What do you look at first when it comes to query planning? What bottlenecks can you see?

When analyzing a query, I primarily look at:

• Execution plan (EXPLAIN) — to understand how the DBMS plans to execute the query.
• Index usage — checking whether indexes are used or if a full table scan occurs.
• Number of rows returned — a large volume can slow down execution.
• Join types — especially if there are nested loops or inefficient joins.
• Filters and WHERE conditions — how selective and optimal they are.

Potential bottlenecks include:

• Absence or improper use of indexes.
• Full scans of large tables (Full Table Scan).
• Incorrect join order or use of slow JOIN types.
• Redundant or inefficient subqueries.
• Large sorting or aggregation operations without optimization.

Based on this data, you can optimize the query by adding indexes, rewriting logic, or changing the data structure.