PostgreSQL 链接池

• 每个链接一个进程
• 最大链接数 max_connections
• 进程内存分为 - 默认每个链接 10M 左右
  • 本地内存
    • work_mem - 默认 4M
      • ORDER BY, DISTINCT, JOIN
    • maintenance_work_mem
      • autovacuum_work_mem
      • VACUUM
    • temp_buffers - 默认 8M
      • 临时表
  • 共享内存
    • shared_buffers
    • wal_buffers
    • Commit Log
• 参考
  • What to Check if PostgreSQL Memory Utilization is High
  • Scaling Connections in Postgres
  • https://pgtune.leopard.in.ua/
  • https://gist.github.com/rgreenjr/3637525

select * from pg_stat_activity;
select * FROM pg_stat_activity where state <> 'idle';

show max_connections;

show work_mem;
show autovacuum_work_mem;
show maintenance_work_mem;
show temp_buffers;
show shared_buffers;
show wal_buffers;