MySQL Simple optimization method

Optimization steps:
1. See if SQL can be optimized.
2. See if the index can be optimized.
3. See if the table structure can be optimized.

Show table status from databases like ' tablename% '; View the capacity, index, and size of a data file for a table

Show Processlist; View the current link situation.
Explain SQL \G//View SQL uses the index of the case.
You can view the current SQL CPU, IO, and so on when you are sure that the index is using no problems.
Set Profiling=on;
Run SQL;
Show profiles;//Get Query ID
Show profile CPU, block IO for query ID; View CPU, IO usage.

Common methods:
1. When you find that SQL uses an index, but the index is not used correctly, you can force the use of other indexes ... forces index (INDEX_NAME) from table_name;
2. For SQL that uses an index (single-table query) with or or in operations, the UNION all can be used to basically save about 1/2 to 2/3 of the time.
3. Select only the columns to use.

MySQL Simple optimization method