CodeIgniter Speed Optimization

I need an experienced developer to increase the speed of my CodeIgniter website. The large database size is currently slowing it down.

Key requirements:
- Optimize the website's performance, focusing on database-related issues.
- Address large database size.

Ideal Skills & Experience:
- Strong expertise in CodeIgniter.
- Proficient in database optimization.
- Experience in performance tuning and speeding up websites.
- Familiar with best practices for managing large databases.

Please provide examples of similar work done.