Returning unfiltered database tables from REST endpoints causes memory spikes and slow API response times. Implementing server-side filtering in Django REST Framework ensures databases return only relevant records.

1. Preventing Database Memory Overload

Fetching millions of database rows into Python memory crashes app servers. Filtering pushes SQL WHERE conditions to PostgreSQL directly.

2. Multi-Tenant Data Isolation & Security

Filtering queryset.filter(owner=request.user) ensures users only view their own private data records.