Re: huge SubtransSLRU and SubtransBuffer wait_event

2024-02-02 Thread Alvaro Herrera
On 2024-Feb-02, James Pang (chaolpan) wrote: > Possible to increase Subtrans SLRU buffer size ? Not at present -- you need to recompile after changing NUM_SUBTRANS_BUFFERS in src/include/access/subtrans.h, NUM_MULTIXACTOFFSET_BUFFERS and NUM_MULTIXACTMEMBER_BUFFERS in src/include/access/multix

Re: huge SubtransSLRU and SubtransBuffer wait_event

2024-02-02 Thread Lars Aksel Opsahl
>From: James Pang (chaolpan) Sent: Friday, February 2, 2024 >7:47 AMTo: Laurenz Albe ; >pgsql-performance@lists.postgresql.org >Subject: RE: huge SubtransSLRU and >SubtransBuffer wait_event > > Our case is 1) we use PL/PGSQL procedure1-->procedure2 (update table > ;commit); 2) appli

Re: huge SubtransSLRU and SubtransBuffer wait_event

2024-02-02 Thread Nikolay Samokhvalov
On Thu, Feb 1, 2024 at 04:42 Laurenz Albe wrote: > Today, the only feasible solution is not to create more than 64 > subtransactions > (savepoints or PL/pgSQL EXCEPTION clauses) per transaction. Sometimes, a single subtransaction is enough to experience a bad SubtransSLRU spike: https://postgre

Re: huge SubtransSLRU and SubtransBuffer wait_event

2024-02-02 Thread Laurenz Albe
On Fri, 2024-02-02 at 02:04 -0800, Nikolay Samokhvalov wrote: > On Thu, Feb 1, 2024 at 04:42 Laurenz Albe wrote: > > Today, the only feasible solution is not to create more than 64 > > subtransactions > > (savepoints or PL/pgSQL EXCEPTION clauses) per transaction. > > I think 64+ nesting level i