{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "0.60"
},
"table": {
"table_name": "cscart_product_reviews",
"access_type": "index_merge",
"possible_keys": [
"idx_product_id",
"idx_user_id"
],
"key": "intersect(idx_product_id,idx_user_id)",
"key_length": "3,3",
"rows_examined_per_scan": 1,
"rows_produced_per_join": 1,
"filtered": "100.00",
"using_index": true,
"cost_info": {
"read_cost": "0.50",
"eval_cost": "0.10",
"prefix_cost": "0.60",
"data_read_per_join": "1K"
},
"used_columns": [
"product_review_id",
"product_id",
"user_id"
],
"attached_condition": "((`dev2`.`cscart_product_reviews`.`user_id` = 0) and (`dev2`.`cscart_product_reviews`.`product_id` = 28917))"
}
}
}