1.查询语句

SELECT menu_id, item_id, SUM(status) >= 0 "status" FROM item_activation_in_menu activation WHERE menu_id IN ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d', 'f8042ee6-0de3-497c-8842-fc2699405fc5', 'fd436116-3b59-44aa-be74-115b4175b971', '7335cd44-c32a-40eb-88d3-e36e8efb24e2', '0d5fbd56-64a2-4d2b-b533-629f09afdd2b', '2ebf6f40-7e08-4888-93ce-499e241a9d85') GROUP BY menu_id, item_id;

现在的索引(menu_id, item_id,status).

表有765万行，count(distinct menu_id)的值是16，从trace中发现是走了全表扫描。使用hint skip_scan无效。下面是trace信息。

mysql> select trace from `information_schema`.`optimizer_trace`\G
*************************** 1. row ***************************
trace: {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"IN_uses_bisection": true
},
{
"expanded_query": "/* select#1 */ select `item_activation_in_menu`.`menu_id` AS `menu_id`,`item_activation_in_menu`.`item_id` AS `item_id`,(sum(`item_activation_in_menu`.`status`) >= 0) AS `status` from `item_activation_in_menu` where (`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85')) group by `item_activation_in_menu`.`menu_id`,`item_activation_in_menu`.`item_id`"
}
]
}
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))"
}
]
}
},
{
"substitute_generated_columns": {
}
},
{
"table_dependencies": [
{
"table": "`item_activation_in_menu`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
]
}
]
},
{
"ref_optimizer_key_uses": [
]
},
{
"rows_estimation": [
{
"table": "`item_activation_in_menu`",
"range_analysis": {
"table_scan": {
"rows": 7690706,
"cost": 830416
},
"potential_range_indexes": [
{
"index": "PRIMARY",
"usable": false,
"cause": "not_applicable"
},
{
"index": "item_act_item_id_fk",
"usable": false,
"cause": "not_applicable"
},
{
"index": "menu_id",
"usable": true,
"key_parts": [
"menu_id",
"id"
]
},
{
"index": "idx_mid_iid_st",
"usable": true,
"key_parts": [
"menu_id",
"item_id",
"status",
"id"
]
}
],
"best_covering_index_scan": {
"index": "idx_mid_iid_st",
"cost": 2.64865e+06,
"chosen": false,
"cause": "cost"
},
"setup_range_conditions": [
],
"group_index_range": {
"chosen": false,
"cause": "not_applicable_aggregate_function"
},
"skip_scan_range": {
"chosen": false,
"cause": "has_group_by"
},
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "menu_id",
"ranges": [
"0d5fbd56-64a2-4d2b-b533-629f09afdd2b <= menu_id <= 0d5fbd56-64a2-4d2b-b533-629f09afdd2b",
"2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d <= menu_id <= 2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d",
"2ebf6f40-7e08-4888-93ce-499e241a9d85 <= menu_id <= 2ebf6f40-7e08-4888-93ce-499e241a9d85",
"7335cd44-c32a-40eb-88d3-e36e8efb24e2 <= menu_id <= 7335cd44-c32a-40eb-88d3-e36e8efb24e2",
"f8042ee6-0de3-497c-8842-fc2699405fc5 <= menu_id <= f8042ee6-0de3-497c-8842-fc2699405fc5",
"fd436116-3b59-44aa-be74-115b4175b971 <= menu_id <= fd436116-3b59-44aa-be74-115b4175b971"
],
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": false,
"rows": 4467039,
"cost": 4.90682e+06,
"chosen": false,
"cause": "cost"
},
{
"index": "idx_mid_iid_st",
"ranges": [
"0d5fbd56-64a2-4d2b-b533-629f09afdd2b <= menu_id <= 0d5fbd56-64a2-4d2b-b533-629f09afdd2b",
"2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d <= menu_id <= 2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d",
"2ebf6f40-7e08-4888-93ce-499e241a9d85 <= menu_id <= 2ebf6f40-7e08-4888-93ce-499e241a9d85",
"7335cd44-c32a-40eb-88d3-e36e8efb24e2 <= menu_id <= 7335cd44-c32a-40eb-88d3-e36e8efb24e2",
"f8042ee6-0de3-497c-8842-fc2699405fc5 <= menu_id <= f8042ee6-0de3-497c-8842-fc2699405fc5",
"fd436116-3b59-44aa-be74-115b4175b971 <= menu_id <= fd436116-3b59-44aa-be74-115b4175b971"
],
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": true,
"rows": 4488053,
"cost": 1.54567e+06,
"chosen": false,
"cause": "cost"
}
],
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
}
}
}
}
]
},
{
"considered_execution_plans": [
{
"plan_prefix": [
],
"table": "`item_activation_in_menu`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 7690706,
"access_type": "scan",
"resulting_rows": 7.69071e+06,
"cost": 830414,
"chosen": true,
"use_tmp_table": true
}
]
},
"condition_filtering_pct": 100,
"rows_for_plan": 7.69071e+06,
"cost_for_plan": 830414,
"sort_cost": 7.69071e+06,
"new_cost_for_plan": 8.52112e+06,
"chosen": true
}
]
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))",
"attached_conditions_computation": [
],
"attached_conditions_summary": [
{
"table": "`item_activation_in_menu`",
"attached": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))"
}
]
}
},
{
"optimizing_distinct_group_by_order_by": {
"simplifying_group_by": {
"original_clause": "`item_activation_in_menu`.`menu_id`,`item_activation_in_menu`.`item_id`",
"items": [
{
"item": "`item_activation_in_menu`.`menu_id`"
},
{
"item": "`item_activation_in_menu`.`item_id`"
}
],
"resulting_clause_is_simple": true,
"resulting_clause": "`item_activation_in_menu`.`menu_id`,`item_activation_in_menu`.`item_id`"
}
}
},
{
"reconsidering_access_paths_for_index_ordering": {
"clause": "GROUP BY",
"steps": [
],
"index_order_summary": {
"table": "`item_activation_in_menu`",
"index_provides_order": true,
"order_direction": "asc",
"index": "idx_mid_iid_st",
"plan_changed": false
}
}
},
{
"finalizing_table_conditions": [
{
"table": "`item_activation_in_menu`",
"original_table_condition": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))",
"final_table_condition ": "(`item_activation_in_menu`.`menu_id` in ('2d6e4dbc-9ccf-49cd-a924-ba5b646fc07d','f8042ee6-0de3-497c-8842-fc2699405fc5','fd436116-3b59-44aa-be74-115b4175b971','7335cd44-c32a-40eb-88d3-e36e8efb24e2','0d5fbd56-64a2-4d2b-b533-629f09afdd2b','2ebf6f40-7e08-4888-93ce-499e241a9d85'))"
}
]
},
{
"refine_plan": [
{
"table": "`item_activation_in_menu`"
}
]
},
{
"considering_tmp_tables": [
]
}
]
}
},
{
"join_execution": {
"select#": 1,
"steps": [
]
}
}
]
}
1 row in set (0.01 sec)