| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> |
| Cc: | Yoshimi Ichiyanagi <ichiyanagi(dot)yoshimi(at)lab(dot)ntt(dot)co(dot)jp>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, "menjo(dot)takashi(at)lab(dot)ntt(dot)co(dot)jp" <menjo(dot)takashi(at)lab(dot)ntt(dot)co(dot)jp>, "ishizaki(dot)teruaki(at)lab(dot)ntt(dot)co(dot)jp" <ishizaki(dot)teruaki(at)lab(dot)ntt(dot)co(dot)jp> |
| Subject: | Re: [HACKERS][PATCH] Applying PMDK to WAL operations for persistent memory |
| Date: | 2018-01-26 01:37:08 |
| Message-ID: | CA+TgmoYaRx6c4k2eiRCjBkHLRwvi+5fYjsBJO86L2taU2yxdGw@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thu, Jan 25, 2018 at 8:32 PM, Tsunakawa, Takayuki
<tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> wrote:
> As I showed previously, regular file writes on PCIe flash, *not writes using PMDK on persistent memory*, was 20% faster with open_datasync than with fdatasync.
If I understand correctly, those results are all just pg_test_fsync
results. That's not reflective of what will happen when the database
is actually running. When you use open_sync or open_datasync, you
force WAL write and WAL flush to happen simultaneously, instead of
letting the WAL flush be delayed.
> And you said open_datasync was significantly faster than fdatasync. Could you show your results? What device and filesystem did you use?
I don't have the results handy at the moment. We found it to be
faster on a database benchmark where the WAL was stored on an NVRAM
device.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Masahiko Sawada | 2018-01-26 01:38:27 | Re: Fix a typo in autoprewarm.c |
| Previous Message | Petr Jelinek | 2018-01-26 01:36:42 | Re: [PATCH] Logical decoding of TRUNCATE |