Re: MultiXact\SLRU buffers configuration

I'm benchmarked v17 patches.

Testing was done on a 96-core machine, with PGDATA completely placed in tmpfs.

PostgreSQL was built with CFLAGS -O2.

for-update PgBench script:

\set aid random_zipfian(1, 100, 2)
begin;
select :aid from pgbench_accounts where aid = :aid for update;
update pgbench_accounts set abalance = abalance + 1 where aid = :aid;
update pgbench_accounts set abalance = abalance * 2 where aid = :aid;
update pgbench_accounts set abalance = abalance - 2 where aid = :aid;
end;

Before each test sample data was filled with "pgbench -i -s 100", testing was performed 3 times for 1 hour each test.

The benchmark results are presented with changing multi_xact_members_buffers and multicast_offsets_buffers (1:2 respectively):

settings                          tps
multixact_members_buffers_64Kb   693.2
multixact_members_buffers_128Kb  691.4
multixact_members_buffers_192Kb  696.3
multixact_members_buffers_256Kb  694.4
multixact_members_buffers_320Kb  692.3
multixact_members_buffers_448Kb  693.7
multixact_members_buffers_512Kb  693.3
vanilla                          676.1

Best regards, Dmitry Vasiliev.