{ "steps": [ { "join_preparation": { "select#": 1, "steps": [ { "expanded_query": "/* select#1 */ select `job_instances`.`jobState` AS `jobState`,`job_instances`.`status` AS `status` from `job_instances` where (`job_instances`.`jobName` = 'Ship_Christmas_Presents') order by `job_instances`.`jobInstanceId` desc limit 1" } ] } }, { "join_optimization": { "select#": 1, "steps": [ { "condition_processing": { "condition": "WHERE", "original_condition": "(`job_instances`.`jobName` = 'Ship_Christmas_Presents')", "steps": [ { "transformation": "equality_propagation", "resulting_condition": "multiple equal('Ship_Christmas_Presents', `job_instances`.`jobName`)" }, { "transformation": "constant_propagation", "resulting_condition": "multiple equal('Ship_Christmas_Presents', `job_instances`.`jobName`)" }, { "transformation": "trivial_condition_removal", "resulting_condition": "multiple equal('Ship_Christmas_Presents', `job_instances`.`jobName`)" } ] } }, { "table_dependencies": [ { "table": "`job_instances`", "row_may_be_null": false, "map_bit": 0, "depends_on_map_bits": [ ] } ] }, { "ref_optimizer_key_uses": [ { "table": "`job_instances`", "field": "jobName", "equals": "'Ship_Christmas_Presents'", "null_rejecting": false } ] }, { "rows_estimation": [ { "table": "`job_instances`", "range_analysis": { "table_scan": { "rows": 3849342, "cost": 846030 }, "potential_range_indices": [ { "index": "PRIMARY", "usable": false, "cause": "not_applicable" }, { "index": "jobId", "usable": false, "cause": "not_applicable" }, { "index": "jobName_State", "usable": true, "key_parts": [ "jobName", "jobState", "jobInstanceId" ] }, { "index": "finishedRunningAt", "usable": false, "cause": "not_applicable" }, { "index": "taskId", "usable": false, "cause": "not_applicable" }, { "index": "jobStateUpdatedAt", "usable": false, "cause": "not_applicable" }, { "index": "parentJobInstanceId", "usable": false, "cause": "not_applicable" }, { "index": "jobState", "usable": false, "cause": "not_applicable" }, { "index": "hostname", "usable": false, "cause": "not_applicable" }, { "index": "jobState_2", "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": "jobName_State", "ranges": [ "Ship_Christmas_Presents <= jobName <= Ship_Christmas_Presents" ], "index_dives_for_eq_ranges": true, "rowid_ordered": false, "using_mrr": false, "index_only": false, "rows": 26936, "cost": 32324, "chosen": true } ], "analyzing_roworder_intersect": { "usable": false, "cause": "too_few_roworder_scans" } }, "chosen_range_access_summary": { "range_access_plan": { "type": "range_scan", "index": "jobName_State", "rows": 26936, "ranges": [ "Ship_Christmas_Presents <= jobName <= Ship_Christmas_Presents" ] }, "rows_for_plan": 26936, "cost_for_plan": 32324, "chosen": true } } } ] }, { "considered_execution_plans": [ { "plan_prefix": [ ], "table": "`job_instances`", "best_access_path": { "considered_access_paths": [ { "access_type": "ref", "index": "jobName_State", "rows": 26936, "cost": 32323, "chosen": true }, { "access_type": "range", "cause": "heuristic_index_cheaper", "chosen": false } ] }, "cost_for_plan": 32323, "rows_for_plan": 26936, "chosen": true } ] }, { "attaching_conditions_to_tables": { "original_condition": "(`job_instances`.`jobName` = 'Ship_Christmas_Presents')", "attached_conditions_computation": [ ], "attached_conditions_summary": [ { "table": "`job_instances`", "attached": "(`job_instances`.`jobName` = 'Ship_Christmas_Presents')" } ] } }, { "clause_processing": { "clause": "ORDER BY", "original_clause": "`job_instances`.`jobInstanceId` desc", "items": [ { "item": "`job_instances`.`jobInstanceId`" } ], "resulting_clause_is_simple": true, "resulting_clause": "`job_instances`.`jobInstanceId` desc" } }, { "refine_plan": [ { "table": "`job_instances`", "pushed_index_condition": "(`job_instances`.`jobName` = 'Ship_Christmas_Presents')", "table_condition_attached": null } ] }, { "added_back_ref_condition": "((`job_instances`.`jobName` <=> 'Ship_Christmas_Presents'))" }, { "reconsidering_access_paths_for_index_ordering": { "clause": "ORDER BY", "index_order_summary": { "table": "`job_instances`", "index_provides_order": true, "order_direction": "desc", "disabled_pushed_condition_on_old_index": true, "index": "PRIMARY", "plan_changed": true, "access_type": "index_scan" } } } ] } }, { "join_execution": { "select#": 1, "steps": [ ] } } ] }