Explain是我们常用的查询分析工具,可以对查询语句的执行方式进行评估,给出很多有用的线索。 但他仅仅是评估,不是实际的执行情况,比如结果中的rows,可能和实际结果相差甚大。 Explain Analyze是MySQL8中提供的新工具,牛X之处在于可以给出实际执行情况。 Explain Analyze是一个查询性能分析工具,可以详细的显示出 查询语...
DFESerialize – Serializes a query’s final results into a JSON string serialization, mapping each input solution to the appropriate variable name. For node and edge results, these results are serialized into a map of entity properties and metadata. DFESort – Takes an input relation and produces...
使用EXPLAIN 查看执行计划, 5.6后可以加参数 EXPLAIN FORMAT=JSON xxx输出json格式的信息。 FORMAT=JSON格式的内容可参考8.8.2 EXPLAIN Output Format中的相关部分。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 +---+---+---+---+---+---+ ...
For more information about how to use this format, see SQL Plan Management. plan_cache The EXPLAIN statement outputs results in the row format, with the Plan Cache information as a warning. brief DotGraph JSON The following is an example when FORMAT is "brief" in EXPLAIN: EXPLAIN FORMAT =...
查询执行计划语法explain查询语句explainformat=json 以json格式,输出查询的详情,包括查询代价 show warnings 展示查询计划的扩展信息 查询计划输出内容 MySQLexplain使用简介 explain: 查看执行计划,使用explain关键字可以模拟优化器执行SQL查询语句,从而知道MYSQL是如何处理你的SQL语句的。分析你的查询语句或是表结构的性能瓶...
JSON: Renders the query plan in JSON format. This option is compatible only with VERBOSE. ANNOTATED: Embeds optimizer hints that encapsulate the query plan for this query. This option is compatible with LOCAL and VERBOSE. sql-statement A query or DML statement—for example, SELECT, INSERT, UPD...
explain输出的每一行表示一张表,输出行中的列值在表8.1中做了总结,并且做了更详细的说明。 列名 json名 意义说明id...、DELETE删除、INSERT插入和UPDATE更新语句,并且提供具体mysql执行信息。explain对于在查询中的每张表都返回一行信息。而表中展示的顺序就是mysql读取并执行他们的顺序...
id (JSON name: select_id) SQL查询中的序列号。 select_type (JSON name: none) 查询的类型,可以是下表的任何一种类型: 查询类型例子: 1、SIMPLE 简单查询(不适用union和子查询的) mysql> explain select * from staff; +---+---+---+---+---+---+---+---+---+---+| id |select_type...
How to use the new JSON format We cannot talk about a new feature without an example, so let's look at a simple SELECT query: mysql> EXPLAIN FORMAT=TREE SELECT name, quantity FROM orders JOIN items i ON item_id = i.id WHERE quantity > 1000; ...
Here is the same query, with JSON output formatting: EXPLAIN (FORMAT JSON) SELECT * FROM foo; QUERY PLAN --- [ + { + "Plan": { + "Node Type": "Seq Scan",+ "Relation Name": "foo", + "Alias": "foo", + "Startup Cost": 0.00, + "Total Cost": 155.00, + "Plan Rows": ...