thanks for you clarification about additional memory calculations: for 10k connections , 5625kB maybe fine. I justed looked through the discussions about memory allocation " https://www.postgresql.org/message-id/cba2406a-66bb-41ac-b1cf-bb898596e0e1%40vondra.me";, I feel confused about the statement "the memory 1000 connections 80MB there"
Thanks, James David Rowley <dgrowle...@gmail.com> 於 2025年8月18日週一 下午2:58寫道： > On Mon, 18 Aug 2025 at 18:23, James Pang <jamespang...@gmail.com> wrote: > > not tested and any regression found either, with 10k connections, > and "max_locks_per_transaction=128", it need about more than 1GB extra > memory,right? per my understanding, max_locks_per_transaction is the max > locked objects in a transaction (that's not an average locked objects at > the same time among all connections), but for past-path-lock slots, the > memory will be allocated based on this parameter after client connection > established, right? so, even no so many fast lock slots needed, for 10k > connections, extra memory got allocated there. We may test that in our > environment, and update then if anything found. > > Can you share how you came to 1GB extra? > > By my calculations, I believe it's an extra 5625 kB total for the > entire instance. > > select pg_size_pretty((max_locks_per_xact / 16 * 8 + > max_locks_per_xact / 16 * 4 * 16) * connections::numeric) from > (values(128,10000)) v(max_locks_per_xact, connections); > > David >
