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索引列的病情,我有一个非常简单的SQL where语句不良的SQL性能,其中对在MySQL
SELECT `genre_application`.`genre_id`
FROM `genre_application`
WHERE `genre_application`.`application_id` = 310633997
这需要2秒左右,即使在列索引。
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "2098202.80"
},
"table": {
"table_name": "genre_application",
"access_type": "index",
"key": "PRIMARY",
"used_key_parts": [
"genre_id",
"application_id"
],
"key_length": "8",
"rows_examined_per_scan": 10363019,
"rows_produced_per_join": 1036301,
"filtered": "10.00",
"using_index": true,
"cost_info": {
"read_cost": "1890942.42",
"eval_cost": "207260.38",
"prefix_cost": "2098202.80",
"data_read_per_join": "23M"
},
"used_columns": [
"genre_id",
"application_id"
],
"attached_condition": "(`genre_application`.`application_id` = 310633997)"
}
}
我该如何提高执行时间?
哇,这是一个快速回复。 Works perfect 00:20:00 \t SELECT'genre_application'.'genre_id' FROM'genre_application' WHERE'genre_application'.'application_id' = 310633997 LIMIT 0,300 \t 2行返回\t 0.00036秒/ 0.0000079秒 – dc10
@ dc10。 。 。非常好。加快99.982%! –
闻起来像查询缓存踢了。但我同意这是最佳索引。 –