How to tune PostgreSQL configuration file for optimal usage of memory parameters? - shiviyer/Blogs GitHub Wiki

Tuning PostgreSQL's configuration file (postgresql.conf) for optimal memory usage involves adjusting several key parameters based on your system's resources and workload. Here's how to do it:

  1. shared_buffers:

    • Controls the amount of memory dedicated to caching data.
    • Recommended Setting: Typically set to 25-40% of the total system RAM.

  2. work_mem:

    • Specifies the amount of memory used for query operations like sorts and joins.
    • Recommended Setting: Depends on your workload and the number of connections. Be cautious, as each query operation can use up to this amount of memory.

  3. maintenance_work_mem:

    • Allocated for maintenance tasks like VACUUM and CREATE INDEX.
    • Recommended Setting: Higher than work_mem, especially for larger databases. A general recommendation is 5-10% of total system RAM but not more than 1GB is often suggested.

  4. effective_cache_size:

    • Helps the planner estimate the effective size of the disk cache.
    • Recommended Setting: 50-75% of the total RAM.

  5. wal_buffers:

    • Size of the buffers used for WAL (Write-Ahead Logging).
    • Recommended Setting: Set to 1-3% of shared_buffers, but the default setting is often adequate.

  6. temp_buffers:

    • Amount of RAM used for temporary buffers within each session.
    • Recommended Setting: Depends on the application's use of temporary tables.

  7. max_connections:

    • Impacts memory usage as some memory is allocated per connection.
    • Recommended Setting: Set based on your application needs and available resources.

Remember, these recommendations are starting points. The optimal settings depend on your specific use case, and it's important to monitor the system's performance and adjust these parameters as needed. Always test changes in a controlled environment before applying them in production. Additionally, consider using tools like pgtune which provide configuration suggestions based on your system's specifications.