MySQL Execution Plan analysis tool explain usage _php tutorial

MySQL Execution Plan analysis tool explain usage

For DBAs who are familiar with SQL's execution plan analysis techniques are critical to quickly locating database performance issues, here's a brief look at how to analyze MySQL's execution plan.
One, EXPLAIN usage explanation: EXPLAIN SELECT ...

Variant: 1. EXPLAIN EXTENDED SELECT ... "Decompile" The execution plan into a SELECT statement and run show WARNINGS to get the query statement optimized by the MySQL optimizer

2. EXPLAIN Partitions SELECT ... Explain for partitioned tables

Examples are shown below:

The specific explanations are as follows 1. Execution ID

Contains a set of numbers that, if they are the same, can be considered a group, executed from the top down; in all groups, the higher the ID value, the higher the priority, the first 2. Query type Select_type

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