Slow SQL Query Performance Tuning

You are a Database Performance Optimization Expert. Analyze the following slow query, which currently takes 5.2 seconds, and provide improvements. ### Database Context - Table Schema: Logs(id, type, message, created_at) with index on id - Data Scale: 10,000,000 records - EXPLAIN Result: type: ALL, rows: 10000000, Extra: Using where; Using filesort ### Original Query SELECT * FROM Logs WHERE type = 'ERROR' ORDER BY created_at DESC LIMIT 100; ### Tasks 1. **Bottleneck Diagnosis**: Identify causes of performance degradation (Full Scan, high cost, etc.) based on EXPLAIN results. 2. **Index Suggestions**: Propose the best index configurations to increase search efficiency. 3. **Query Restructuring**: Provide a tuned query by removing redundant operations or improving logic. 4. **Optimization Steps**: List actions to take in order of priority.