From 8afd86502ac68349cc4f00d480ca3d2d07f982e6 Mon Sep 17 00:00:00 2001 From: zhangyijun402 <2634360052@qq.com> Date: Fri, 29 Nov 2024 14:29:49 +0800 Subject: [PATCH] 10.8 Understanding the Query Execution Plan.md --- 10.8 Understanding the Query Execution Plan.md | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 10.8 Understanding the Query Execution Plan.md diff --git a/10.8 Understanding the Query Execution Plan.md b/10.8 Understanding the Query Execution Plan.md new file mode 100644 index 0000000..5c58e71 --- /dev/null +++ b/10.8 Understanding the Query Execution Plan.md @@ -0,0 +1,13 @@ +原文地址:https://dev.mysql.com/doc/refman/8.0/en/execution-plan-information.html + + + +## 10.8 Understanding the Query Execution Plan + +- [10.8.1 Optimizing Queries with EXPLAIN](https://dev.mysql.com/doc/refman/8.0/en/using-explain.html) +- [10.8.2 EXPLAIN Output Format](https://dev.mysql.com/doc/refman/8.0/en/explain-output.html) +- [10.8.3 Extended EXPLAIN Output Format](https://dev.mysql.com/doc/refman/8.0/en/explain-extended.html) +- [10.8.4 Obtaining Execution Plan Information for a Named Connection](https://dev.mysql.com/doc/refman/8.0/en/explain-for-connection.html) +- [10.8.5 Estimating Query Performance](https://dev.mysql.com/doc/refman/8.0/en/estimating-performance.html) + +Depending on the details of your tables, columns, indexes, and the conditions in your `WHERE` clause, the MySQL optimizer considers many techniques to efficiently perform the lookups involved in an SQL query. A query on a huge table can be performed without reading all the rows; a join involving several tables can be performed without comparing every combination of rows. The set of operations that the optimizer chooses to perform the most efficient query is called the “query execution plan”, also known as the [`EXPLAIN`](https://dev.mysql.com/doc/refman/8.0/en/explain.html) plan. Your goals are to recognize the aspects of the [`EXPLAIN`](https://dev.mysql.com/doc/refman/8.0/en/explain.html) plan that indicate a query is optimized well, and to learn the SQL syntax and indexing techniques to improve the plan if you see some inefficient operations.