{ pkgs, config, ... }:
let
  cfg = config.services.postgresql;
in
{
  services.postgresql = {
    enable = true;
    package = pkgs.postgresql_16;
    enableJIT = true;
    # Settings taken from [PGTune](https://pgtune.leopard.in.ua/)
    settings = {
      max_connections = "300";
      shared_buffers = "2GB";
      effective_cache_size = "6GB";
      maintenance_work_mem = "512MB";
      checkpoint_completion_target = 0.9;
      wal_buffers = "16MB";
      default_statistics_target = 100;
      random_page_cost = 4;
      effective_io_concurrency = 2;
      work_mem = "2621kB";
      huge_pages = "off";
      min_wal_size = "1GB";
      max_wal_size = "4GB";
      max_worker_processes = 8;
      max_parallel_workers_per_gather = 4;
      max_parallel_workers = 8;
      max_parallel_maintenance_workers = 4;
    };
  };
  systemd.timers.pg-autovacuum = {
    description = "Timer for Postgres Autovacuum";
    timerConfig = {
      OnCalendar = "*-*-* 01:00:00";
      Unit = "pg-autovacuum.service";
    };
  };
  systemd.services.pg-autovacuum = {
    description = "Vacuum all Postgres databases.";
    requisite = [ "postgresql.service" ];
    wantedBy = [ "multi-user.target" ];
    serviceConfig = {
      Type = "oneshot";
      User = "postgres";
      Group = "postgres";
      SyslogIdentifier = "pg-autovacuum";
      ExecStart = "${cfg.package}/bin/vacuumdb --all --echo --jobs=6 --parallel=5 --analyze --verbose";
    };
  };
}