Query optimization

Optimizing queries in RayDB helps improve performance, reduce execution time, and minimize resource consumption. This guide outlines best practices for writing efficient PostgreSQL queries.

1. Use Indexing

Indexes significantly improve query performance by reducing the amount of scanned data.

• Create indexes on frequently queried columns:

  CREATE INDEX idx_customer_id ON orders (customer_id);

• Use EXPLAIN ANALYZE to check if indexes are being utilized:

  EXPLAIN ANALYZE SELECT * FROM orders WHERE customer_id = 123;

2. Avoid SELECT *

Fetching only required columns reduces memory usage and improves query speed.

• Instead of:

  SELECT * FROM users;

• Use:

  SELECT id, name, email FROM users;

3. Optimize Joins

Joining large tables can be costly. Use the appropriate JOIN type and indexing.

• Ensure foreign keys are indexed for efficient joins:

  CREATE INDEX idx_order_user ON orders (user_id);

• Use EXPLAIN ANALYZE to detect slow joins and optimize accordingly.

4. Use Proper Data Types

Selecting the right data type ensures better performance and lower storage usage.

• Use INTEGER instead of TEXT for IDs.
• Use TIMESTAMPTZ instead of TEXT for date values.

5. Limit Result Sets

Fetching large datasets can slow down performance. Use LIMIT and OFFSET where necessary:

SELECT * FROM logs ORDER BY created_at DESC LIMIT 100;

6. Optimize Write Queries

• Use batch inserts instead of single-row inserts for bulk data:

  INSERT INTO orders (customer_id, total) VALUES (1, 100), (2, 200), (3, 300);

• Avoid frequent UPDATE operations on indexed columns, as they can cause bloat.

7. Use Connection Pooling

Efficiently manage database connections using a connection pooler like PgBouncer to reduce latency and resource consumption.

8. Monitor Query Performance

• Use pg_stat_statements to track slow queries:

  SELECT query, calls, total_time FROM pg_stat_statements ORDER BY total_time DESC LIMIT 10;

• Regularly VACUUM ANALYZE tables to update statistics and improve planner performance:

  VACUUM ANALYZE;

Best Practices

• Analyze execution plans with EXPLAIN ANALYZE.
• Cache frequent queries where applicable.
• Partition large tables for better query performance.

For more insights, refer to Performance Tuning.