` on((`messaggio`.`id` = `allegati`.`idpost`))) order by `messaggio`.`data` desc,`messaggio`.`id` desc,`allegati`.`id`"
		    }
		]
	    }
	},
	{
	    "join_optimization": {
		"select#": 1,
		"steps": [
		    {
			"join_optimization": {
			    "select#": 2,
			    "steps": [
				{
				    "condition_processing": {
					"condition": "WHERE",
					"original_condition": "((`m`.`idarticolo` = 'repnews_271330') and (`m`.`idpadre` = 0) and (`m`.`pubblica` = 1))",
					"steps": [
					    {
						"transformation": "equality_propagation",
						"resulting_condition": "(multiple equal('repnews_271330', `m`.`idarticolo`) and multiple equal(0, `m`.`idpadre`) and multiple equal(1, `m`.`pubblica`))"
					    },
					    {
						"transformation": "constant_propagation",
						"resulting_condition": "(multiple equal('repnews_271330', `m`.`idarticolo`) and multiple equal(0, `m`.`idpadre`) and multiple equal(1, `m`.`pubblica`))"
					    },
					    {
						"transformation": "trivial_condition_removal",
						"resulting_condition": "(multiple equal('repnews_271330', `m`.`idarticolo`) and multiple equal(0, `m`.`idpadre`) and multiple equal(1, `m`.`pubblica`))"
					    }
					]
				    }
				},
				{
				    "table_dependencies": [
					{
					    "table": "`messaggio` `m`",
					    "row_may_be_null": false,
					    "map_bit": 0,
					    "depends_on_map_bits": [
					    ]
					}
				    ]
				},
				{
				    "ref_optimizer_key_uses": [
					{
					    "table": "`messaggio` `m`",
					    "field": "idpadre",
					    "equals": "0",
					    "null_rejecting": false
					},
					{
					    "table": "`messaggio` `m`",
					    "field": "idpadre",
					    "equals": "0",
					    "null_rejecting": false
					},
					{
					    "table": "`messaggio` `m`",
					    "field": "pubblica",
					    "equals": "1",
					    "null_rejecting": false
					},
					{
					    "table": "`messaggio` `m`",
					    "field": "idarticolo",
					    "equals": "'repnews_271330'",
					    "null_rejecting": false
					}
				    ]
				},
				{
				    "rows_estimation": [
					{
					    "table": "`messaggio` `m`",
					    "range_analysis": {
						"table_scan": {
						    "rows": 2445095,
						    "cost": 567805
						},
						"potential_range_indices": [
						    {
							"index": "PRIMARY",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idevento_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idpadre",
							"usable": true,
							"key_parts": [
							    "idpadre",
							    "id"
							]
						    },
						    {
							"index": "ideventoidpadre_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "ideventoidpadrepubblica_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idpadrepubblica_idx",
							"usable": true,
							"key_parts": [
							    "idpadre",
							    "pubblica",
							    "id"
							]
						    },
						    {
							"index": "ididpadrepubblica",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idUtente_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "data_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "nome",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idbrand_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "idarticolo_idx",
							"usable": true,
							"key_parts": [
							    "idarticolo",
							    "id"
							]
						    },
						    {
							"index": "commento_ft_idx",
							"usable": false,
							"cause": "not_applicable"
						    },
						    {
							"index": "titolo_ft_idx",
							"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": "idpadre",
							    "ranges": [
								"0 <= idpadre <= 0"
							    ],
							    "index_dives_for_eq_ranges": true,
							    "rowid_ordered": true,
							    "using_mrr": false,
							    "index_only": false,
							    "rows": 1222547,
							    "cost": 1.47e6,
							    "chosen": false,
							    "cause": "cost"
							},
							{
							    "index": "idpadrepubblica_idx",
							    "ranges": [
								"0 <= idpadre <= 0 AND 1 <= pubblica <= 1"
							    ],
							    "index_dives_for_eq_ranges": true,
							    "rowid_ordered": true,
							    "using_mrr": false,
							    "index_only": false,
							    "rows": 1222547,
							    "cost": 1.47e6,
							    "chosen": false,
							    "cause": "cost"
							},
							{
							    "index": "idarticolo_idx",
							    "ranges": [
								"repnews_271330 <= idarticolo <= repnews_271330"
							    ],
							    "index_dives_for_eq_ranges": true,
							    "rowid_ordered": true,
							    "using_mrr": false,
							    "index_only": false,
							    "rows": 26,
							    "cost": 32.21,
							    "chosen": true
							}
						    ],
						    "analyzing_roworder_intersect": {
							"intersecting_indices": [
							    {
								"index": "idpadrepubblica_idx",
								"index_scan_cost": 1791,
								"cumulated_index_scan_cost": 1791,
								"disk_sweep_cost": 278008,
								"cumulated_total_cost": 279799,
								"usable": true,
								"matching_rows_now": 1.22e6,
								"isect_covering_with_this_index": false,
								"chosen": true
							    },
							    {
								"index": "idarticolo_idx",
								"index_scan_cost": 1.4032,
								"cumulated_index_scan_cost": 1792.4,
								"disk_sweep_cost": 257,
								"cumulated_total_cost": 2049.4,
								"usable": true,
								"matching_rows_now": 13,
								"isect_covering_with_this_index": false,
								"chosen": true
							    },
							    {
								"index": "idpadre",
								"cumulated_total_cost": 2049.4,
								"usable": false,
								"cause": "does_not_reduce_cost_of_intersect"
							    }
							],
							"clustered_pk": {
							    "clustered_pk_added_to_intersect": false,
							    "cause": "no_clustered_pk_index"
							},
							"chosen": false,
							"cause": "cost"
						    }
						},
						"chosen_range_access_summary": {
						    "range_access_plan": {
							"type": "range_scan",
							"index": "idarticolo_idx",
							"rows": 26,
							"ranges": [
							    "repnews_271330 <= idarticolo <= repnews_271330"
							]
						    },
						    "rows_for_plan": 26,
						    "cost_for_plan": 32.21,
						    "chosen": true
						}
					    }
					}
				    ]
				},
				{
				    "considered_execution_plans": [
					{
					    "plan_prefix": [
					    ],
					    "table": "`messaggio` `m`",
					    "best_access_path": {
						"considered_access_paths": [
						    {
							"access_type": "ref",
							"index": "idpadre",
							"rows": 1.22e6,
							"cost": 480861,
							"chosen": true
						    },
						    {
							"access_type": "ref",
							"index": "idpadrepubblica_idx",
							"rows": 1.22e6,
							"cost": 480861,
							"chosen": false
						    },
						    {
							"access_type": "ref",
							"index": "idarticolo_idx",
							"rows": 26,
							"cost": 31.2,
							"chosen": true
						    },
						    {
							"access_type": "range",
							"cause": "heuristic_index_cheaper",
							"chosen": false
						    }
						]
					    },
					    "cost_for_plan": 31.2,
					    "rows_for_plan": 26,
					    "chosen": true
					}
				    ]
				},
				{
				    "attaching_conditions_to_tables": {
					"original_condition": "((`m`.`pubblica` = 1) and (`m`.`idpadre` = 0) and (`m`.`idarticolo` = 'repnews_271330'))",
					"attached_conditions_computation": [
					],
					"attached_conditions_summary": [
					    {
						"table": "`messaggio` `m`",
						"attached": "((`m`.`pubblica` = 1) and (`m`.`idpadre` = 0) and (`m`.`idarticolo` = 'repnews_271330'))"
					    }
					]
				    }
				},
				{
				    "clause_processing": {
					"clause": "ORDER BY",
					"original_clause": "`m`.`data` desc",
					"items": [
					    {
						"item": "`m`.`data`"
					    }
					],
					"resulting_clause_is_simple": true,
					"resulting_clause": "`m`.`data` desc"
				    }
				},
				{
				    "refine_plan": [
					{
					    "table": "`messaggio` `m`",
					    "pushed_index_condition": "(`m`.`idarticolo` = 'repnews_271330')",
					    "table_condition_attached": "((`m`.`pubblica` = 1) and (`m`.`idpadre` = 0))"
					}
				    ]
				},
				{
				    "added_back_ref_condition": "((`m`.`idarticolo` <=> 'repnews_271330') and ((`m`.`pubblica` = 1) and (`m`.`idpadre` = 0)))"
				},
				{
				    "reconsidering_access_paths_for_index_ordering": {
					"clause": "ORDER BY",
					"index_order_summary": {
					    "table": "`messaggio` `m`",
					    "index_provides_order": false,
					    "order_direction": "undefined",
					    "index": "idarticolo_idx",
					    "plan_changed": false
					}
				    }
				}
			    ]
			}
		    },
		    {
			"transformations_to_nested_joins": {
			    "transformations": [
				"JOIN_condition_to_WHERE",
				"parenthesis_removal"
			    ],
			    "expanded_query": "/* select#1 */ select `messaggio`.`id` AS `id`,`messaggio`.`data` AS `data`,`allegati`.`id` AS `id` from (/* select#2 */ select `m`.`id` AS `id` from `messaggio` `m` where ((`m`.`pubblica` = 1) and (`m`.`idpadre` = 0) and (`m`.`idarticolo` = 'repnews_271330')) order by `m`.`data` desc limit 50) `m_padre` join `messaggio` left join `allegati` on((`messaggio`.`id` = `allegati`.`idpost`)) where ((`m_padre`.`id` = `messaggio`.`idpadre`) or (`m_padre`.`id` = `messaggio`.`id`)) order by `messaggio`.`data` desc,`messaggio`.`id` desc,`allegati`.`id`"
			}
		    },
		    {
			"condition_processing": {
			    "condition": "WHERE",
			    "original_condition": "((`m_padre`.`id` = `messaggio`.`idpadre`) or (`m_padre`.`id` = `messaggio`.`id`))",
			    "steps": [
				{
				    "transformation": "equality_propagation",
				    "resulting_condition": "(multiple equal(`m_padre`.`id`, `messaggio`.`idpadre`) or multiple equal(`m_padre`.`id`, `messaggio`.`id`))"
				},
				{
				    "transformation": "constant_propagation",
				    "resulting_condition": "(multiple equal(`m_padre`.`id`, `messaggio`.`idpadre`) or multiple equal(`m_padre`.`id`, `messaggio`.`id`))"
				},
				{
				    "transformation": "trivial_condition_removal",
				    "resulting_condition": "(multiple equal(`m_padre`.`id`, `messaggio`.`idpadre`) or multiple equal(`m_padre`.`id`, `messaggio`.`id`))"
				}
			    ]
			}
		    },
		    {
			"table_dependencies": [
			    {
				"table": " `m_padre`",
				"row_may_be_null": false,
				"map_bit": 0,
				"depends_on_map_bits": [
				]
			    },
			    {
				"table": "`messaggio`",
				"row_may_be_null": false,
				"map_bit": 1,
				"depends_on_map_bits": [
				]
			    },
			    {
				"table": "`allegati`",
				"row_may_be_null": true,
				"map_bit": 2,
				"depends_on_map_bits": [
				    1
				]
			    }
			]
		    },
		    {
			"ref_optimizer_key_uses": [
			    {
				"table": "`allegati`",
				"field": "idpost",
				"equals": "`messaggio`.`id`",
				"null_rejecting": false
			    }
			]
		    },
		    {
			"rows_estimation": [
			    {
				"table": " `m_padre`",
				"table_scan": {
				    "rows": 26,
				    "cost": 11
				}
			    },
			    {
				"table": "`messaggio`",
				"table_scan": {
				    "rows": 2445095,
				    "cost": 78784
				}
			    },
			    {
				"table": "`allegati`",
				"table_scan": {
				    "rows": 400357,
				    "cost": 5479
				}
			    }
			]
		    },
		    {
			"considered_execution_plans": [
			    {
				"plan_prefix": [
				],
				"table": " `m_padre`",
				"best_access_path": {
				    "considered_access_paths": [
					{
					    "access_type": "scan",
					    "rows": 26,
					    "cost": 16.5,
					    "chosen": true
					}
				    ]
				},
				"cost_for_plan": 16.5,
				"rows_for_plan": 26,
				"rest_of_plan": [
				    {
					"plan_prefix": [
					    " `m_padre`"
					],
					"table": "`messaggio`",
					"best_access_path": {
					    "considered_access_paths": [
						{
						    "access_type": "scan",
						    "using_join_cache": true,
						    "rows": 2.45e6,
						    "cost": 1.28e7,
						    "chosen": true
						}
					    ]
					},
					"cost_for_plan": 1.28e7,
					"rows_for_plan": 6.36e7,
					"rest_of_plan": [
					    {
						"plan_prefix": [
						    " `m_padre`",
						    "`messaggio`"
						],
						"table": "`allegati`",
						"best_access_path": {
						    "considered_access_paths": [
							{
							    "access_type": "ref",
							    "index": "idpost_idx",
							    "rows": 1,
							    "cost": 6.36e7,
							    "chosen": true
							},
							{
							    "access_type": "scan",
							    "cause": "covering_index_better_than_full_scan",
							    "chosen": false
							}
						    ]
						},
						"cost_for_plan": 8.91e7,
						"rows_for_plan": 6.36e7,
						"chosen": true
					    }
					]
				    }
				]
			    },
			    {
				"plan_prefix": [
				],
				"table": "`messaggio`",
				"best_access_path": {
				    "considered_access_paths": [
					{
					    "access_type": "scan",
					    "rows": 2.45e6,
					    "cost": 567803,
					    "chosen": true
					}
				    ]
				},
				"cost_for_plan": 567803,
				"rows_for_plan": 2.45e6,
				"rest_of_plan": [
				    {
					"plan_prefix": [
					    "`messaggio`"
					],
					"table": " `m_padre`",
					"best_access_path": {
					    "considered_access_paths": [
						{
						    "access_type": "scan",
						    "using_join_cache": true,
						    "rows": 26,
						    "cost": 1.27e7,
						    "chosen": true
						}
					    ]
					},
					"cost_for_plan": 1.33e7,
					"rows_for_plan": 6.36e7,
					"rest_of_plan": [
					    {
						"plan_prefix": [
						    "`messaggio`",
						    " `m_padre`"
						],
						"table": "`allegati`",
						"best_access_path": {
						    "considered_access_paths": [
							{
							    "access_type": "ref",
							    "index": "idpost_idx",
							    "rows": 1,
							    "cost": 6.36e7,
							    "chosen": true
							},
							{
							    "access_type": "scan",
							    "cause": "covering_index_better_than_full_scan",
							    "chosen": false
							}
						    ]
						},
						"cost_for_plan": 8.96e7,
						"rows_for_plan": 6.36e7,
						"pruned_by_cost": true
					    }
					]
				    },
				    {
					"plan_prefix": [
					    "`messaggio`"
					],
					"table": "`allegati`",
					"best_access_path": {
					    "considered_access_paths": [
						{
						    "access_type": "ref",
						    "index": "idpost_idx",
						    "rows": 1,
						    "cost": 2.45e6,
						    "chosen": true
						},
						{
						    "access_type": "scan",
						    "cause": "covering_index_better_than_full_scan",
						    "chosen": false
						}
					    ]
					},
					"cost_for_plan": 3.5e6,
					"rows_for_plan": 2.45e6,
					"rest_of_plan": [
					    {
						"plan_prefix": [
						    "`messaggio`",
						    "`allegati`"
						],
						"table": " `m_padre`",
						"best_access_path": {
						    "considered_access_paths": [
							{
							    "access_type": "scan",
							    "using_join_cache": true,
							    "rows": 26,
							    "cost": 1.27e7,
							    "chosen": true
							}
						    ]
						},
						"cost_for_plan": 1.62e7,
						"rows_for_plan": 6.36e7,
						"chosen": true
					    }
					]
				    }
				]
			    }
			]
		    },
		    {
			"attaching_conditions_to_tables": {
			    "original_condition": "((`m_padre`.`id` = `messaggio`.`idpadre`) or (`m_padre`.`id` = `messaggio`.`id`))",
			    "attached_conditions_computation": [
			    ],
			    "attached_conditions_summary": [
				{
				    "table": "`messaggio`",
				    "attached": null
				},
				{
				    "table": "`allegati`",
				    "attached": null
				},
				{
				    "table": " `m_padre`",
				    "attached": "((`m_padre`.`id` = `messaggio`.`idpadre`) or (`m_padre`.`id` = `messaggio`.`id`))"
				}
			    ]
			}
		    },
		    {
			"clause_processing": {
			    "clause": "ORDER BY",
			    "original_clause": "`messaggio`.`data` desc,`messaggio`.`id` desc,`allegati`.`id`",
			    "items": [
				{
				    "item": "`messaggio`.`data`"
				},
				{
				    "item": "`messaggio`.`id`"
				},
				{
				    "item": "`allegati`.`id`"
				}
			    ],
			    "resulting_clause_is_simple": false,
			    "resulting_clause": "`messaggio`.`data` desc,`messaggio`.`id` desc,`allegati`.`id`"
			}
		    },
		    {
			"refine_plan": [
			    {
				"table": "`messaggio`",
				"access_type": "table_scan"
			    },
			    {
				"table": "`allegati`"
			    },
			    {
				"table": " `m_padre`",
				"access_type": "table_scan"
			    }
			]
		    }
		]
	    }
	},
	{
	    "join_execution": {
		"select#": 1,
		"steps": [
		    {
			"creating_tmp_table": {
			    "tmp_table_info": {
				"table": " `m_padre`",
				"row_length": 5,
				"key_length": 0,
				"unique_constraint": false,
				"location": "memory (heap)",
				"row_limit_estimate": 3355443
			    }
			}
		    },
		    {
			"join_execution": {
			    "select#": 2,
			    "steps": [
				{
				    "filesort_information": [
					{
					    "direction": "desc",
					    "table": "`messaggio` `m`",
					    "field": "data"
					}
				    ],
				    "filesort_priority_queue_optimization": {
					"limit": 50,
					"rows_estimate": 26963694,
					"row_size": 150,
					"memory_available": 2097152,
					"chosen": true
				    },
				    "filesort_execution": [
				    ],
				    "filesort_summary": {
					"rows": 27,
					"examined_rows": 27,
					"number_of_tmp_files": 0,
					"sort_buffer_size": 8058,
					"sort_mode": "<sort_key, additional_fields>"
				    }
				}
			    ]
			}
		    },
		    {
			"creating_tmp_table": {
			    "tmp_table_info": {
				"table": "intermediate_tmp_table",
				"row_length": 13,
				"key_length": 0,
				"unique_constraint": false,
				"location": "memory (heap)",
				"row_limit_estimate": 1290555
			    }
			}
		    },
		    {
			"filesort_information": [
			    {
				"direction": "desc",
				"table": "intermediate_tmp_table",
				"field": "data"
			    },
			    {
				"direction": "desc",
				"table": "intermediate_tmp_table",
				"field": "id"
			    },
			    {
				"direction": "asc",
				"table": "intermediate_tmp_table",
				"field": "id"
			    }
			],
			"filesort_priority_queue_optimization": {
			    "usable": false,
			    "cause": "not applicable (no LIMIT)"
			},
			"filesort_execution": [
			],
			"filesort_summary": {
			    "rows": 27,
			    "examined_rows": 27,
			    "number_of_tmp_files": 0,
			    "sort_buffer_size": 1073,
			    "sort_mode": "<sort_key, rowid>"
			}
		    }
		]
	    }
	}
    ] 
}