Patch applied by Magnus.
---
ITAGAKI Takahiro wrote:
> The attached is a patch to define O_DIRECT by ourselves on Windows,
> and to map O_DIRECT to FILE_FLAG_NO_BUFFERING.
>
> There will be a consistency in our support betw
I've done some further looking aruond at this, and I've been unable to find
any references to disk systems with sector size > 8192 bytes (which is what
the alignment of the buffers per XLOG_BLCKSZ, at leastby default).
So I'll commit this fairly simple patch, and we'll revert it or add runtime
che
Your patch has been added to the PostgreSQL unapplied patches list at:
http://momjian.postgresql.org/cgi-bin/pgpatches
It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.
---
IT
IIRC, we're still waiting for performance numbers showing there exists a
win from this patch.
//Magnus
Bruce Momjian wrote:
> Magnus, where are on this?
>
> ---
>
> Magnus Hagander wrote:
>> We're ok with the alignment issu
Magnus, where are on this?
---
Magnus Hagander wrote:
> We're ok with the alignment issues provided the is code added to reject
> O_DIRECT if the sector size is too large.
>
> We also said we need to see some performance nu
Are there any performance numbers on this?
---
ITAGAKI Takahiro wrote:
> The attached is a patch to define O_DIRECT by ourselves on Windows,
> and to map O_DIRECT to FILE_FLAG_NO_BUFFERING.
>
> There will be a consistency i
We're ok with the alignment issues provided the is code added to reject
O_DIRECT if the sector size is too large.
We also said we need to see some performance numbers on the effect of
the patch before it goes in.
//Magnus
Bruce Momjian wrote:
> So, do we want this patch? Are we OK on WIN32 ali
So, do we want this patch? Are we OK on WIN32 alignment issues?
---
ITAGAKI Takahiro wrote:
> The attached is a patch to define O_DIRECT by ourselves on Windows,
> and to map O_DIRECT to FILE_FLAG_NO_BUFFERING.
>
> There w
D] On Behalf Of Chuck McDevitt
Sent: Tuesday, January 16, 2007 11:09 PM
To: Takayuki Tsunakawa; Magnus Hagander
Cc: ITAGAKI Takahiro; pgsql-patches@postgresql.org
Subject: Re: [pgsql-patches] O_DIRECT support for Windows
People seem to be confusing sector size and cluster size.
Microsoft Windows as
> >> I think many people can benefit from Itagaki-san's proposal, and
> >> NO_BUFFERING should be default. Isn't it very rare that disks with
> >> sector size larger than 8KB are used?
> >
> > Definitly very rare.
> >
> >
> >> Providing a way (such as
> >> wal_sync_method) to avoid NO_BUFFERING is
> People seem to be confusing sector size and cluster size.
>
> Microsoft Windows assumes sectors are 8k or less on hard drives (99% are
> 512 bytes).
Do you have any doc ref for this? I beleive you but I've been searching for
docs on that and found nothing.
>
> Cluster size is the allocation
Behalf Of Takayuki
Tsunakawa
Sent: Tuesday, January 16, 2007 4:53 PM
To: Magnus Hagander
Cc: ITAGAKI Takahiro; pgsql-patches@postgresql.org
Subject: Re: [pgsql-patches] O_DIRECT support for Windows
Hello, Magnus-san, Itagaki-san
From: "Magnus Hagander" <[EMAIL PROTECTED]>
>>
Hello, Magnus-san, Itagaki-san
From: "Magnus Hagander" <[EMAIL PROTECTED]>
>> I think many people can benefit from Itagaki-san's proposal, and
>> NO_BUFFERING should be default. Isn't it very rare that disks with
>> sector size larger than 8KB are used?
>
> Definitly very rare.
>
>
>> Providing a
On Tue, Jan 16, 2007 at 10:59:11AM +0900, Takayuki Tsunakawa wrote:
> From: "Magnus Hagander" <[EMAIL PROTECTED]>
> > ITAGAKI Takahiro wrote:
> >> Do you mean there are drives that have larger sector size than 8kB?
> >> We've already put the xlog buffer along the alignment of
> >> ALIGNOF_XLOG_BUFF
From: "Magnus Hagander" <[EMAIL PROTECTED]>
> ITAGAKI Takahiro wrote:
>> Do you mean there are drives that have larger sector size than 8kB?
>> We've already put the xlog buffer along the alignment of
>> ALIGNOF_XLOG_BUFFER (typically 8192 bytes).
>> But if there are such drives, using FILE_FLAG_NO
ITAGAKI Takahiro wrote:
> Magnus Hagander <[EMAIL PROTECTED]> wrote:
>
>> FILE_FLAG_NO_BUFFERING requires that *all* I/O follows:
>> * File access must begin at offsets that are integer multples of the
>> volume sector size.
>> * File access must be for number of bytes that are integer multiples
Magnus Hagander <[EMAIL PROTECTED]> wrote:
> FILE_FLAG_NO_BUFFERING requires that *all* I/O follows:
> * File access must begin at offsets that are integer multples of the
> volume sector size.
> * File access must be for number of bytes that are integer multiples of
> the volume sector size.
On Mon, Jan 15, 2007 at 05:36:09PM +0900, ITAGAKI Takahiro wrote:
> The attached is a patch to define O_DIRECT by ourselves on Windows,
> and to map O_DIRECT to FILE_FLAG_NO_BUFFERING.
>
> There will be a consistency in our support between Windows and other OSes
> that have O_DIRECT. Also, there i
The attached is a patch to define O_DIRECT by ourselves on Windows,
and to map O_DIRECT to FILE_FLAG_NO_BUFFERING.
There will be a consistency in our support between Windows and other OSes
that have O_DIRECT. Also, there is the following comment that says, I read,
we should do so.
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