Database Optimization: Effective Techniques

1. Database Design

Normalization: Suppose you have an Orders table storing information about orders:

CREATE TABLE Orders ( OrderID INT, CustomerName VARCHAR(100), ProductName VARCHAR(100), Quantity INT, Price DECIMAL(10, 2) );

If a customer has multiple orders, customer information will be duplicated. Normalization can split it into two tables

CREATE TABLE Customers ( CustomerID INT PRIMARY KEY, CustomerName VARCHAR(100) );

CREATE TABLE Orders ( OrderID INT PRIMARY KEY, CustomerID INT, ProductName VARCHAR(100), Quantity INT, Price DECIMAL(10, 2), FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID) );

2. Query Optimization

Using EXPLAIN:

EXPLAIN SELECT * FROM Orders WHERE Quantity > 10;

The EXPLAIN result shows how the database plans to execute the query, helping you optimize by creating indexes.

Optimizing JOIN:

If you have queries using JOINS that are not optimized, you can improve performance by creating indexes.

CREATE INDEX idx_customer_id ON Orders(CustomerID);

3. Index Management

Appropriate Indexing: Suppose you have frequent queries searching by CustomerID:

SELECT * FROM Orders WHERE CustomerID = 123;

Creating a index on CustomerID will help speed up the query

Index Maintenance: Perfomr REINDEX to refresh the indexes REINDEX TABLE Orders;

4. Caching

Using Redis: When there are frequest queries, you can store results in redis

import redis r = redis.Redis()

Store query result r.set('orders:customer:123', result)

Retrieve data from cache cached_result = r.get('orders:customer:123')

5. Transaction Optimization

Isolation Levels: Use appropriate isolation levels to avoid deadlocks

SET TRANSACTION ISOLATION LEVEL READ COMMITTED; BEGIN TRANSACTION; -- Perform actions COMMIT;:

Batch Processing: Insert data in bulk

INSERT INTO Orders (CustomerID, ProductName, Quantity, Price) VALUES (1, 'Product A', 10, 100.00), (2, 'Product B', 5, 50.00), (3, 'Product C', 20, 200.00);

6. Backup and Recovery

Backup Strategy: Implement full Backups and incremental backups:

Full backup pg_dump mydatabase > backup.sql

Incremental backup pg_dump --data-only mydatabase > incremental_backup.sql

7. Monitoring và Performance Tuning

Perormance Monitoring: Use tools like pgAdmin or Sql Server management Studio to track database activity and receive alerts on parformance issues. Tuning Parameters: Adjust configuration parameters such as max_connections, shared_buffers and work_mem to fit the load