Re: Changing default value of wal_sync_method to open_datasync on Linux

2018-03-24 Thread MauMau
From: Robert Haas I also said it would be worse on spinning disks. Also, Yoshimi Ichiyanagi did not find it to be true even on NVRAM. Yes, let me withdraw this proposal. I couldn't see any performance difference even with ext4 volume on a PCIe flash memory. Regards MauMau

Re: Changing default value of wal_sync_method to open_datasync on Linux

2018-03-22 Thread Robert Haas
On Mon, Feb 19, 2018 at 7:27 PM, Tsunakawa, Takayuki wrote: > The reason for change is better performance. Robert Haas said open_datasync > was much faster than fdatasync with NVRAM in this thread: I also said it would be worse on spinning disks. Also, Yoshimi

Re: Changing default value of wal_sync_method to open_datasync on Linux

2018-02-19 Thread Andres Freund
On 2018-02-20 01:56:17 +, Tsunakawa, Takayuki wrote: > Disabling the filesystem barrier is a valid tuning method as the PG manual > says: I don't think it says that: > https://www.postgresql.org/docs/devel/static/wal-reliability.html > > [Excerpt] > Recent SATA drives (those following

RE: Changing default value of wal_sync_method to open_datasync on Linux

2018-02-19 Thread Tsunakawa, Takayuki
From: Andres Freund [mailto:and...@anarazel.de] > Indeed. My past experience with open_datasync on linux shows it to be slower > by roughly an order of magnitude. Even if that would turn out not to be > the case anymore, I'm *extremely* hesitant to make such a change. Thanks for giving so quick

Re: Changing default value of wal_sync_method to open_datasync on Linux

2018-02-19 Thread Mark Kirkwood
On 20/02/18 13:27, Tsunakawa, Takayuki wrote: Hello, I propose changing the default value of wal_sync_method from fdatasync to open_datasync on Linux. The patch is attached. I'm feeling this may be controversial, so I'd like to hear your opinions. The reason for change is better

Re: Changing default value of wal_sync_method to open_datasync on Linux

2018-02-19 Thread Andres Freund
Hi, On 2018-02-20 00:27:47 +, Tsunakawa, Takayuki wrote: > I propose changing the default value of wal_sync_method from fdatasync > to open_datasync on Linux. The patch is attached. I'm feeling this > may be controversial, so I'd like to hear your opinions. Indeed. My past experience with