Is it correct to attach an index to each column of a large table? What are the features?

Attaching an index to every column of a large table is not always correct and can lead to negative consequences:

• Resource consumption: Each index takes up additional space on disk and in memory.

• Slowing down write operations: When inserting, updating, or deleting data, indexes need to be updated, which reduces performance.

• Redundancy: If queries do not use certain columns in filtering or sorting conditions, indexes on them are useless.

• Choosing the right indexes: It is better to create composite indexes on columns that are often used together in queries.

• Query analysis: Use EXPLAIN and other tools to understand which indexes actually help.

In summary: indexes should be created thoughtfully, based on query analysis and load, rather than simply attaching an index to every column.