Why are indexes not created for every field in PostgreSQL?

Indexes in PostgreSQL are not created for every field because:

• Indexes occupy additional space on disk.
• When inserting, updating, and deleting data, indexes need to be updated, which reduces write operation performance.
• Not all fields are used in search or sorting conditions, so an index for them is inefficient.

Therefore, indexes are only created for fields that are frequently involved in filtering, sorting, or joins to optimize queries without unnecessary index maintenance costs.