Postgres Query Optimization Expert Needed

I'm in need of a seasoned Postgres specialist who can help me speed up my data retrieval queries.

We have a complex database design that supports an audited versioned file system, which may contain over 100 million items, so we need to optimise the queries and potentially the database structure

Main Issues:

- Long Execution Time: My current Postgres queries are taking too long to execute, which is hampering performance of my core functionality

Data Operations:

- Data Retrieval: The slow queries primarily involve data retrieval from large tables with millions of rows.

- Data Retrieval: complex joins required, sometimes with many database queries per user request

Ideal Skills:

- Extensive experience with Postgres

- Proficient in query optimization

- Skilled in handling large data sets

- Familiar with data retrieval operations

The freelancer should be able to identify the bottlenecks in my current setup and propose effective solutions to minimize execution time. Please provide examples of similar projects you've worked on in your proposal.

We are currently using some indexes on our tables but they seem insufficient for our needs.