How did you configure PostgreSQL for optimal performance?

For optimal PostgreSQL performance, several key parameters are usually configured in the postgresql.conf file:

• shared_buffers — the amount of memory allocated for data caching. It is generally recommended to set this to about 25-40% of the system's RAM.
• work_mem — memory allocated for sorting and hashing operations for each query. Increasing this can speed up complex queries but requires caution to avoid exhausting memory.
• maintenance_work_mem — memory for maintenance operations such as VACUUM or CREATE INDEX.
• effective_cache_size — an estimate of the memory available for OS caching, which influences the query planner.
• max_connections — the maximum number of concurrent connections; should be set based on the expected load.
• checkpoint_segments (replaced by max_wal_size in newer versions) — affects the frequency of checkpoints, which is important for write performance.

Regular VACUUM and ANALYZE operations are also important for maintaining statistics and cleaning up.

Example configuration in postgresql.conf:

shared_buffers = 4GB
work_mem = 64MB
effective_cache_size = 12GB
max_connections = 100