PgSQL 12 on WinSrv ~3x faster than on Linux

Dear All,

I have demo stand on Hyper-V (2xIntel E5-2650v2, 256GB RAM, Intel SSDs in RAID):

* One VM with 1C application Server

* 2 database VMs with same database imported into each PostgreSQL (~56Gb, "1C accounting 3.0" config):

1. CentOS 7 with postgresql_12.6_6.1C_x86_64 (distribution with special patches for running 1C), VM is updated with LIS for Hyper-V

2. Windows Server 2019 with same postgresql_12.6_6.1C_x86_64

My real life test is to "register" 10 _same_ documents (провести документы) in each of 1C/PostgreSQL DBs. Both PostgreSQL DBs are identical and just before test imported to PostgreSQL via application server (DT import).

On Windows Server test procedure takes 20-30 seconds, on Linux it takes 1m-1m10seconds. PostgreSQL VMs are running on same Hypervisor with same resources assigned to each of them.

Tuning PostgreSQL config and/or CentOS don't make any difference. Contrary on Windows VM we have almost 3x better performance with stock PostgreSQL config.

Any ideas what's wrong? For me such a big difference on identical databases/queries looks strange.

--
Taras Savchuk