What scenarios or situations can lead to decreased performance when working with Django ORM?

Performance degradation when working with Django ORM can occur in the following scenarios:

• N+1 queries: when a separate query is executed for each related object instead of using select_related or prefetch_related.
• Lack of indexes in the database: slow queries due to missing necessary indexes.
• Redundant queries: executing the same queries multiple times without caching.
• Large volumes of data: loading and processing too many records in a single query.
• Using .all() and subsequent filtering in Python instead of filtering at the database level.
• Complex annotations and aggregations without optimization.

Example of optimizing the N+1 problem:

# Poor:
books = Book.objects.all()
for book in books:
    print(book.author.name)  # Each book will trigger a separate query to author

# Good:
books = Book.objects.select_related('author').all()
for book in books:
    print(book.author.name)  # Single query with JOIN