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Re: Changing the default wal_sync_method to open_sync for

From: "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>
To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: Magnus Hagander <mha(at)sollentuna(dot)net>,Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org,pgsql-hackers-win32(at)postgresql(dot)org,Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>
Subject: Re: Changing the default wal_sync_method to open_sync for
Date: 2005-03-17 05:32:20
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackerspgsql-hackers-win32
On Wed, 16 Mar 2005, Bruce Momjian wrote:

> Magnus Hagander wrote:
>> I'd like to see this one also considered for 8.0.x, though I'd certainly
>> like to see some more testing as well. Perhaps it's suitable for the
>> "8.0.x with extended testing" that is planned for the ARC replacement
>> code?
>> It does make a huge difference on win32. While we definitly don't want
>> to risk data, a 60% speedup in write intensive apps is a *lot*.
> Notice we never default to open_sync.  However, on Win32, Magnus got a
> 60% speedup by using open_sync, implemented using
> FILE_FLAG_WRITE_THROUGH.  Now, because this the fastest on Win32, I
> think we should default to open_sync on Win32.  The attached patch
> implements this.

Considering how stable an Operating System Windows *isn't*, I think the 
first thing Magnus states very much goes against making this the default: 
"While we definitely don't want to risk data..." ...

Setting something like this that increases the risk to data should never 
be 'the default behaviour', but a conscious decision on the part of the 
administrator of the individual system ... and even then, with a good 
skull-n-cross bones warning around it so that they  understand the risks 

Marc G. Fournier           Hub.Org Networking Services (
Email: scrappy(at)hub(dot)org           Yahoo!: yscrappy              ICQ: 7615664

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