{"description":"MySQL (8.0.22)https://sikushima.hatenablog.com/entry/2019/04/10/181921 \u30ad\u30e3\u30c3\u30b7\u30e5\u3055\u308c\u306a\u3044\u6a21\u69d8\u3002 SET optimizer_trace=\"enabled=on\";SET optimizer_trace_max_mem_size = 1048576;select count(*) from tab1 a,tab1 b,tab1 c;select * from information_schema.optimizer_trace\\G SET optimizer_trace=\"enabled=off\"; select @@pro\u2026","provider_url":"https://hatena.blog","blog_title":"HTN20190109\u306e\u65e5\u8a18","title":"\u5b9f\u884c\u8a08\u753b\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u6709\u7121","height":"190","url":"https://htn20190109.hatenablog.com/entry/2021/06/20/163438","author_name":"HTN20190109","image_url":null,"version":"1.0","blog_url":"https://htn20190109.hatenablog.com/","provider_name":"Hatena Blog","type":"rich","published":"2021-06-20 16:34:38","author_url":"https://blog.hatena.ne.jp/HTN20190109/","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fhtn20190109.hatenablog.com%2Fentry%2F2021%2F06%2F20%2F163438\" title=\"\u5b9f\u884c\u8a08\u753b\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u6709\u7121 - HTN20190109\u306e\u65e5\u8a18\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","width":"100%","categories":["DB"]}